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Richacl #109

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Richacl #109

wants to merge 27 commits into from

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Andreas Gruenbacher and others added 27 commits October 23, 2011 19:15
@kvaneesh
vfs: Indicate that the permission functions take all the MAY_* flags
d5d1fb4 
Acked-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
@kvaneesh
vfs: Add hex format for MAY_* flag values
0f69c40 
We are going to add more flags and having them in hex format
make it simpler

Acked-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
@kvaneesh
vfs: Pass all mask flags down to iop->check_acl
bf56180 
Some file permission models differentiate between writing to a file
(MAY_WRITE) and appending to it (MAY_WRITE | MAY_APPEND).  Pass all the
mask flags down to iop->check_acl so that filesystems can distinguish
between writing and appending.

All users of iop->check_acl pass the mask value back into
posix_acl_permission(); strip off the additional mask flags there.

Acked-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
@kvaneesh
vfs: Add a comment to inode_permission()
518cbba 
Acked-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
@kvaneesh
vfs: Add generic IS_ACL() test for acl support
89e1033 
When IS_POSIXACL() is true, the vfs does not apply the umask.  Other acl
models will need the same exception, so introduce a separate IS_ACL()
test.

The IS_POSIX_ACL() test is still needed so that nfsd can determine when
the underlying file system supports POSIX ACLs (as opposed to some other
kind).

Acked-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
@kvaneesh
vfs: Add IS_RICHACL() test for richacl support
45481f1 
Introduce a new MS_RICHACL super-block flag and a new IS_RICHACL() test
which file systems like nfs can use.  IS_ACL() is true if IS_POSIXACL()
or IS_RICHACL() is true.

Acked-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
@kvaneesh
vfs: Optimize out IS_RICHACL() if CONFIG_FS_RICHACL is not defined
c684918 
if CONFIG_FS_RICHACL is not defined optimize out
the ACL check function.

Acked-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
@kvaneesh
vfs: Add new file and directory create permission flags
004723e 
Some permission models distinguish between the permission to create a
non-directory and a directory.  Pass this information down to
inode_permission() as mask flags

Acked-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
@kvaneesh
vfs: Add delete child and delete self permission flags
1654a09 
Normally, deleting a file requires write access to the parent directory.
Some permission models use a different permission on the parent
directory to indicate delete access.  In addition, a process can have
per-file delete access even without delete access on the parent
directory.

Introduce two new inode_permission() mask flags and use them in
may_delete()

Acked-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
@kvaneesh
vfs: Make the inode passed to inode_change_ok non-const
3437a82 
We will need to call iop->permission and iop->get_acl from
inode_change_ok() for additional permission checks, and both take a
non-const inode.

Acked-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
@kvaneesh
vfs: Add permission flags for setting file attributes
e963a4c 
Some permission models can allow processes to take ownership of a file,
change the file permissions, and set the file timestamps.  Introduce new
permission mask flags and check for those permissions in
inode_change_ok().

Acked-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
@kvaneesh
vfs: Make acl_permission_check() work for richacls
26dc449 
Acked-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
@kvaneesh
richacl: In-memory representation and helper functions
e210ab8 
A richacl consists of an NFSv4 acl and an owner, group, and other mask.
These three masks correspond to the owner, group, and other file
permission bits, but they contain NFSv4 permissions instead of POSIX
permissions.

Each entry in the NFSv4 acl applies to the file owner (OWNER@), the
owning group (GROUP@), literally everyone (EVERYONE@), or to a specific
uid or gid.

As in the standard POSIX file permission model, each process is the
owner, group, or other file class.  A richacl grants a requested access
only if the NFSv4 acl in the richacl grants the access (according to the
NFSv4 permission check algorithm), and the file mask that applies to the
process includes the requested permissions.

Acked-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
@kvaneesh
richacl: Permission mapping functions
36ee026 
We need to map from POSIX permissions to NFSv4 permissions when a
chmod() is done, from NFSv4 permissions to POSIX permissions when an acl
is set (which implicitly sets the file permission bits), and from the
MAY_READ/MAY_WRITE/MAY_EXEC/MAY_APPEND flags to NFSv4 permissions when
doing an access check in a richacl.

Acked-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
@kvaneesh
richacl: Compute maximum file masks from an acl
dc240c0 
Compute upper bound owner, group, and other file masks with as few
permissions as possible without denying any permissions that the NFSv4
acl in a richacl grants.

This algorithm is used when a file inherits an acl at create time and
when an acl is set via a mechanism that does not specify file modes
(such as via nfsd).  When user-space sets an acl, the file masks are
passed in as part of the xattr.

When setting a richacl, the file masks determine what the file
permission bits will be set to; see richacl_masks_to_mode().

Acked-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
@kvaneesh
richacl: Update the file masks in chmod()
6be646b 
Doing a chmod() sets the file mode, which includes the file permission
bits.  When a file has a richacl, the permissions that the richacl
grants need to be limited to what the new file permission bits allow.

This is done by setting the file masks in the richacl to what the file
permission bits map to.  The richacl access check algorithm takes the
file masks into account, which ensures that the richacl cannot grant too
many permissions.

It is possible to explicitly add permissions to the file masks which go
beyond what the file permission bits can grant (like the ACE4_WRITE_ACL
permission).  The POSIX.1 standard calls this an alternate file access
control mechanism.  A subsequent chmod() would ensure that those
permissions are disabled again.

Acked-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
@kvaneesh
richacl: Permission check algorithm
61bf134 
As in the standard POSIX file permission model, each process is the
owner, group, or other file class.  A process is

  - in the owner file class if it owns the file,
  - in the group file class if it is in the file's owning group or it
    matches any of the user or group entries, and
  - in the other file class otherwise.

Each file class is associated with a file mask.

A richacl grants a requested access if the NFSv4 acl in the richacl
grants the requested permissions (according to the NFSv4 permission
check algorithm) and the file mask that applies to the process includes
the requested permissions.

Acked-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
@kvaneesh
richacl: Create-time inheritance
9d9bef3 
When a new file is created, it can inherit an acl from its parent
directory; this is similar to how default acls work in POSIX (draft)
ACLs.

As with POSIX ACLs, if a file inherits an acl from its parent directory,
the intersection between the create mode and the permissions granted by
the inherited acl determines the file masks and file permission bits,
and the umask is ignored.

Acked-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
@kvaneesh
richacl: Check if an acl is equivalent to a file mode
8013f16 
This function is used to avoid storing richacls on disk if the acl can
be computed from the file permission bits.

Acked-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
@kvaneesh
richacl: Automatic Inheritance
5882a81 
Automatic Inheritance (AI) allows changes to the acl of a directory to
recursively propagate down to files and directories in the directory.

To implement this, the kernel keeps track of which permissions have been
inherited, and makes sure that permission propagation is turned off when
the file permission bits of a file are changed (upon create or chmod).

The actual permission propagation is implemented in user space.

AI works as follows:

 - When the ACL4_AUTO_INHERIT flag in the acl of a file is cleared, the
   file is not affected by AI.

 - When the ACL4_AUTO_INHERIT flag in the acl of a directory is set and
   a file or subdirectory is created in that directory, files created in
   the directory will have the ACL4_AUTO_INHERIT flag set, and all
   inherited aces will have the ACE4_INHERITED_ACE flag set.  This
   allows user space to distinguish between aces which have been
   inherited, and aces which have been explicitly added.

 - When the ACL4_PROTECTED acl flag in the acl of a file is set, AI will
   not modify the acl of the file.  This does not affect propagation of
   permissions from the file to its children (if the file is a
   directory).

Linux does not have a way of creating files without setting the file
permission bits, so all files created inside a directory with
ACL4_AUTO_INHERIT set will also have the ACL4_PROTECTED flag set.  This
effectively disables AI.

Protocols which support creating files without specifying permissions
can explicitly clear the ACL4_PROTECTED flag after creating a file (and
reset the file masks to "undo" applying the create mode; see
richacl_compute_max_masks()).  This is a workaround; a per-create or
per-process flag indicating to ignore the create mode when AI is in
effect would fix this problem.

Acked-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
@kvaneesh
richacl: xattr mapping functions
862d861 
Map between "system.richacl" xattrs and the in-kernel representation.

Acked-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
@kvaneesh
vfs: Cache richacl in struct inode
69d9df5 
Cache richacls in struct inode so that this doesn't have to be done
individually in each filesystem.

Acked-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
@kvaneesh
vfs: Add richacl permission check
e86e410 
Acked-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
@kvaneesh
ext4: Use IS_POSIXACL() to check for POSIX ACL support
434e398 
Use IS_POSIXACL() instead of a file system specific mount flag since we
have IS_POSIXACL() in the vfs already, anyway.

Acked-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
@kvaneesh
ext4: Implement rich acl for ext4
69b47fd 
Support the richacl permission model in ext4.  The richacls are stored
in "system.richacl" xattrs.This need to be enabled by tune2fs or during
mkfs.ext4

Acked-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
@kvaneesh
ext4: Add Ext4 compat richacl feature flag
e17ad31 
This feature flag can be used to enable richacl on
the file system. Once enabled the "acl" mount option
will enable richacl instead of posix acl

Acked-by: J. Bruce Fields <bfields@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
@kvaneesh
ext4: Add temporary richacl mount option for ext4
13fc237 
This helps in easy testing of the patchset. The mount
option will be later removed in favour of a feature flag.

