leds: Fix support for low-active PWM LED #10
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linux4kix
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Sep 1, 2015
leds: Fix support for low-active PWM LED
linux4kix
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Sep 5, 2015
commit ecf5fc6 upstream. Nikolay has reported a hang when a memcg reclaim got stuck with the following backtrace: PID: 18308 TASK: ffff883d7c9b0a30 CPU: 1 COMMAND: "rsync" #0 __schedule at ffffffff815ab152 #1 schedule at ffffffff815ab76e #2 schedule_timeout at ffffffff815ae5e5 #3 io_schedule_timeout at ffffffff815aad6a #4 bit_wait_io at ffffffff815abfc6 #5 __wait_on_bit at ffffffff815abda5 #6 wait_on_page_bit at ffffffff8111fd4f #7 shrink_page_list at ffffffff81135445 #8 shrink_inactive_list at ffffffff81135845 #9 shrink_lruvec at ffffffff81135ead #10 shrink_zone at ffffffff811360c3 #11 shrink_zones at ffffffff81136eff #12 do_try_to_free_pages at ffffffff8113712f #13 try_to_free_mem_cgroup_pages at ffffffff811372be #14 try_charge at ffffffff81189423 #15 mem_cgroup_try_charge at ffffffff8118c6f5 #16 __add_to_page_cache_locked at ffffffff8112137d #17 add_to_page_cache_lru at ffffffff81121618 #18 pagecache_get_page at ffffffff8112170b #19 grow_dev_page at ffffffff811c8297 #20 __getblk_slow at ffffffff811c91d6 #21 __getblk_gfp at ffffffff811c92c1 #22 ext4_ext_grow_indepth at ffffffff8124565c #23 ext4_ext_create_new_leaf at ffffffff81246ca8 #24 ext4_ext_insert_extent at ffffffff81246f09 #25 ext4_ext_map_blocks at ffffffff8124a848 #26 ext4_map_blocks at ffffffff8121a5b7 #27 mpage_map_one_extent at ffffffff8121b1fa #28 mpage_map_and_submit_extent at ffffffff8121f07b #29 ext4_writepages at ffffffff8121f6d5 #30 do_writepages at ffffffff8112c490 #31 __filemap_fdatawrite_range at ffffffff81120199 #32 filemap_flush at ffffffff8112041c #33 ext4_alloc_da_blocks at ffffffff81219da1 #34 ext4_rename at ffffffff81229b91 #35 ext4_rename2 at ffffffff81229e32 #36 vfs_rename at ffffffff811a08a5 #37 SYSC_renameat2 at ffffffff811a3ffc #38 sys_renameat2 at ffffffff811a408e #39 sys_rename at ffffffff8119e51e #40 system_call_fastpath at ffffffff815afa89 Dave Chinner has properly pointed out that this is a deadlock in the reclaim code because ext4 doesn't submit pages which are marked by PG_writeback right away. The heuristic was introduced by commit e62e384 ("memcg: prevent OOM with too many dirty pages") and it was applied only when may_enter_fs was specified. The code has been changed by c3b94f4 ("memcg: further prevent OOM with too many dirty pages") which has removed the __GFP_FS restriction with a reasoning that we do not get into the fs code. But this is not sufficient apparently because the fs doesn't necessarily submit pages marked PG_writeback for IO right away. ext4_bio_write_page calls io_submit_add_bh but that doesn't necessarily submit the bio. Instead it tries to map more pages into the bio and mpage_map_one_extent might trigger memcg charge which might end up waiting on a page which is marked PG_writeback but hasn't been submitted yet so we would end up waiting for something that never finishes. Fix this issue by replacing __GFP_IO by may_enter_fs check (for case 2) before we go to wait on the writeback. The page fault path, which