***Should be folded before merging***

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
hauke pushed a commit to hauke/linux that referenced this pull request Jul 28, 2014
@bp3tk0v
x86/boot: Further compress CPUs bootup message
a17bce4 
Turn it into (for example):

[    0.073380] x86: Booting SMP configuration:
[    0.074005] .... node   #0, CPUs:          #1   #2   #3   #4   #5   torvalds#6   torvalds#7
[    0.603005] .... node   #1, CPUs:     torvalds#8   torvalds#9  torvalds#10  torvalds#11  torvalds#12  torvalds#13  torvalds#14  torvalds#15
[    1.200005] .... node   #2, CPUs:    torvalds#16  torvalds#17  torvalds#18  torvalds#19  torvalds#20  torvalds#21  torvalds#22  torvalds#23
[    1.796005] .... node   #3, CPUs:    torvalds#24  torvalds#25  torvalds#26  torvalds#27  torvalds#28  torvalds#29  torvalds#30  torvalds#31
[    2.393005] .... node   #4, CPUs:    torvalds#32  torvalds#33  torvalds#34  torvalds#35  torvalds#36  torvalds#37  torvalds#38  torvalds#39
[    2.996005] .... node   #5, CPUs:    torvalds#40  torvalds#41  torvalds#42  torvalds#43  torvalds#44  torvalds#45  torvalds#46  torvalds#47
[    3.600005] .... node   torvalds#6, CPUs:    torvalds#48  torvalds#49  torvalds#50  torvalds#51  #52  #53  torvalds#54  torvalds#55
[    4.202005] .... node   torvalds#7, CPUs:    torvalds#56  torvalds#57  #58  torvalds#59  torvalds#60  torvalds#61  torvalds#62  torvalds#63
[    4.811005] .... node   torvalds#8, CPUs:    torvalds#64  torvalds#65  torvalds#66  torvalds#67  torvalds#68  torvalds#69  #70  torvalds#71
[    5.421006] .... node   torvalds#9, CPUs:    torvalds#72  torvalds#73  torvalds#74  torvalds#75  torvalds#76  torvalds#77  torvalds#78  torvalds#79
[    6.032005] .... node  torvalds#10, CPUs:    torvalds#80  torvalds#81  torvalds#82  torvalds#83  torvalds#84  torvalds#85  torvalds#86  torvalds#87
[    6.648006] .... node  torvalds#11, CPUs:    torvalds#88  torvalds#89  torvalds#90  torvalds#91  torvalds#92  torvalds#93  torvalds#94  torvalds#95
[    7.262005] .... node  torvalds#12, CPUs:    torvalds#96  torvalds#97  torvalds#98  torvalds#99 torvalds#100 torvalds#101 torvalds#102 torvalds#103
[    7.865005] .... node  torvalds#13, CPUs:   torvalds#104 torvalds#105 torvalds#106 torvalds#107 torvalds#108 torvalds#109 torvalds#110 torvalds#111
[    8.466005] .... node  torvalds#14, CPUs:   torvalds#112 torvalds#113 torvalds#114 torvalds#115 torvalds#116 torvalds#117 torvalds#118 torvalds#119
[    9.073006] .... node  torvalds#15, CPUs:   torvalds#120 torvalds#121 torvalds#122 torvalds#123 torvalds#124 torvalds#125 torvalds#126 torvalds#127
[    9.679901] x86: Booted up 16 nodes, 128 CPUs

and drop useless elements.

Change num_digits() to hpa's division-avoiding, cell-phone-typed
version which he went at great lengths and pains to submit on a
Saturday evening.

Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: huawei.libin@huawei.com
Cc: wangyijing@huawei.com
Cc: fenghua.yu@intel.com
Cc: guohanjun@huawei.com
Cc: paul.gortmaker@windriver.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20130930095624.GB16383@pd.tnic
Signed-off-by: Ingo Molnar <mingo@kernel.org>
@rosellef rosellef closed this Jul 29, 2014
tobetter pushed a commit to tobetter/linux that referenced this pull request Sep 22, 2015
@mdrjr
Merge pull request torvalds#109 from umiddelb/odroidc-3.10.y
90a0b3a 
(re-) added Docker support
johnhubbard added a commit to johnhubbard/linux that referenced this pull request Jun 30, 2023
@johnhubbard
mm/hugetlb.c: fix a bug within a BUG(): inconsistent pte comparison
9a31656 
The following crash happens for me when running the -mm selftests
(below). Specifically, it happens while running the uffd-stress
subtests:

kernel BUG at mm/hugetlb.c:7249!
invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
CPU: 0 PID: 3238 Comm: uffd-stress Not tainted 6.4.0-hubbard-github+ torvalds#109
Hardware name: ASUS X299-A/PRIME X299-A, BIOS 1503 08/03/2018
RIP: 0010:huge_pte_alloc+0x12c/0x1a0
...
Call Trace:
 <TASK>
 ? __die_body+0x63/0xb0
 ? die+0x9f/0xc0
 ? do_trap+0xab/0x180
 ? huge_pte_alloc+0x12c/0x1a0
 ? do_error_trap+0xc6/0x110
 ? huge_pte_alloc+0x12c/0x1a0
 ? handle_invalid_op+0x2c/0x40
 ? huge_pte_alloc+0x12c/0x1a0
 ? exc_invalid_op+0x33/0x50
 ? asm_exc_invalid_op+0x16/0x20
 ? __pfx_put_prev_task_idle+0x10/0x10
 ? huge_pte_alloc+0x12c/0x1a0
 hugetlb_fault+0x1a3/0x1120
 ? finish_task_switch+0xb3/0x2a0
 ? lock_is_held_type+0xdb/0x150
 handle_mm_fault+0xb8a/0xd40
 ? find_vma+0x5d/0xa0
 do_user_addr_fault+0x257/0x5d0
 exc_page_fault+0x7b/0x1f0
 asm_exc_page_fault+0x22/0x30

That happens because a BUG() statement in huge_pte_alloc() attempts to
check that a pte, if present, is a hugetlb pte, but it does so in a
non-lockless-safe manner that leads to a false BUG() report.

We got here due to a couple of bugs, each of which by itself was not
quite enough to cause a problem:

First of all, before commit c33c794("mm: ptep_get() conversion"),
the BUG() statement in huge_pte_alloc() was itself fragile: it relied
upon compiler behavior to only read the pte once, despite using it twice
in the same conditional.

Next, commit c33c794 ("mm: ptep_get() conversion") broke that
delicate situation, by causing all direct pte reads to be done via
READ_ONCE(). And so READ_ONCE() got called twice within the same BUG()
conditional, leading to comparing (potentially, occasionally) different
versions of the pte, and thus to false BUG() reports.

Now, that commit is only partially to blame here but, people doing
bisections will invariably land there, so this will help them find a fix
for a real crash. And also, the previous behavior was unlikely to ever
expose this bug--it was fragile, yet not actually broken.

So that's why I chose this commit for the Fixes tag, rather than the
commit that created the original BUG() statement.

Fixes: c33c794 ("mm: ptep_get() conversion")
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Yu Zhao <yuzhao@google.com>
johnhubbard added a commit to johnhubbard/linux that referenced this pull request Jun 30, 2023
@johnhubbard
mm/hugetlb.c: fix a bug within a BUG(): inconsistent pte comparison
bb4aeaa 
The following crash happens for me when running the -mm selftests
(below). Specifically, it happens while running the uffd-stress
subtests:

kernel BUG at mm/hugetlb.c:7249!
invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
CPU: 0 PID: 3238 Comm: uffd-stress Not tainted 6.4.0-hubbard-github+ torvalds#109
Hardware name: ASUS X299-A/PRIME X299-A, BIOS 1503 08/03/2018
RIP: 0010:huge_pte_alloc+0x12c/0x1a0
...
Call Trace:
 <TASK>
 ? __die_body+0x63/0xb0
 ? die+0x9f/0xc0
 ? do_trap+0xab/0x180
 ? huge_pte_alloc+0x12c/0x1a0
 ? do_error_trap+0xc6/0x110
 ? huge_pte_alloc+0x12c/0x1a0
 ? handle_invalid_op+0x2c/0x40
 ? huge_pte_alloc+0x12c/0x1a0
 ? exc_invalid_op+0x33/0x50
 ? asm_exc_invalid_op+0x16/0x20
 ? __pfx_put_prev_task_idle+0x10/0x10
 ? huge_pte_alloc+0x12c/0x1a0
 hugetlb_fault+0x1a3/0x1120
 ? finish_task_switch+0xb3/0x2a0
 ? lock_is_held_type+0xdb/0x150
 handle_mm_fault+0xb8a/0xd40
 ? find_vma+0x5d/0xa0
 do_user_addr_fault+0x257/0x5d0
 exc_page_fault+0x7b/0x1f0
 asm_exc_page_fault+0x22/0x30

That happens because a BUG() statement in huge_pte_alloc() attempts to
check that a pte, if present, is a hugetlb pte, but it does so in a
non-lockless-safe manner that leads to a false BUG() report.

We got here due to a couple of bugs, each of which by itself was not
quite enough to cause a problem:

First of all, before commit c33c794("mm: ptep_get() conversion"),
the BUG() statement in huge_pte_alloc() was itself fragile: it relied
upon compiler behavior to only read the pte once, despite using it twice
in the same conditional.

Next, commit c33c794 ("mm: ptep_get() conversion") broke that
delicate situation, by causing all direct pte reads to be done via
READ_ONCE(). And so READ_ONCE() got called twice within the same BUG()
conditional, leading to comparing (potentially, occasionally) different
versions of the pte, and thus to false BUG() reports.

Now, that commit is only partially to blame here but, people doing
bisections will invariably land there, so this will help them find a fix
for a real crash. And also, the previous behavior was unlikely to ever
expose this bug--it was fragile, yet not actually broken.

So that's why I chose this commit for the Fixes tag, rather than the
commit that created the original BUG() statement.