is the only path that triggers memcg oom killer since 3.12, shouldn't require GFP_NOFS and so we shouldn't reintroduce the premature OOM killer issue which was originally addressed by the heuristic. As per David Chinner the xfs is doing similar thing since 2.6.15 already so ext4 is not the only affected filesystem. Moreover he notes: : For example: IO completion might require unwritten extent conversion : which executes filesystem transactions and GFP_NOFS allocations. The : writeback flag on the pages can not be cleared until unwritten : extent conversion completes. Hence memory reclaim cannot wait on : page writeback to complete in GFP_NOFS context because it is not : safe to do so, memcg reclaim or otherwise. [tytso@mit.edu: corrected the control flow] Fixes: c3b94f4 ("memcg: further prevent OOM with too many dirty pages") Reported-by: Nikolay Borisov <kernel@kyup.com> Signed-off-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mk01
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Oct 9, 2015
commit ecf5fc6 upstream. Nikolay has reported a hang when a memcg reclaim got stuck with the following backtrace: PID: 18308 TASK: ffff883d7c9b0a30 CPU: 1 COMMAND: "rsync" #0 __schedule at ffffffff815ab152 SolidRun#1 schedule at ffffffff815ab76e SolidRun#2 schedule_timeout at ffffffff815ae5e5 SolidRun#3 io_schedule_timeout at ffffffff815aad6a SolidRun#4 bit_wait_io at ffffffff815abfc6 SolidRun#5 __wait_on_bit at ffffffff815abda5 SolidRun#6 wait_on_page_bit at ffffffff8111fd4f SolidRun#7 shrink_page_list at ffffffff81135445 SolidRun#8 shrink_inactive_list at ffffffff81135845 SolidRun#9 shrink_lruvec at ffffffff81135ead SolidRun#10 shrink_zone at ffffffff811360c3 SolidRun#11 shrink_zones at ffffffff81136eff SolidRun#12 do_try_to_free_pages at ffffffff8113712f SolidRun#13 try_to_free_mem_cgroup_pages at ffffffff811372be SolidRun#14 try_charge at ffffffff81189423 SolidRun#15 mem_cgroup_try_charge at ffffffff8118c6f5 SolidRun#16 __add_to_page_cache_locked at ffffffff8112137d SolidRun#17 add_to_page_cache_lru at ffffffff81121618 SolidRun#18 pagecache_get_page at ffffffff8112170b SolidRun#19 grow_dev_page at ffffffff811c8297 SolidRun#20 __getblk_slow at ffffffff811c91d6 SolidRun#21 __getblk_gfp at ffffffff811c92c1 SolidRun#22 ext4_ext_grow_indepth at ffffffff8124565c SolidRun#23 ext4_ext_create_new_leaf at ffffffff81246ca8 SolidRun#24 ext4_ext_insert_extent at ffffffff81246f09 SolidRun#25 ext4_ext_map_blocks at ffffffff8124a848 SolidRun#26 ext4_map_blocks at ffffffff8121a5b7 SolidRun#27 mpage_map_one_extent at ffffffff8121b1fa SolidRun#28 mpage_map_and_submit_extent at ffffffff8121f07b SolidRun#29 ext4_writepages at ffffffff8121f6d5 SolidRun#30 do_writepages at ffffffff8112c490 SolidRun#31 __filemap_fdatawrite_range at ffffffff81120199 SolidRun#32 filemap_flush at ffffffff8112041c SolidRun#33 ext4_alloc_da_blocks at ffffffff81219da1 SolidRun#34 ext4_rename at ffffffff81229b91 SolidRun#35 ext4_rename2 at ffffffff81229e32 SolidRun#36 vfs_rename at ffffffff811a08a5 SolidRun#37 SYSC_renameat2 at ffffffff811a3ffc SolidRun#38 sys_renameat2 at ffffffff811a408e SolidRun#39 sys_rename at ffffffff8119e51e SolidRun#40 system_call_fastpath at ffffffff815afa89 Dave Chinner has properly pointed out that this is a deadlock in the reclaim code because ext4 doesn't submit pages which are marked by PG_writeback right away. The heuristic was introduced by commit e62e384 ("memcg: prevent OOM with too many dirty pages") and it was applied only when may_enter_fs was specified. The code has been changed by c3b94f4 ("memcg: further prevent OOM with too many dirty pages") which has removed the __GFP_FS restriction with a reasoning that we do not get into the fs code. But this is not sufficient apparently because the fs doesn't necessarily submit pages marked PG_writeback for IO right away. ext4_bio_write_page calls io_submit_add_bh but that doesn't necessarily submit the bio. Instead it tries to map more pages into the bio and mpage_map_one_extent might trigger memcg charge which might end up waiting on a page which is marked PG_writeback but hasn't been submitted yet so we would end up waiting for something that never finishes. Fix this issue by replacing __GFP_IO by may_enter_fs check (for case 2) before we go to wait on the writeback. The page fault path, which is the only path that triggers memcg oom killer since 3.12, shouldn't require GFP_NOFS and so we shouldn't reintroduce the premature OOM killer issue which was originally addressed by the heuristic. As per David Chinner the xfs is doing similar thing since 2.6.15 already so ext4 is not the only affected filesystem. Moreover he notes: : For example: IO completion might require unwritten extent conversion : which executes filesystem transactions and GFP_NOFS allocations. The : writeback flag on the pages can not be cleared until unwritten : extent conversion completes. Hence memory reclaim cannot wait on : page writeback to complete in GFP_NOFS context because it is not : safe to do so, memcg reclaim or otherwise. Cc: stable@vger.kernel.org # 3.9+ [tytso@mit.edu: corrected the control flow] Fixes: c3b94f4 ("memcg: further prevent OOM with too many dirty pages") Reported-by: Nikolay Borisov <kernel@kyup.com> Signed-off-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mk01
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Mar 2, 2016
commit ec183d2 upstream. Fixes segmentation fault using, for instance: (gdb) run record -I -e intel_pt/tsc=1,noretcomp=1/u /bin/ls Starting program: /home/acme/bin/perf record -I -e intel_pt/tsc=1,noretcomp=1/u /bin/ls Missing separate debuginfos, use: dnf debuginfo-install glibc-2.22-7.fc23.x86_64 [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib64/libthread_db.so.1". Program received signal SIGSEGV, Segmentation fault. 0 x00000000004b9ea5 in tracepoint_error (e=0x0, err=13, sys=0x19b1370 "sched", name=0x19a5d00 "sched_switch") at util/parse-events.c:410 (gdb) bt #0 0x00000000004b9ea5 in tracepoint_error (e=0x0, err=13, sys=0x19b1370 "sched", name=0x19a5d00 "sched_switch") at util/parse-events.c:410 SolidRun#1 0x00000000004b9fc5 in add_tracepoint (list=0x19a5d20, idx=0x7fffffffb8c0, sys_name=0x19b1370 "sched", evt_name=0x19a5d00 "sched_switch", err=0x0, head_config=0x0) at util/parse-events.c:433 SolidRun#2 0x00000000004ba334 in add_tracepoint_event (list=0x19a5d20, idx=0x7fffffffb8c0, sys_name=0x19b1370 "sched", evt_name=0x19a5d00 "sched_switch", err=0x0, head_config=0x0) at util/parse-events.c:498 SolidRun#3 0x00000000004bb699 in