Fixes: c33c794 ("mm: ptep_get() conversion")
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Yu Zhao <yuzhao@google.com>
johnhubbard added a commit to johnhubbard/linux that referenced this pull request Jun 30, 2023
@johnhubbard
mm/hugetlb.c: fix a bug within a BUG(): inconsistent pte comparison
4fad50c 
The following crash happens for me when running the -mm selftests
(below). Specifically, it happens while running the uffd-stress
subtests:

kernel BUG at mm/hugetlb.c:7249!
invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
CPU: 0 PID: 3238 Comm: uffd-stress Not tainted 6.4.0-hubbard-github+ torvalds#109
Hardware name: ASUS X299-A/PRIME X299-A, BIOS 1503 08/03/2018
RIP: 0010:huge_pte_alloc+0x12c/0x1a0
...
Call Trace:
 <TASK>
 ? __die_body+0x63/0xb0
 ? die+0x9f/0xc0
 ? do_trap+0xab/0x180
 ? huge_pte_alloc+0x12c/0x1a0
 ? do_error_trap+0xc6/0x110
 ? huge_pte_alloc+0x12c/0x1a0
 ? handle_invalid_op+0x2c/0x40
 ? huge_pte_alloc+0x12c/0x1a0
 ? exc_invalid_op+0x33/0x50
 ? asm_exc_invalid_op+0x16/0x20
 ? __pfx_put_prev_task_idle+0x10/0x10
 ? huge_pte_alloc+0x12c/0x1a0
 hugetlb_fault+0x1a3/0x1120
 ? finish_task_switch+0xb3/0x2a0
 ? lock_is_held_type+0xdb/0x150
 handle_mm_fault+0xb8a/0xd40
 ? find_vma+0x5d/0xa0
 do_user_addr_fault+0x257/0x5d0
 exc_page_fault+0x7b/0x1f0
 asm_exc_page_fault+0x22/0x30

That happens because a BUG() statement in huge_pte_alloc() attempts to
check that a pte, if present, is a hugetlb pte, but it does so in a
non-lockless-safe manner that leads to a false BUG() report.

We got here due to a couple of bugs, each of which by itself was not
quite enough to cause a problem:

First of all, before commit c33c794("mm: ptep_get() conversion"),
the BUG() statement in huge_pte_alloc() was itself fragile: it relied
upon compiler behavior to only read the pte once, despite using it twice
in the same conditional.

Next, commit c33c794 ("mm: ptep_get() conversion") broke that
delicate situation, by causing all direct pte reads to be done via
READ_ONCE(). And so READ_ONCE() got called twice within the same BUG()
conditional, leading to comparing (potentially, occasionally) different
versions of the pte, and thus to false BUG() reports.

Fix this by taking a single snapshot of the pte before using it in the
BUG conditional.

Now, that commit is only partially to blame here but, people doing
bisections will invariably land there, so this will help them find a fix
for a real crash. And also, the previous behavior was unlikely to ever
expose this bug--it was fragile, yet not actually broken.

So that's why I chose this commit for the Fixes tag, rather than the
commit that created the original BUG() statement.

Fixes: c33c794 ("mm: ptep_get() conversion")
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Yu Zhao <yuzhao@google.com>
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this pull request Jun 30, 2023
@johnhubbard @intel-lab-lkp
mm/hugetlb.c: fix a bug within a BUG(): inconsistent pte comparison
2e10052 
The following crash happens for me when running the -mm selftests
(below). Specifically, it happens while running the uffd-stress
subtests:

kernel BUG at mm/hugetlb.c:7249!
invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
CPU: 0 PID: 3238 Comm: uffd-stress Not tainted 6.4.0-hubbard-github+ torvalds#109
Hardware name: ASUS X299-A/PRIME X299-A, BIOS 1503 08/03/2018
RIP: 0010:huge_pte_alloc+0x12c/0x1a0
...
Call Trace:
 <TASK>
 ? __die_body+0x63/0xb0
 ? die+0x9f/0xc0
 ? do_trap+0xab/0x180
 ? huge_pte_alloc+0x12c/0x1a0
 ? do_error_trap+0xc6/0x110
 ? huge_pte_alloc+0x12c/0x1a0
 ? handle_invalid_op+0x2c/0x40
 ? huge_pte_alloc+0x12c/0x1a0
 ? exc_invalid_op+0x33/0x50
 ? asm_exc_invalid_op+0x16/0x20
 ? __pfx_put_prev_task_idle+0x10/0x10
 ? huge_pte_alloc+0x12c/0x1a0
 hugetlb_fault+0x1a3/0x1120
 ? finish_task_switch+0xb3/0x2a0
 ? lock_is_held_type+0xdb/0x150
 handle_mm_fault+0xb8a/0xd40
 ? find_vma+0x5d/0xa0
 do_user_addr_fault+0x257/0x5d0
 exc_page_fault+0x7b/0x1f0
 asm_exc_page_fault+0x22/0x30

That happens because a BUG() statement in huge_pte_alloc() attempts to
check that a pte, if present, is a hugetlb pte, but it does so in a
non-lockless-safe manner that leads to a false BUG() report.

We got here due to a couple of bugs, each of which by itself was not
quite enough to cause a problem:

First of all, before commit c33c794("mm: ptep_get() conversion"),
the BUG() statement in huge_pte_alloc() was itself fragile: it relied
upon compiler behavior to only read the pte once, despite using it twice
in the same conditional.

Next, commit c33c794 ("mm: ptep_get() conversion") broke that
delicate situation, by causing all direct pte reads to be done via
READ_ONCE(). And so READ_ONCE() got called twice within the same BUG()
conditional, leading to comparing (potentially, occasionally) different
versions of the pte, and thus to false BUG() reports.

Fix this by taking a single snapshot of the pte before using it in the
BUG conditional.

Now, that commit is only partially to blame here but, people doing
bisections will invariably land there, so this will help them find a fix
for a real crash. And also, the previous behavior was unlikely to ever
expose this bug--it was fragile, yet not actually broken.

So that's why I chose this commit for the Fixes tag, rather than the
commit that created the original BUG() statement.

Fixes: c33c794 ("mm: ptep_get() conversion")
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
johnhubbard added a commit to johnhubbard/linux that referenced this pull request Jul 1, 2023
@johnhubbard
mm/hugetlb.c: fix a bug within a BUG(): inconsistent pte comparison
dda8499 
The following crash happens for me when running the -mm selftests
(below). Specifically, it happens while running the uffd-stress
subtests:

kernel BUG at mm/hugetlb.c:7249!
invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
CPU: 0 PID: 3238 Comm: uffd-stress Not tainted 6.4.0-hubbard-github+ torvalds#109
Hardware name: ASUS X299-A/PRIME X299-A, BIOS 1503 08/03/2018
RIP: 0010:huge_pte_alloc+0x12c/0x1a0
...
Call Trace:
 <TASK>
 ? __die_body+0x63/0xb0
 ? die+0x9f/0xc0
 ? do_trap+0xab/0x180
 ? huge_pte_alloc+0x12c/0x1a0
 ? do_error_trap+0xc6/0x110
 ? huge_pte_alloc+0x12c/0x1a0
 ? handle_invalid_op+0x2c/0x40
 ? huge_pte_alloc+0x12c/0x1a0
 ? exc_invalid_op+0x33/0x50
 ? asm_exc_invalid_op+0x16/0x20
 ? __pfx_put_prev_task_idle+0x10/0x10
 ? huge_pte_alloc+0x12c/0x1a0
 hugetlb_fault+0x1a3/0x1120
 ? finish_task_switch+0xb3/0x2a0
 ? lock_is_held_type+0xdb/0x150
 handle_mm_fault+0xb8a/0xd40
 ? find_vma+0x5d/0xa0
 do_user_addr_fault+0x257/0x5d0
 exc_page_fault+0x7b/0x1f0
 asm_exc_page_fault+0x22/0x30

That happens because a BUG() statement in huge_pte_alloc() attempts to
check that a pte, if present, is a hugetlb pte, but it does so in a
non-lockless-safe manner that leads to a false BUG() report.

We got here due to a couple of bugs, each of which by itself was not
quite enough to cause a problem:

First of all, before commit c33c794("mm: ptep_get() conversion"),
the BUG() statement in huge_pte_alloc() was itself fragile: it relied
upon compiler behavior to only read the pte once, despite using it twice
in the same conditional.

Next, commit c33c794 ("mm: ptep_get() conversion") broke that
delicate situation, by causing all direct pte reads to be done via
READ_ONCE(). And so READ_ONCE() got called twice within the same BUG()
conditional, leading to comparing (potentially, occasionally) different
versions of the pte, and thus to false BUG() reports.

Fix this by taking a single snapshot of the pte before using it in the
BUG conditional.

Now, that commit is only partially to blame here but, people doing
bisections will invariably land there, so this will help them find a fix
for a real crash. And also, the previous behavior was unlikely to ever
expose this bug--it was fragile, yet not actually broken.

So that's why I chose this commit for the Fixes tag, rather than the
commit that created the original BUG() statement.

Fixes: c33c794 ("mm: ptep_get() conversion")
Acked-by: James Houghton <jthoughton@google.com>
Acked-by: Muchun Song <songmuchun@bytedance.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Yu Zhao <yuzhao@google.com>
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this pull request Jul 1, 2023
@johnhubbard @intel-lab-lkp
mm/hugetlb.c: fix a bug within a BUG(): inconsistent pte comparison
b47be88 
The following crash happens for me when running the -mm selftests
(below). Specifically, it happens while running the uffd-stress
subtests:

kernel BUG at mm/hugetlb.c:7249!
invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
CPU: 0 PID: 3238 Comm: uffd-stress Not tainted 6.4.0-hubbard-github+ torvalds#109
Hardware name: ASUS X299-A/PRIME X299-A, BIOS 1503 08/03/2018
RIP: 0010:huge_pte_alloc+0x12c/0x1a0
...
Call Trace:
 <TASK>
 ? __die_body+0x63/0xb0
 ? die+0x9f/0xc0
 ? do_trap+0xab/0x180
 ? huge_pte_alloc+0x12c/0x1a0
 ? do_error_trap+0xc6/0x110
 ? huge_pte_alloc+0x12c/0x1a0
 ? handle_invalid_op+0x2c/0x40
 ? huge_pte_alloc+0x12c/0x1a0
 ? exc_invalid_op+0x33/0x50
 ? asm_exc_invalid_op+0x16/0x20
 ? __pfx_put_prev_task_idle+0x10/0x10
 ? huge_pte_alloc+0x12c/0x1a0
 hugetlb_fault+0x1a3/0x1120
 ? finish_task_switch+0xb3/0x2a0
 ? lock_is_held_type+0xdb/0x150
 handle_mm_fault+0xb8a/0xd40
 ? find_vma+0x5d/0xa0
 do_user_addr_fault+0x257/0x5d0
 exc_page_fault+0x7b/0x1f0
 asm_exc_page_fault+0x22/0x30

That happens because a BUG() statement in huge_pte_alloc() attempts to
check that a pte, if present, is a hugetlb pte, but it does so in a
non-lockless-safe manner that leads to a false BUG() report.

We got here due to a couple of bugs, each of which by itself was not
quite enough to cause a problem:

First of all, before commit c33c794("mm: ptep_get() conversion"),
the BUG() statement in huge_pte_alloc() was itself fragile: it relied
upon compiler behavior to only read the pte once, despite using it twice
in the same conditional.

Next, commit c33c794 ("mm: ptep_get() conversion") broke that
delicate situation, by causing all direct pte reads to be done via
READ_ONCE(). And so READ_ONCE() got called twice within the same BUG()
conditional, leading to comparing (potentially, occasionally) different
versions of the pte, and thus to false BUG() reports.

Fix this by taking a single snapshot of the pte before using it in the
BUG conditional.

Now, that commit is only partially to blame here but, people doing
bisections will invariably land there, so this will help them find a fix
for a real crash. And also, the previous behavior was unlikely to ever
expose this bug--it was fragile, yet not actually broken.

So that's why I chose this commit for the Fixes tag, rather than the
commit that created the original BUG() statement.

Fixes: c33c794 ("mm: ptep_get() conversion")
Acked-by: James Houghton <jthoughton@google.com>
Acked-by: Muchun Song <songmuchun@bytedance.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this pull request Jul 3, 2023
@johnhubbard @akpm00
mm/hugetlb.c: fix a bug within a BUG(): inconsistent pte comparison
59709c6 
The following crash happens for me when running the -mm selftests (below).
Specifically, it happens while running the uffd-stress subtests:

kernel BUG at mm/hugetlb.c:7249!
invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
CPU: 0 PID: 3238 Comm: uffd-stress Not tainted 6.4.0-hubbard-github+ torvalds#109
Hardware name: ASUS X299-A/PRIME X299-A, BIOS 1503 08/03/2018
RIP: 0010:huge_pte_alloc+0x12c/0x1a0
...
Call Trace:
 <TASK>
 ? __die_body+0x63/0xb0
 ? die+0x9f/0xc0
 ? do_trap+0xab/0x180
 ? huge_pte_alloc+0x12c/0x1a0
 ? do_error_trap+0xc6/0x110
 ? huge_pte_alloc+0x12c/0x1a0
 ? handle_invalid_op+0x2c/0x40
 ? huge_pte_alloc+0x12c/0x1a0
 ? exc_invalid_op+0x33/0x50
 ? asm_exc_invalid_op+0x16/0x20
 ? __pfx_put_prev_task_idle+0x10/0x10
 ? huge_pte_alloc+0x12c/0x1a0
 hugetlb_fault+0x1a3/0x1120
 ? finish_task_switch+0xb3/0x2a0
 ? lock_is_held_type+0xdb/0x150
 handle_mm_fault+0xb8a/0xd40
 ? find_vma+0x5d/0xa0
 do_user_addr_fault+0x257/0x5d0
 exc_page_fault+0x7b/0x1f0
 asm_exc_page_fault+0x22/0x30

That happens because a BUG() statement in huge_pte_alloc() attempts to
check that a pte, if present, is a hugetlb pte, but it does so in a
non-lockless-safe manner that leads to a false BUG() report.

We got here due to a couple of bugs, each of which by itself was not quite
enough to cause a problem:

First of all, before commit c33c794("mm: ptep_get() conversion"), the
BUG() statement in huge_pte_alloc() was itself fragile: it relied upon
compiler behavior to only read the pte once, despite using it twice in the
same conditional.

Next, commit c33c794 ("mm: ptep_get() conversion") broke that
delicate situation, by causing all direct pte reads to be done via
READ_ONCE().  And so READ_ONCE() got called twice within the same BUG()
conditional, leading to comparing (potentially, occasionally) different
versions of the pte, and thus to false BUG() reports.

Fix this by taking a single snapshot of the pte before using it in the
BUG conditional.

Now, that commit is only partially to blame here but, people doing
bisections will invariably land there, so this will help them find a fix
for a real crash.  And also, the previous behavior was unlikely to ever
expose this bug--it was fragile, yet not actually broken.

So that's why I chose this commit for the Fixes tag, rather than the
commit that created the original BUG() statement.

Link: https://lkml.kernel.org/r/20230701010442.2041858-1-jhubbard@nvidia.com
Fixes: c33c794 ("mm: ptep_get() conversion")
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: James Houghton <jthoughton@google.com>
Acked-by: Muchun Song <songmuchun@bytedance.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this pull request Jul 3, 2023
@johnhubbard @akpm00
mm/hugetlb.c: fix a bug within a BUG(): inconsistent pte comparison
4e41c21 
The following crash happens for me when running the -mm selftests (below).
Specifically, it happens while running the uffd-stress subtests:

kernel BUG at mm/hugetlb.c:7249!
invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
CPU: 0 PID: 3238 Comm: uffd-stress Not tainted 6.4.0-hubbard-github+ torvalds#109
Hardware name: ASUS X299-A/PRIME X299-A, BIOS 1503 08/03/2018
RIP: 0010:huge_pte_alloc+0x12c/0x1a0
...
Call Trace:
 <TASK>
 ? __die_body+0x63/0xb0
 ? die+0x9f/0xc0
 ? do_trap+0xab/0x180
 ? huge_pte_alloc+0x12c/0x1a0
 ? do_error_trap+0xc6/0x110
 ? huge_pte_alloc+0x12c/0x1a0
 ? handle_invalid_op+0x2c/0x40
 ? huge_pte_alloc+0x12c/0x1a0
 ? exc_invalid_op+0x33/0x50
 ? asm_exc_invalid_op+0x16/0x20
 ? __pfx_put_prev_task_idle+0x10/0x10
 ? huge_pte_alloc+0x12c/0x1a0
 hugetlb_fault+0x1a3/0x1120
 ? finish_task_switch+0xb3/0x2a0
 ? lock_is_held_type+0xdb/0x150
 handle_mm_fault+0xb8a/0xd40
 ? find_vma+0x5d/0xa0
 do_user_addr_fault+0x257/0x5d0
 exc_page_fault+0x7b/0x1f0
 asm_exc_page_fault+0x22/0x30

That happens because a BUG() statement in huge_pte_alloc() attempts to
check that a pte, if present, is a hugetlb pte, but it does so in a
non-lockless-safe manner that leads to a false BUG() report.

We got here due to a couple of bugs, each of which by itself was not quite
enough to cause a problem:

First of all, before commit c33c794("mm: ptep_get() conversion"), the
BUG() statement in huge_pte_alloc() was itself fragile: it relied upon
compiler behavior to only read the pte once, despite using it twice in the
same conditional.

Next, commit c33c794 ("mm: ptep_get() conversion") broke that
delicate situation, by causing all direct pte reads to be done via
READ_ONCE().  And so READ_ONCE() got called twice within the same BUG()
conditional, leading to comparing (potentially, occasionally) different
versions of the pte, and thus to false BUG() reports.

Fix this by taking a single snapshot of the pte before using it in the
BUG conditional.

Now, that commit is only partially to blame here but, people doing
bisections will invariably land there, so this will help them find a fix
for a real crash.  And also, the previous behavior was unlikely to ever
expose this bug--it was fragile, yet not actually broken.

So that's why I chose this commit for the Fixes tag, rather than the
commit that created the original BUG() statement.

Link: https://lkml.kernel.org/r/20230701010442.2041858-1-jhubbard@nvidia.com
Fixes: c33c794 ("mm: ptep_get() conversion")
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: James Houghton <jthoughton@google.com>
Acked-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: SeongJae Park <sj@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this pull request Jul 4, 2023
@johnhubbard @akpm00
mm/hugetlb.c: fix a bug within a BUG(): inconsistent pte comparison
6267acb 
The following crash happens for me when running the -mm selftests (below).
Specifically, it happens while running the uffd-stress subtests:

kernel BUG at mm/hugetlb.c:7249!
invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
CPU: 0 PID: 3238 Comm: uffd-stress Not tainted 6.4.0-hubbard-github+ torvalds#109
Hardware name: ASUS X299-A/PRIME X299-A, BIOS 1503 08/03/2018
RIP: 0010:huge_pte_alloc+0x12c/0x1a0
...
Call Trace:
 <TASK>
 ? __die_body+0x63/0xb0
 ? die+0x9f/0xc0
 ? do_trap+0xab/0x180
 ? huge_pte_alloc+0x12c/0x1a0
 ? do_error_trap+0xc6/0x110
 ? huge_pte_alloc+0x12c/0x1a0
 ? handle_invalid_op+0x2c/0x40
 ? huge_pte_alloc+0x12c/0x1a0
 ? exc_invalid_op+0x33/0x50
 ? asm_exc_invalid_op+0x16/0x20
 ? __pfx_put_prev_task_idle+0x10/0x10
 ? huge_pte_alloc+0x12c/0x1a0
 hugetlb_fault+0x1a3/0x1120
 ? finish_task_switch+0xb3/0x2a0
 ? lock_is_held_type+0xdb/0x150
 handle_mm_fault+0xb8a/0xd40
 ? find_vma+0x5d/0xa0
 do_user_addr_fault+0x257/0x5d0
 exc_page_fault+0x7b/0x1f0
 asm_exc_page_fault+0x22/0x30

That happens because a BUG() statement in huge_pte_alloc() attempts to
check that a pte, if present, is a hugetlb pte, but it does so in a
non-lockless-safe manner that leads to a false BUG() report.

We got here due to a couple of bugs, each of which by itself was not quite
enough to cause a problem:

First of all, before commit c33c794("mm: ptep_get() conversion"), the
BUG() statement in huge_pte_alloc() was itself fragile: it relied upon
compiler behavior to only read the pte once, despite using it twice in the
same conditional.

Next, commit c33c794 ("mm: ptep_get() conversion") broke that
delicate situation, by causing all direct pte reads to be done via
READ_ONCE().  And so READ_ONCE() got called twice within the same BUG()
conditional, leading to comparing (potentially, occasionally) different
versions of the pte, and thus to false BUG() reports.