parse_events_add_tracepoint (list=0x19a5d20, idx=0x7fffffffb8c0, sys=0x19b1370 "sched", event=0x19a5d00 "sched_switch", err=0x0, head_config=0x0) at util/parse-events.c:936 SolidRun#4 0x00000000004f6eda in parse_events_parse (_data=0x7fffffffb8b0, scanner=0x19a49d0) at util/parse-events.y:391 SolidRun#5 0x00000000004bc8e5 in parse_events__scanner (str=0x663ff2 "sched:sched_switch", data=0x7fffffffb8b0, start_token=258) at util/parse-events.c:1361 SolidRun#6 0x00000000004bca57 in parse_events (evlist=0x19a5220, str=0x663ff2 "sched:sched_switch", err=0x0) at util/parse-events.c:1401 SolidRun#7 0x0000000000518d5f in perf_evlist__can_select_event (evlist=0x19a3b90, str=0x663ff2 "sched:sched_switch") at util/record.c:253 SolidRun#8 0x0000000000553c42 in intel_pt_track_switches (evlist=0x19a3b90) at arch/x86/util/intel-pt.c:364 SolidRun#9 0x00000000005549d1 in intel_pt_recording_options (itr=0x19a2c40, evlist=0x19a3b90, opts=0x8edf68 <record+232>) at arch/x86/util/intel-pt.c:664 SolidRun#10 0x000000000051e076 in auxtrace_record__options (itr=0x19a2c40, evlist=0x19a3b90, opts=0x8edf68 <record+232>) at util/auxtrace.c:539 SolidRun#11 0x0000000000433368 in cmd_record (argc=1, argv=0x7fffffffde60, prefix=0x0) at builtin-record.c:1264 SolidRun#12 0x000000000049bec2 in run_builtin (p=0x8fa2a8 <commands+168>, argc=5, argv=0x7fffffffde60) at perf.c:390 SolidRun#13 0x000000000049c12a in handle_internal_command (argc=5, argv=0x7fffffffde60) at perf.c:451 SolidRun#14 0x000000000049c278 in run_argv (argcp=0x7fffffffdcbc, argv=0x7fffffffdcb0) at perf.c:495 SolidRun#15 0x000000000049c60a in main (argc=5, argv=0x7fffffffde60) at perf.c:618 (gdb) Intel PT attempts to find the sched:sched_switch tracepoint but that seg faults if tracefs is not readable, because the error reporting structure is null, as errors are not reported when automatically adding tracepoints. Fix by checking before using. Committer note: This doesn't take place in a kernel that supports perf_event_attr.context_switch, that is the default way that will be used for tracking context switches, only in older kernels, like 4.2, in a machine with Intel PT (e.g. Broadwell) for non-priviledged users. Further info from a similar patch by Wang: The error is in tracepoint_error: it assumes the 'e' parameter is valid. However, there are many situation a parse_event() can be called without parse_events_error. See result of $ grep 'parse_events(.*NULL)' ./tools/perf/ -r' Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Tong Zhang <ztong@vt.edu> Cc: Wang Nan <wangnan0@huawei.com> Fixes: 1965817 ("perf tools: Enhance parsing events tracepoint error output") Link: http://lkml.kernel.org/r/1453809921-24596-2-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mk01
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Apr 26, 2016