Fix this by taking a single snapshot of the pte before using it in the
BUG conditional.

Now, that commit is only partially to blame here but, people doing
bisections will invariably land there, so this will help them find a fix
for a real crash.  And also, the previous behavior was unlikely to ever
expose this bug--it was fragile, yet not actually broken.

So that's why I chose this commit for the Fixes tag, rather than the
commit that created the original BUG() statement.

Link: https://lkml.kernel.org/r/20230701010442.2041858-1-jhubbard@nvidia.com
Fixes: c33c794 ("mm: ptep_get() conversion")
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: James Houghton <jthoughton@google.com>
Acked-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: SeongJae Park <sj@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
akiyks pushed a commit to akiyks/linux that referenced this pull request Jul 6, 2023
@johnhubbard @akpm00
mm/hugetlb.c: fix a bug within a BUG(): inconsistent pte comparison
98afd62 
The following crash happens for me when running the -mm selftests (below).
Specifically, it happens while running the uffd-stress subtests:

kernel BUG at mm/hugetlb.c:7249!
invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
CPU: 0 PID: 3238 Comm: uffd-stress Not tainted 6.4.0-hubbard-github+ torvalds#109
Hardware name: ASUS X299-A/PRIME X299-A, BIOS 1503 08/03/2018
RIP: 0010:huge_pte_alloc+0x12c/0x1a0
...
Call Trace:
 <TASK>
 ? __die_body+0x63/0xb0
 ? die+0x9f/0xc0
 ? do_trap+0xab/0x180
 ? huge_pte_alloc+0x12c/0x1a0
 ? do_error_trap+0xc6/0x110
 ? huge_pte_alloc+0x12c/0x1a0
 ? handle_invalid_op+0x2c/0x40
 ? huge_pte_alloc+0x12c/0x1a0
 ? exc_invalid_op+0x33/0x50
 ? asm_exc_invalid_op+0x16/0x20
 ? __pfx_put_prev_task_idle+0x10/0x10
 ? huge_pte_alloc+0x12c/0x1a0
 hugetlb_fault+0x1a3/0x1120
 ? finish_task_switch+0xb3/0x2a0
 ? lock_is_held_type+0xdb/0x150
 handle_mm_fault+0xb8a/0xd40
 ? find_vma+0x5d/0xa0
 do_user_addr_fault+0x257/0x5d0
 exc_page_fault+0x7b/0x1f0
 asm_exc_page_fault+0x22/0x30

That happens because a BUG() statement in huge_pte_alloc() attempts to
check that a pte, if present, is a hugetlb pte, but it does so in a
non-lockless-safe manner that leads to a false BUG() report.

We got here due to a couple of bugs, each of which by itself was not quite
enough to cause a problem:

First of all, before commit c33c794("mm: ptep_get() conversion"), the
BUG() statement in huge_pte_alloc() was itself fragile: it relied upon
compiler behavior to only read the pte once, despite using it twice in the
same conditional.

Next, commit c33c794 ("mm: ptep_get() conversion") broke that
delicate situation, by causing all direct pte reads to be done via
READ_ONCE().  And so READ_ONCE() got called twice within the same BUG()
conditional, leading to comparing (potentially, occasionally) different
versions of the pte, and thus to false BUG() reports.

Fix this by taking a single snapshot of the pte before using it in the
BUG conditional.

Now, that commit is only partially to blame here but, people doing
bisections will invariably land there, so this will help them find a fix
for a real crash.  And also, the previous behavior was unlikely to ever
expose this bug--it was fragile, yet not actually broken.

So that's why I chose this commit for the Fixes tag, rather than the
commit that created the original BUG() statement.

Link: https://lkml.kernel.org/r/20230701010442.2041858-1-jhubbard@nvidia.com
Fixes: c33c794 ("mm: ptep_get() conversion")
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: James Houghton <jthoughton@google.com>
Acked-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: SeongJae Park <sj@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
akiyks pushed a commit to akiyks/linux that referenced this pull request Jul 7, 2023
@johnhubbard @akpm00
mm/hugetlb.c: fix a bug within a BUG(): inconsistent pte comparison
610f8be 
The following crash happens for me when running the -mm selftests (below).
Specifically, it happens while running the uffd-stress subtests:

kernel BUG at mm/hugetlb.c:7249!
invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
CPU: 0 PID: 3238 Comm: uffd-stress Not tainted 6.4.0-hubbard-github+ torvalds#109
Hardware name: ASUS X299-A/PRIME X299-A, BIOS 1503 08/03/2018
RIP: 0010:huge_pte_alloc+0x12c/0x1a0
...
Call Trace:
 <TASK>
 ? __die_body+0x63/0xb0
 ? die+0x9f/0xc0
 ? do_trap+0xab/0x180
 ? huge_pte_alloc+0x12c/0x1a0
 ? do_error_trap+0xc6/0x110
 ? huge_pte_alloc+0x12c/0x1a0
 ? handle_invalid_op+0x2c/0x40
 ? huge_pte_alloc+0x12c/0x1a0
 ? exc_invalid_op+0x33/0x50
 ? asm_exc_invalid_op+0x16/0x20
 ? __pfx_put_prev_task_idle+0x10/0x10
 ? huge_pte_alloc+0x12c/0x1a0
 hugetlb_fault+0x1a3/0x1120
 ? finish_task_switch+0xb3/0x2a0
 ? lock_is_held_type+0xdb/0x150
 handle_mm_fault+0xb8a/0xd40
 ? find_vma+0x5d/0xa0
 do_user_addr_fault+0x257/0x5d0
 exc_page_fault+0x7b/0x1f0
 asm_exc_page_fault+0x22/0x30

That happens because a BUG() statement in huge_pte_alloc() attempts to
check that a pte, if present, is a hugetlb pte, but it does so in a
non-lockless-safe manner that leads to a false BUG() report.

We got here due to a couple of bugs, each of which by itself was not quite
enough to cause a problem:

First of all, before commit c33c794("mm: ptep_get() conversion"), the
BUG() statement in huge_pte_alloc() was itself fragile: it relied upon
compiler behavior to only read the pte once, despite using it twice in the
same conditional.

Next, commit c33c794 ("mm: ptep_get() conversion") broke that
delicate situation, by causing all direct pte reads to be done via
READ_ONCE().  And so READ_ONCE() got called twice within the same BUG()
conditional, leading to comparing (potentially, occasionally) different
versions of the pte, and thus to false BUG() reports.

Fix this by taking a single snapshot of the pte before using it in the
BUG conditional.

Now, that commit is only partially to blame here but, people doing
bisections will invariably land there, so this will help them find a fix
for a real crash.  And also, the previous behavior was unlikely to ever
expose this bug--it was fragile, yet not actually broken.

So that's why I chose this commit for the Fixes tag, rather than the
commit that created the original BUG() statement.

Link: https://lkml.kernel.org/r/20230701010442.2041858-1-jhubbard@nvidia.com
Fixes: c33c794 ("mm: ptep_get() conversion")
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: James Houghton <jthoughton@google.com>
Acked-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: SeongJae Park <sj@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
torvalds pushed a commit that referenced this pull request Jul 8, 2023
@johnhubbard @akpm00
mm/hugetlb.c: fix a bug within a BUG(): inconsistent pte comparison
191fcdb 
The following crash happens for me when running the -mm selftests (below).
Specifically, it happens while running the uffd-stress subtests:

kernel BUG at mm/hugetlb.c:7249!
invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
CPU: 0 PID: 3238 Comm: uffd-stress Not tainted 6.4.0-hubbard-github+ #109
Hardware name: ASUS X299-A/PRIME X299-A, BIOS 1503 08/03/2018
RIP: 0010:huge_pte_alloc+0x12c/0x1a0
...
Call Trace:
 <TASK>
 ? __die_body+0x63/0xb0
 ? die+0x9f/0xc0
 ? do_trap+0xab/0x180
 ? huge_pte_alloc+0x12c/0x1a0
 ? do_error_trap+0xc6/0x110
 ? huge_pte_alloc+0x12c/0x1a0
 ? handle_invalid_op+0x2c/0x40
 ? huge_pte_alloc+0x12c/0x1a0
 ? exc_invalid_op+0x33/0x50
 ? asm_exc_invalid_op+0x16/0x20
 ? __pfx_put_prev_task_idle+0x10/0x10
 ? huge_pte_alloc+0x12c/0x1a0
 hugetlb_fault+0x1a3/0x1120
 ? finish_task_switch+0xb3/0x2a0
 ? lock_is_held_type+0xdb/0x150
 handle_mm_fault+0xb8a/0xd40
 ? find_vma+0x5d/0xa0
 do_user_addr_fault+0x257/0x5d0
 exc_page_fault+0x7b/0x1f0
 asm_exc_page_fault+0x22/0x30

That happens because a BUG() statement in huge_pte_alloc() attempts to
check that a pte, if present, is a hugetlb pte, but it does so in a
non-lockless-safe manner that leads to a false BUG() report.

We got here due to a couple of bugs, each of which by itself was not quite
enough to cause a problem:

First of all, before commit c33c794("mm: ptep_get() conversion"), the
BUG() statement in huge_pte_alloc() was itself fragile: it relied upon
compiler behavior to only read the pte once, despite using it twice in the
same conditional.

Next, commit c33c794 ("mm: ptep_get() conversion") broke that
delicate situation, by causing all direct pte reads to be done via
READ_ONCE().  And so READ_ONCE() got called twice within the same BUG()
conditional, leading to comparing (potentially, occasionally) different
versions of the pte, and thus to false BUG() reports.

Fix this by taking a single snapshot of the pte before using it in the
BUG conditional.

Now, that commit is only partially to blame here but, people doing
bisections will invariably land there, so this will help them find a fix
for a real crash.  And also, the previous behavior was unlikely to ever
expose this bug--it was fragile, yet not actually broken.

So that's why I chose this commit for the Fixes tag, rather than the
commit that created the original BUG() statement.