…antiated commit 3c2e226 upstream. arm:pxa_defconfig can result in the following crash if the max1111 driver is not instantiated. Unhandled fault: page domain fault (0x01b) at 0x00000000 pgd = c0004000 [00000000] *pgd=00000000 Internal error: : 1b [SolidRun#1] PREEMPT ARM Modules linked in: CPU: 0 PID: 300 Comm: kworker/0:1 Not tainted 4.5.0-01301-g1701f680407c SolidRun#10 Hardware name: SHARP Akita Workqueue: events sharpsl_charge_toggle task: c390a000 ti: c391e000 task.ti: c391e000 PC is at max1111_read_channel+0x20/0x30 LR is at sharpsl_pm_pxa_read_max1111+0x2c/0x3c pc : [<c03aaab0>] lr : [<c0024b50>] psr: 20000013 ... [<c03aaab0>] (max1111_read_channel) from [<c0024b50>] (sharpsl_pm_pxa_read_max1111+0x2c/0x3c) [<c0024b50>] (sharpsl_pm_pxa_read_max1111) from [<c00262e0>] (spitzpm_read_devdata+0x5c/0xc4) [<c00262e0>] (spitzpm_read_devdata) from [<c0024094>] (sharpsl_check_battery_temp+0x78/0x110) [<c0024094>] (sharpsl_check_battery_temp) from [<c0024f9c>] (sharpsl_charge_toggle+0x48/0x110) [<c0024f9c>] (sharpsl_charge_toggle) from [<c004429c>] (process_one_work+0x14c/0x48c) [<c004429c>] (process_one_work) from [<c0044618>] (worker_thread+0x3c/0x5d4) [<c0044618>] (worker_thread) from [<c004a238>] (kthread+0xd0/0xec) [<c004a238>] (kthread) from [<c000a670>] (ret_from_fork+0x14/0x24) This can occur because the SPI controller driver (SPI_PXA2XX) is built as module and thus not necessarily loaded. While building SPI_PXA2XX into the kernel would make the problem disappear, it appears prudent to ensure that the driver is instantiated before accessing its data structures. Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
linux4kix
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Oct 20, 2016
…antiated commit 3c2e226 upstream. arm:pxa_defconfig can result in the following crash if the max1111 driver is not instantiated. Unhandled fault: page domain fault (0x01b) at 0x00000000 pgd = c0004000 [00000000] *pgd=00000000 Internal error: : 1b [#1] PREEMPT ARM Modules linked in: CPU: 0 PID: 300 Comm: kworker/0:1 Not tainted 4.5.0-01301-g1701f680407c #10 Hardware name: SHARP Akita Workqueue: events sharpsl_charge_toggle task: c390a000 ti: c391e000 task.ti: c391e000 PC is at max1111_read_channel+0x20/0x30 LR is at sharpsl_pm_pxa_read_max1111+0x2c/0x3c pc : [<c03aaab0>] lr : [<c0024b50>] psr: 20000013 ... [<c03aaab0>] (max1111_read_channel) from [<c0024b50>] (sharpsl_pm_pxa_read_max1111+0x2c/0x3c) [<c0024b50>] (sharpsl_pm_pxa_read_max1111) from [<c00262e0>] (spitzpm_read_devdata+0x5c/0xc4) [<c00262e0>] (spitzpm_read_devdata) from [<c0024094>] (sharpsl_check_battery_temp+0x78/0x110) [<c0024094>] (sharpsl_check_battery_temp) from [<c0024f9c>] (sharpsl_charge_toggle+0x48/0x110) [<c0024f9c>] (sharpsl_charge_toggle) from [<c004429c>] (process_one_work+0x14c/0x48c) [<c004429c>] (process_one_work) from [<c0044618>] (worker_thread+0x3c/0x5d4) [<c0044618>] (worker_thread) from [<c004a238>] (kthread+0xd0/0xec) [<c004a238>] (kthread) from [<c000a670>] (ret_from_fork+0x14/0x24) This can occur because the SPI controller driver (SPI_PXA2XX) is built as module and thus not necessarily loaded. While building SPI_PXA2XX into the kernel would make the problem disappear, it appears prudent to ensure that the driver is instantiated before accessing its data structures. Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
jnettlet
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Sep 3, 2018
[ Upstream commit 2c0aa08 ] Scenario: 1. Port down and do fail over 2. Ap do rds_bind syscall PID: 47039 TASK: ffff89887e2fe640 CPU: 47 COMMAND: "kworker/u:6" #0 [ffff898e35f159f0] machine_kexec at ffffffff8103abf9 #1 [ffff898e35f15a60] crash_kexec at ffffffff810b96e3 #2 [ffff898e35f15b30] oops_end at ffffffff8150f518 #3 [ffff898e35f15b60] no_context at ffffffff8104854c #4 [ffff898e35f15ba0] __bad_area_nosemaphore at ffffffff81048675 #5 [ffff898e35f15bf0] bad_area_nosemaphore at ffffffff810487d3 #6 [ffff898e35f15c00] do_page_fault at ffffffff815120b8 #7 [ffff898e35f15d10] page_fault at ffffffff8150ea95 [exception RIP: unknown or invalid address] RIP: 0000000000000000 RSP: ffff898e35f15dc8 RFLAGS: 00010282 RAX: 00000000fffffffe RBX: ffff889b77f6fc00 RCX:ffffffff81c99d88 RDX: 0000000000000000 RSI: ffff896019ee08e8 RDI:ffff889b77f6fc00 RBP: ffff898e35f15df0 R8: ffff896019ee08c8 R9:0000000000000000 R10: 0000000000000400 R11: 0000000000000000 R12:ffff896019ee08c0 R13: ffff889b77f6fe68 R14: ffffffff81c99d80 R15: ffffffffa022a1e0 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 #8 [ffff898e35f15dc8] cma_ndev_work_handler at ffffffffa022a228 [rdma_cm] #9 [ffff898e35f15df8] process_one_work at ffffffff8108a7c6 #10 [ffff898e35f15e58] worker_thread at ffffffff8108bda0 #11 [ffff898e35f15ee8] kthread at ffffffff81090fe6 PID: 45659 TASK: ffff880d313d2500 CPU: 31 COMMAND: "oracle_45659_ap" #0 [ffff881024ccfc98] __schedule at ffffffff8150bac4 #1 [ffff881024ccfd40] schedule at ffffffff8150c2cf #2 [ffff881024ccfd50] __mutex_lock_slowpath at ffffffff8150cee7 #3 [ffff881024ccfdc0] mutex_lock at ffffffff8150cdeb #4 [ffff881024ccfde0] rdma_destroy_id at ffffffffa022a027 [rdma_cm] #5 [ffff881024ccfe10] rds_ib_laddr_check at ffffffffa0357857 [rds_rdma] #6 [ffff881024ccfe50] rds_trans_get_preferred at ffffffffa0324c2a [rds] #7 [ffff881024ccfe80] rds_bind at ffffffffa031d690 [rds] #8 [ffff881024ccfeb0] sys_bind at ffffffff8142a670 PID: 45659 PID: 47039 rds_ib_laddr_check /* create id_priv with a null event_handler */ rdma_create_id rdma_bind_addr cma_acquire_dev /* add id_priv to cma_dev->id_list */ cma_attach_to_dev cma_ndev_work_handler /* event_hanlder is null */ id_priv->id.event_handler Signed-off-by: Guanglei Li <guanglei.li@oracle.com> Signed-off-by: Honglei Wang <honglei.wang@oracle.com> Reviewed-by: Junxiao Bi <junxiao.bi@oracle.com> Reviewed-by: Yanjun Zhu <yanjun.zhu@oracle.com> Reviewed-by: Leon Romanovsky <leonro@mellanox.com> Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Acked-by: Doug Ledford <dledford@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
jnettlet
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Sep 3, 2018
[ Upstream commit fca3234 ] Executing command 'perf stat -T -- ls' dumps core on x86 and s390. Here is the call back chain (done on x86): # gdb ./perf .... (gdb) r stat -T -- ls ... Program received signal SIGSEGV, Segmentation fault. 0x00007ffff56d1963 in vasprintf () from /lib64/libc.so.6 (gdb) where #0 0x00007ffff56d1963 in vasprintf () from /lib64/libc.so.6 #1 0x00007ffff56ae484 in asprintf () from /lib64/libc.so.6 #2 0x00000000004f1982 in __parse_events_add_pmu (parse_state=0x7fffffffd580, list=0xbfb970, name=0xbf3ef0 "cpu", head_config=0xbfb930, auto_merge_stats=false) at util/parse-events.c:1233 #3 0x00000000004f1c8e in parse_events_add_pmu (parse_state=0x7fffffffd580, list=0xbfb970, name=0xbf3ef0 "cpu", head_config=0xbfb930) at util/parse-events.c:1288 #4 0x0000000000537ce3 in parse_events_parse (_parse_state=0x7fffffffd580, scanner=0xbf4210) at