Link: https://lkml.kernel.org/r/20230701010442.2041858-1-jhubbard@nvidia.com
Fixes: c33c794 ("mm: ptep_get() conversion")
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: James Houghton <jthoughton@google.com>
Acked-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: SeongJae Park <sj@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mj22226 pushed a commit to mj22226/linux that referenced this pull request Jul 30, 2023
@vamrs-feng @RadxaStephen
drm/bridge: synopsys: Fix the problem that HDMI sound card is not rec…
27984f4 
…ognized when booting (torvalds#109)

Signed-off-by: Feng Zhang <feng@radxa.com>
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this pull request Dec 25, 2023
@intel-lab-lkp
bpf: Return -ENOTSUPP if callbacks are not allowed in non-JITed programs
e354179 
If CONFIG_BPF_JIT_ALWAYS_ON is not set and bpf_jit_enable is 0, there
exist 6 failed tests.

  [root@linux bpf]# echo 0 > /proc/sys/net/core/bpf_jit_enable
  [root@linux bpf]# ./test_verifier | grep FAIL
  torvalds#107/p inline simple bpf_loop call FAIL
  torvalds#108/p don't inline bpf_loop call, flags non-zero FAIL
  torvalds#109/p don't inline bpf_loop call, callback non-constant FAIL
  torvalds#110/p bpf_loop_inline and a dead func FAIL
  torvalds#111/p bpf_loop_inline stack locations for loop vars FAIL
  torvalds#112/p inline bpf_loop call in a big program FAIL
  Summary: 505 PASSED, 266 SKIPPED, 6 FAILED

The test log shows that callbacks are not allowed in non-JITed programs,
interpreter doesn't support them yet, thus these tests should be skipped
if jit is disabled, just return -ENOTSUPP instead of -EINVAL for pseudo
calls in fixup_call_args().

With this patch:

  [root@linux bpf]# echo 0 > /proc/sys/net/core/bpf_jit_enable
  [root@linux bpf]# ./test_verifier | grep FAIL
  Summary: 505 PASSED, 272 SKIPPED, 0 FAILED

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this pull request Jan 4, 2024
@intel-lab-lkp
bpf: Return -ENOTSUPP if calls are not allowed in non-JITed programs
46792ea 
If CONFIG_BPF_JIT_ALWAYS_ON is not set and bpf_jit_enable is 0, there
exist 6 failed tests.

  [root@linux bpf]# echo 0 > /proc/sys/net/core/bpf_jit_enable
  [root@linux bpf]# echo 0 > /proc/sys/kernel/unprivileged_bpf_disabled
  [root@linux bpf]# ./test_verifier | grep FAIL
  torvalds#106/p inline simple bpf_loop call FAIL
  torvalds#107/p don't inline bpf_loop call, flags non-zero FAIL
  torvalds#108/p don't inline bpf_loop call, callback non-constant FAIL
  torvalds#109/p bpf_loop_inline and a dead func FAIL
  torvalds#110/p bpf_loop_inline stack locations for loop vars FAIL
  torvalds#111/p inline bpf_loop call in a big program FAIL
  Summary: 768 PASSED, 15 SKIPPED, 6 FAILED

The test log shows that callbacks are not allowed in non-JITed programs,
interpreter doesn't support them yet, thus these tests should be skipped
if jit is disabled, just return -ENOTSUPP instead of -EINVAL for pseudo
calls in fixup_call_args().

With this patch:

  [root@linux bpf]# echo 0 > /proc/sys/net/core/bpf_jit_enable
  [root@linux bpf]# echo 0 > /proc/sys/kernel/unprivileged_bpf_disabled
  [root@linux bpf]# ./test_verifier | grep FAIL
  Summary: 768 PASSED, 21 SKIPPED, 0 FAILED

Additionally, as Eduard suggested, return -ENOTSUPP instead of -EINVAL
for the other three places where "non-JITed" is used in error messages
to keep consistent.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this pull request Jan 11, 2024
@intel-lab-lkp
selftests/bpf: Skip callback tests if jit is disabled in test_verifier
67fe510 
If CONFIG_BPF_JIT_ALWAYS_ON is not set and bpf_jit_enable is 0, there
exist 6 failed tests.

  [root@linux bpf]# echo 0 > /proc/sys/net/core/bpf_jit_enable
  [root@linux bpf]# echo 0 > /proc/sys/kernel/unprivileged_bpf_disabled
  [root@linux bpf]# ./test_verifier | grep FAIL
  torvalds#106/p inline simple bpf_loop call FAIL
  torvalds#107/p don't inline bpf_loop call, flags non-zero FAIL
  torvalds#108/p don't inline bpf_loop call, callback non-constant FAIL
  torvalds#109/p bpf_loop_inline and a dead func FAIL
  torvalds#110/p bpf_loop_inline stack locations for loop vars FAIL
  torvalds#111/p inline bpf_loop call in a big program FAIL
  Summary: 768 PASSED, 15 SKIPPED, 6 FAILED

The test log shows that callbacks are not allowed in non-JITed programs,
interpreter doesn't support them yet, thus these tests should be skipped
if jit is disabled, copy some check functions from the other places under
tools directory, and then handle this case in do_test_single().

With this patch:

  [root@linux bpf]# echo 0 > /proc/sys/net/core/bpf_jit_enable
  [root@linux bpf]# echo 0 > /proc/sys/kernel/unprivileged_bpf_disabled
  [root@linux bpf]# ./test_verifier | grep FAIL
  Summary: 768 PASSED, 21 SKIPPED, 0 FAILED

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this pull request Jan 12, 2024
@intel-lab-lkp
selftests/bpf: Skip callback tests if jit is disabled in test_verifier
4448528 
If CONFIG_BPF_JIT_ALWAYS_ON is not set and bpf_jit_enable is 0, there
exist 6 failed tests.

  [root@linux bpf]# echo 0 > /proc/sys/net/core/bpf_jit_enable
  [root@linux bpf]# echo 0 > /proc/sys/kernel/unprivileged_bpf_disabled
  [root@linux bpf]# ./test_verifier | grep FAIL
  torvalds#106/p inline simple bpf_loop call FAIL
  torvalds#107/p don't inline bpf_loop call, flags non-zero FAIL
  torvalds#108/p don't inline bpf_loop call, callback non-constant FAIL
  torvalds#109/p bpf_loop_inline and a dead func FAIL
  torvalds#110/p bpf_loop_inline stack locations for loop vars FAIL
  torvalds#111/p inline bpf_loop call in a big program FAIL
  Summary: 768 PASSED, 15 SKIPPED, 6 FAILED

The test log shows that callbacks are not allowed in non-JITed programs,
interpreter doesn't support them yet, thus these tests should be skipped
if jit is disabled, copy some check functions from the other places under
tools directory, and then handle this case in do_test_single().

With this patch:

  [root@linux bpf]# echo 0 > /proc/sys/net/core/bpf_jit_enable
  [root@linux bpf]# echo 0 > /proc/sys/kernel/unprivileged_bpf_disabled
  [root@linux bpf]# ./test_verifier | grep FAIL
  Summary: 768 PASSED, 21 SKIPPED, 0 FAILED

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this pull request Jan 15, 2024
@intel-lab-lkp
selftests/bpf: Skip callback tests if jit is disabled in test_verifier
edaea8e 
If CONFIG_BPF_JIT_ALWAYS_ON is not set and bpf_jit_enable is 0, there
exist 6 failed tests.

  [root@linux bpf]# echo 0 > /proc/sys/net/core/bpf_jit_enable
  [root@linux bpf]# echo 0 > /proc/sys/kernel/unprivileged_bpf_disabled
  [root@linux bpf]# ./test_verifier | grep FAIL
  torvalds#106/p inline simple bpf_loop call FAIL
  torvalds#107/p don't inline bpf_loop call, flags non-zero FAIL
  torvalds#108/p don't inline bpf_loop call, callback non-constant FAIL
  torvalds#109/p bpf_loop_inline and a dead func FAIL
  torvalds#110/p bpf_loop_inline stack locations for loop vars FAIL
  torvalds#111/p inline bpf_loop call in a big program FAIL
  Summary: 768 PASSED, 15 SKIPPED, 6 FAILED

The test log shows that callbacks are not allowed in non-JITed programs,
interpreter doesn't support them yet, thus these tests should be skipped
if jit is disabled, copy some check functions from the other places under
tools directory, and then handle this case in do_test_single().

With this patch:

  [root@linux bpf]# echo 0 > /proc/sys/net/core/bpf_jit_enable
  [root@linux bpf]# echo 0 > /proc/sys/kernel/unprivileged_bpf_disabled
  [root@linux bpf]# ./test_verifier | grep FAIL
  Summary: 768 PASSED, 21 SKIPPED, 0 FAILED

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this pull request Jan 16, 2024
@intel-lab-lkp
selftests/bpf: Skip callback tests if jit is disabled in test_verifier
49297c6 
If CONFIG_BPF_JIT_ALWAYS_ON is not set and bpf_jit_enable is 0, there
exist 6 failed tests.

  [root@linux bpf]# echo 0 > /proc/sys/net/core/bpf_jit_enable
  [root@linux bpf]# echo 0 > /proc/sys/kernel/unprivileged_bpf_disabled
  [root@linux bpf]# ./test_verifier | grep FAIL
  torvalds#106/p inline simple bpf_loop call FAIL
  torvalds#107/p don't inline bpf_loop call, flags non-zero FAIL
  torvalds#108/p don't inline bpf_loop call, callback non-constant FAIL
  torvalds#109/p bpf_loop_inline and a dead func FAIL
  torvalds#110/p bpf_loop_inline stack locations for loop vars FAIL
  torvalds#111/p inline bpf_loop call in a big program FAIL
  Summary: 768 PASSED, 15 SKIPPED, 6 FAILED

The test log shows that callbacks are not allowed in non-JITed programs,
interpreter doesn't support them yet, thus these tests should be skipped
if jit is disabled, copy some check functions from the other places under
tools directory, and then handle this case in do_test_single().

With this patch:

  [root@linux bpf]# echo 0 > /proc/sys/net/core/bpf_jit_enable
  [root@linux bpf]# echo 0 > /proc/sys/kernel/unprivileged_bpf_disabled
  [root@linux bpf]# ./test_verifier | grep FAIL
  Summary: 768 PASSED, 21 SKIPPED, 0 FAILED

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this pull request Jan 17, 2024
@intel-lab-lkp
selftests/bpf: Skip callback tests if jit is disabled in test_verifier
d784881 
If CONFIG_BPF_JIT_ALWAYS_ON is not set and bpf_jit_enable is 0, there
exist 6 failed tests.

  [root@linux bpf]# echo 0 > /proc/sys/net/core/bpf_jit_enable
  [root@linux bpf]# echo 0 > /proc/sys/kernel/unprivileged_bpf_disabled
  [root@linux bpf]# ./test_verifier | grep FAIL
  torvalds#106/p inline simple bpf_loop call FAIL
  torvalds#107/p don't inline bpf_loop call, flags non-zero FAIL
  torvalds#108/p don't inline bpf_loop call, callback non-constant FAIL
  torvalds#109/p bpf_loop_inline and a dead func FAIL
  torvalds#110/p bpf_loop_inline stack locations for loop vars FAIL
  torvalds#111/p inline bpf_loop call in a big program FAIL
  Summary: 768 PASSED, 15 SKIPPED, 6 FAILED

The test log shows that callbacks are not allowed in non-JITed programs,
interpreter doesn't support them yet, thus these tests should be skipped
if jit is disabled, just handle this case in do_test_single().

After including bpf/libbpf_internal.h, there exist some build errors:

  error: attempt to use poisoned "u32"
  error: attempt to use poisoned "u64"

replace u32 and u64 with __u32 and __u64 to fix them.

With this patch:

  [root@linux bpf]# echo 0 > /proc/sys/net/core/bpf_jit_enable
  [root@linux bpf]# echo 0 > /proc/sys/kernel/unprivileged_bpf_disabled
  [root@linux bpf]# ./test_verifier | grep FAIL
  Summary: 768 PASSED, 21 SKIPPED, 0 FAILED

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Acked-by: Hou Tao <houtao1@huawei.com>
logic10492 pushed a commit to logic10492/linux-amd-zen2 that referenced this pull request Jan 18, 2024
@htejun
Merge pull request torvalds#109 from sched-ext/dfl_slice
15f2f4f 
scx: Set default slice for default select_cpu dispatch
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this pull request Jan 22, 2024
@intel-lab-lkp
selftests/bpf: Skip callback tests if jit is disabled in test_verifier
e02f6bb 
If CONFIG_BPF_JIT_ALWAYS_ON is not set and bpf_jit_enable is 0, there
exist 6 failed tests.

  [root@linux bpf]# echo 0 > /proc/sys/net/core/bpf_jit_enable
  [root@linux bpf]# echo 0 > /proc/sys/kernel/unprivileged_bpf_disabled
  [root@linux bpf]# ./test_verifier | grep FAIL
  torvalds#106/p inline simple bpf_loop call FAIL
  torvalds#107/p don't inline bpf_loop call, flags non-zero FAIL
  torvalds#108/p don't inline bpf_loop call, callback non-constant FAIL
  torvalds#109/p bpf_loop_inline and a dead func FAIL
  torvalds#110/p bpf_loop_inline stack locations for loop vars FAIL
  torvalds#111/p inline bpf_loop call in a big program FAIL
  Summary: 768 PASSED, 15 SKIPPED, 6 FAILED

The test log shows that callbacks are not allowed in non-JITed programs,
interpreter doesn't support them yet, thus these tests should be skipped
if jit is disabled, just handle this case in do_test_single().

With this patch:

  [root@linux bpf]# echo 0 > /proc/sys/net/core/bpf_jit_enable
  [root@linux bpf]# echo 0 > /proc/sys/kernel/unprivileged_bpf_disabled
  [root@linux bpf]# ./test_verifier | grep FAIL
  Summary: 768 PASSED, 21 SKIPPED, 0 FAILED

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Acked-by: Hou Tao <houtao1@huawei.com>
Acked-by: Song Liu <song@kernel.org>
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this pull request Jan 23, 2024
@intel-lab-lkp
selftests/bpf: Skip callback tests if jit is disabled in test_verifier
dbf3f9a 
If CONFIG_BPF_JIT_ALWAYS_ON is not set and bpf_jit_enable is 0, there
exist 6 failed tests.

  [root@linux bpf]# echo 0 > /proc/sys/net/core/bpf_jit_enable
  [root@linux bpf]# echo 0 > /proc/sys/kernel/unprivileged_bpf_disabled
  [root@linux bpf]# ./test_verifier | grep FAIL
  torvalds#106/p inline simple bpf_loop call FAIL
  torvalds#107/p don't inline bpf_loop call, flags non-zero FAIL
  torvalds#108/p don't inline bpf_loop call, callback non-constant FAIL
  torvalds#109/p bpf_loop_inline and a dead func FAIL
  torvalds#110/p bpf_loop_inline stack locations for loop vars FAIL
  torvalds#111/p inline bpf_loop call in a big program FAIL
  Summary: 768 PASSED, 15 SKIPPED, 6 FAILED

The test log shows that callbacks are not allowed in non-JITed programs,
interpreter doesn't support them yet, thus these tests should be skipped
if jit is disabled.

Add an explicit flag F_NEEDS_JIT_ENABLED to those tests to mark that they
require JIT enabled in bpf_loop_inline.c, check the flag and jit_disabled
at the beginning of do_test_single() to handle this case.

With this patch:

  [root@linux bpf]# echo 0 > /proc/sys/net/core/bpf_jit_enable
  [root@linux bpf]# echo 0 > /proc/sys/kernel/unprivileged_bpf_disabled
  [root@linux bpf]# ./test_verifier | grep FAIL
  Summary: 768 PASSED, 21 SKIPPED, 0 FAILED

Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
alobakin pushed a commit to alobakin/linux that referenced this pull request Jan 24, 2024
@anakryiko
selftests/bpf: Skip callback tests if jit is disabled in test_verifier
0b50478 
If CONFIG_BPF_JIT_ALWAYS_ON is not set and bpf_jit_enable is 0, there
exist 6 failed tests.

  [root@linux bpf]# echo 0 > /proc/sys/net/core/bpf_jit_enable
  [root@linux bpf]# echo 0 > /proc/sys/kernel/unprivileged_bpf_disabled
  [root@linux bpf]# ./test_verifier | grep FAIL
  torvalds#106/p inline simple bpf_loop call FAIL
  torvalds#107/p don't inline bpf_loop call, flags non-zero FAIL
  torvalds#108/p don't inline bpf_loop call, callback non-constant FAIL
  torvalds#109/p bpf_loop_inline and a dead func FAIL
  torvalds#110/p bpf_loop_inline stack locations for loop vars FAIL
  torvalds#111/p inline bpf_loop call in a big program FAIL
  Summary: 768 PASSED, 15 SKIPPED, 6 FAILED

The test log shows that callbacks are not allowed in non-JITed programs,
interpreter doesn't support them yet, thus these tests should be skipped
if jit is disabled.

Add an explicit flag F_NEEDS_JIT_ENABLED to those tests to mark that they
require JIT enabled in bpf_loop_inline.c, check the flag and jit_disabled
at the beginning of do_test_single() to handle this case.

With this patch:

  [root@linux bpf]# echo 0 > /proc/sys/net/core/bpf_jit_enable
  [root@linux bpf]# echo 0 > /proc/sys/kernel/unprivileged_bpf_disabled
  [root@linux bpf]# ./test_verifier | grep FAIL
  Summary: 768 PASSED, 21 SKIPPED, 0 FAILED

Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240123090351.2207-3-yangtiezhu@loongson.cn
rodriguezst pushed a commit to rodriguezst/linux that referenced this pull request May 17, 2024
BACKPORT: FROMLIST: Bluetooth: adding configurable eir_max_name_len
e5590f8 
This change adds support for a configurable eir_max_name_len for
platforms which requires a larger than 48 bytes complete name in EIR.

From bluetoothctl:
[bluetooth]# system-alias
012345678901234567890123456789012345678901234567890123456789
Changing 012345678901234567890123456789012345678901234567890123456789
succeeded
[CHG] Controller DC:71:96:69:02:89 Alias:
012345678901234567890123456789012345678901234567890123456789

From btmon:
< HCI Command: Write Local Name (0x03|0x0013) plen 248     torvalds#109
[hci0] 88.567990
        Name:
012345678901234567890123456789012345678901234567890123456789
> HCI Event: Command Complete (0x0e) plen 4  torvalds#110 [hci0] 88.663854
      Write Local Name (0x03|0x0013) ncmd 1
        Status: Success (0x00)
@ MGMT Event: Local Name Changed (0x0008) plen 260               
{0x0004} [hci0] 88.663948
        Name:
012345678901234567890123456789012345678901234567890123456789
        Short name:
< HCI Command: Write Extended Inquiry Response (0x03|0x0052) plen 241
 torvalds#111 [hci0] 88.663977
        FEC: Not required (0x00)
        Name (complete):
012345678901234567890123456789012345678901234567890123456789
        TX power: 12 dBm
        Device ID: Bluetooth SIG assigned (0x0001)
          Vendor: Google (224)
          Product: 0xc405
          Version: 0.5.6 (0x0056)
        16-bit Service UUIDs (complete): 7 entries
          Generic Access Profile (0x1800)
          Generic Attribute Profile (0x1801)
          Device Information (0x180a)
          A/V Remote Control (0x110e)
          A/V Remote Control Target (0x110c)
          Handsfree Audio Gateway (0x111f)
          Audio Source (0x110a)
> HCI Event: Command Complete (0x0e) plen 4    torvalds#112 [hci0] 88.664874
      Write Extended Inquiry Response (0x03|0x0052) ncmd 1
        Status: Success (0x00)

    (am from https://patchwork.kernel.org/patch/11687367/)

Reviewed-by: Sonny Sasaka <sonnysasaka@chromium.org>
Reviewed-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
Signed-off-by: Alain Michaud <alainm@chromium.org>

Backport notes: HDEV_PARAM_U16 is changed from two parameters to one
parameter.

BUG=none
TEST=build

Signed-off-by: Zhengping Jiang <jiangzp@google.com>
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this pull request Aug 1, 2024
perf/x86: Fix smp_processor_id()-in-preemptible warnings
f73cefa 
The following bug was triggered on a system built with
CONFIG_DEBUG_PREEMPT=y:

 # echo p > /proc/sysrq-trigger

 BUG: using smp_processor_id() in preemptible [00000000] code: sh/117
 caller is perf_event_print_debug+0x1a/0x4c0
 CPU: 3 UID: 0 PID: 117 Comm: sh Not tainted 6.11.0-rc1 torvalds#109
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
 Call Trace:
  <TASK>
  dump_stack_lvl+0x4f/0x60
  check_preemption_disabled+0xc8/0xd0
  perf_event_print_debug+0x1a/0x4c0
  __handle_sysrq+0x140/0x180
  write_sysrq_trigger+0x61/0x70
  proc_reg_write+0x4e/0x70
  vfs_write+0xd0/0x430
  ? handle_mm_fault+0xc8/0x240
  ksys_write+0x9c/0xd0
  do_syscall_64+0x96/0x190
  entry_SYSCALL_64_after_hwframe+0x4b/0x53

This is because the commit d4b294b ("perf/x86: Hybrid PMU support
for counters") took smp_processor_id() outside the irq critical section.
If a preemption occurs in perf_event_print_debug() and the task is
migrated to another cpu, we may get incorrect pmu debug information.
Move smp_processor_id() back inside the irq critical section to fix this
issue.

Fixes: d4b294b ("perf/x86: Hybrid PMU support for counters")
Signed-off-by: Li Huafei <lihuafei1@huawei.com>
Reviewed-and-tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Link: https://lore.kernel.org/r/20240729220928.325449-1-lihuafei1@huawei.com
Kaz205 pushed a commit to Kaz205/linux that referenced this pull request Aug 14, 2024
@gregkh
perf/x86: Fix smp_processor_id()-in-preemptible warnings
856e1f7 
[ Upstream commit f73cefa ]

The following bug was triggered on a system built with
CONFIG_DEBUG_PREEMPT=y:

 # echo p > /proc/sysrq-trigger

 BUG: using smp_processor_id() in preemptible [00000000] code: sh/117
 caller is perf_event_print_debug+0x1a/0x4c0
 CPU: 3 UID: 0 PID: 117 Comm: sh Not tainted 6.11.0-rc1 torvalds#109
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
 Call Trace:
  <TASK>
  dump_stack_lvl+0x4f/0x60
  check_preemption_disabled+0xc8/0xd0
  perf_event_print_debug+0x1a/0x4c0
  __handle_sysrq+0x140/0x180
  write_sysrq_trigger+0x61/0x70
  proc_reg_write+0x4e/0x70
  vfs_write+0xd0/0x430
  ? handle_mm_fault+0xc8/0x240
  ksys_write+0x9c/0xd0
  do_syscall_64+0x96/0x190
  entry_SYSCALL_64_after_hwframe+0x4b/0x53

This is because the commit d4b294b ("perf/x86: Hybrid PMU support
for counters") took smp_processor_id() outside the irq critical section.
If a preemption occurs in perf_event_print_debug() and the task is
migrated to another cpu, we may get incorrect pmu debug information.
Move smp_processor_id() back inside the irq critical section to fix this
issue.

Fixes: d4b294b ("perf/x86: Hybrid PMU support for counters")
Signed-off-by: Li Huafei <lihuafei1@huawei.com>
Reviewed-and-tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Link: https://lore.kernel.org/r/20240729220928.325449-1-lihuafei1@huawei.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Kaz205 pushed a commit to Kaz205/linux that referenced this pull request Aug 14, 2024
perf/x86: Fix smp_processor_id()-in-preemptible warnings
2428231 
[ Upstream commit f73cefa ]

The following bug was triggered on a system built with
CONFIG_DEBUG_PREEMPT=y:

 # echo p > /proc/sysrq-trigger

 BUG: using smp_processor_id() in preemptible [00000000] code: sh/117
 caller is perf_event_print_debug+0x1a/0x4c0
 CPU: 3 UID: 0 PID: 117 Comm: sh Not tainted 6.11.0-rc1 torvalds#109
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
 Call Trace:
  <TASK>
  dump_stack_lvl+0x4f/0x60
  check_preemption_disabled+0xc8/0xd0
  perf_event_print_debug+0x1a/0x4c0
  __handle_sysrq+0x140/0x180
  write_sysrq_trigger+0x61/0x70
  proc_reg_write+0x4e/0x70
  vfs_write+0xd0/0x430
  ? handle_mm_fault+0xc8/0x240
  ksys_write+0x9c/0xd0
  do_syscall_64+0x96/0x190
  entry_SYSCALL_64_after_hwframe+0x4b/0x53

This is because the commit d4b294b ("perf/x86: Hybrid PMU support
for counters") took smp_processor_id() outside the irq critical section.
If a preemption occurs in perf_event_print_debug() and the task is
migrated to another cpu, we may get incorrect pmu debug information.
Move smp_processor_id() back inside the irq critical section to fix this
issue.

Fixes: d4b294b ("perf/x86: Hybrid PMU support for counters")
Signed-off-by: Li Huafei <lihuafei1@huawei.com>
Reviewed-and-tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Link: https://lore.kernel.org/r/20240729220928.325449-1-lihuafei1@huawei.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
intersectRaven pushed a commit to intersectRaven/linux that referenced this pull request Aug 14, 2024
@gregkh
perf/x86: Fix smp_processor_id()-in-preemptible warnings
0c7c3dc 
[ Upstream commit f73cefa ]

The following bug was triggered on a system built with
CONFIG_DEBUG_PREEMPT=y:

 # echo p > /proc/sysrq-trigger

 BUG: using smp_processor_id() in preemptible [00000000] code: sh/117
 caller is perf_event_print_debug+0x1a/0x4c0
 CPU: 3 UID: 0 PID: 117 Comm: sh Not tainted 6.11.0-rc1 torvalds#109
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
 Call Trace:
  <TASK>
  dump_stack_lvl+0x4f/0x60
  check_preemption_disabled+0xc8/0xd0
  perf_event_print_debug+0x1a/0x4c0
  __handle_sysrq+0x140/0x180
  write_sysrq_trigger+0x61/0x70
  proc_reg_write+0x4e/0x70
  vfs_write+0xd0/0x430
  ? handle_mm_fault+0xc8/0x240
  ksys_write+0x9c/0xd0
  do_syscall_64+0x96/0x190
  entry_SYSCALL_64_after_hwframe+0x4b/0x53

This is because the commit d4b294b ("perf/x86: Hybrid PMU support
for counters") took smp_processor_id() outside the irq critical section.
If a preemption occurs in perf_event_print_debug() and the task is
migrated to another cpu, we may get incorrect pmu debug information.
Move smp_processor_id() back inside the irq critical section to fix this
issue.

Fixes: d4b294b ("perf/x86: Hybrid PMU support for counters")
Signed-off-by: Li Huafei <lihuafei1@huawei.com>
Reviewed-and-tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Link: https://lore.kernel.org/r/20240729220928.325449-1-lihuafei1@huawei.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this pull request Aug 21, 2024
@jc2870 @intel-lab-lkp
btrfs: fix the race between umount and btrfs-cleaner
5504de9 
There is a race condition generic_shutdown_super() and
__btrfs_run_defrag_inode().
Consider the following scenario:

umount thread:             btrfs-cleaner thread:
			     btrfs_run_delayed_iputs()
			       ->run_delayed_iput_locked()
				->iput(inode)
				  // Here the inode (ie ino 261) will be cleared and freed
btrfs_kill_super()
  ->generic_shutdown_super()
    			     btrfs_run_defrag_inodes()
			       ->__btrfs_run_defrag_inode()
				->btrfs_iget(ino)
				// The inode 261 was recreated with i_count=1
				// and added to the sb list
    ->evict_inodes(sb)          // After some work
    // inode 261 was added      ->iput(inode)
    // to the dispose list        ->iput_funal()
      ->evict(inode)                ->evict(inode)

Now, we have two threads simultaneously evicting
the same inode, which led to a bug.

The above behavior can be confirmed by the log I added for debugging
and the log printed when BUG was triggered.
Due to space limitations, I cannot paste the full diff and here is a
brief describtion.

First, within __btrfs_run_defrag_inode(), set inode->i_state |= (1<<19)
just before calling iput().
Within the dispose_list(), check the flag, if the flag was set, then
pr_info("bug! double evict! crash will happen! state is 0x%lx\n", inode->i_state);

Here is the printed log when the BUG was triggered:
[  190.686726][ T2336] bug! double evict! crash will happen! state is 0x80020
[  190.687647][ T2336] ------------[ cut here ]------------
[  190.688294][ T2336] kernel BUG at fs/inode.c:626!
[  190.688939][ T2336] Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI
[  190.689792][ T2336] CPU: 1 PID: 2336 Comm: a.out Not tainted 6.10.0-rc2-00223-g0c529ab65ef8-dirty torvalds#109
[  190.690894][ T2336] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
[  190.692111][ T2336] RIP: 0010:clear_inode+0x15b/0x190
// some logs...
[  190.704501][ T2336]  btrfs_evict_inode+0x529/0xe80
[  190.706966][ T2336]  evict+0x2ed/0x6c0
[  190.707209][ T2336]  dispose_list+0x62/0x260
[  190.707490][ T2336]  evict_inodes+0x34e/0x450

To prevent this behavior, we need to set BTRFS_FS_CLOSING_START
before kill_anon_super() to ensure that
btrfs_run_defrag_inodes() doesn't continue working after unmount.

Reported-and-tested-by: syzbot+67ba3c42bcbb4665d3ad@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=67ba3c42bcbb4665d3ad
CC: stable@vger.kernel.org
Fixes: c146afa ("Btrfs: mount ro and remount support")
Signed-off-by: Julian Sun <sunjunchao2870@gmail.com>
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2 participants
@rosellef @kvaneesh