util/parse-events.y:234 #5 0x00000000004f2c7a in parse_events__scanner (str=0x6b66c0 "task-clock,{instructions,cycles,cpu/cycles-t/,cpu/tx-start/}", parse_state=0x7fffffffd580, start_token=258) at util/parse-events.c:1673 #6 0x00000000004f2e23 in parse_events (evlist=0xbe9990, str=0x6b66c0 "task-clock,{instructions,cycles,cpu/cycles-t/,cpu/tx-start/}", err=0x0) at util/parse-events.c:1713 #7 0x000000000044e137 in add_default_attributes () at builtin-stat.c:2281 #8 0x000000000044f7b5 in cmd_stat (argc=1, argv=0x7fffffffe3b0) at builtin-stat.c:2828 #9 0x00000000004c8b0f in run_builtin (p=0xab01a0 <commands+288>, argc=4, argv=0x7fffffffe3b0) at perf.c:297 #10 0x00000000004c8d7c in handle_internal_command (argc=4, argv=0x7fffffffe3b0) at perf.c:349 #11 0x00000000004c8ece in run_argv (argcp=0x7fffffffe20c, argv=0x7fffffffe200) at perf.c:393 #12 0x00000000004c929c in main (argc=4, argv=0x7fffffffe3b0) at perf.c:537 (gdb) It turns out that a NULL pointer is referenced. Here are the function calls: ... cmd_stat() +---> add_default_attributes() +---> parse_events(evsel_list, transaction_attrs, NULL); 3rd parameter set to NULL Function parse_events(xx, xx, struct parse_events_error *err) dives into a bison generated scanner and creates parser state information for it first: struct parse_events_state parse_state = { .list = LIST_HEAD_INIT(parse_state.list), .idx = evlist->nr_entries, .error = err, <--- NULL POINTER !!! .evlist = evlist, }; Now various functions inside the bison scanner are called to end up in __parse_events_add_pmu(struct parse_events_state *parse_state, ..) with first parameter being a pointer to above structure definition. Now the PMU event name is not found (because being executed in a VM) and this function tries to create an error message with asprintf(&parse_state->error.str, ....) which references a NULL pointer and dumps core. Fix this by providing a pointer to the necessary error information instead of NULL. Technically only the else part is needed to avoid the core dump, just lets be safe... Signed-off-by: Thomas Richter <tmricht@linux.vnet.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Link: http://lkml.kernel.org/r/20180308145735.64717-1-tmricht@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 2bbea6e ] when mounting an ISO filesystem sometimes (very rarely) the system hangs because of a race condition between two tasks. PID: 6766 TASK: ffff88007b2a6dd0 CPU: 0 COMMAND: "mount" #0 [ffff880078447ae0] __schedule at ffffffff8168d605 #1 [ffff880078447b48] schedule_preempt_disabled at ffffffff8168ed49 #2 [ffff880078447b58] __mutex_lock_slowpath at ffffffff8168c995 #3 [ffff880078447bb8] mutex_lock at ffffffff8168bdef #4 [ffff880078447bd0] sr_block_ioctl at ffffffffa00b6818 [sr_mod] #5 [ffff880078447c10] blkdev_ioctl at ffffffff812fea50 #6 [ffff880078447c70] ioctl_by_bdev at ffffffff8123a8b3 #7 [ffff880078447c90] isofs_fill_super at ffffffffa04fb1e1 [isofs] #8 [ffff880078447da8] mount_bdev at ffffffff81202570 #9 [ffff880078447e18] isofs_mount at ffffffffa04f9828 [isofs] #10 [ffff880078447e28] mount_fs at ffffffff81202d09 #11 [ffff880078447e70] vfs_kern_mount at ffffffff8121ea8f #12 [ffff880078447ea8] do_mount at ffffffff81220fee #13 [ffff880078447f28] sys_mount at ffffffff812218d6 #14 [ffff880078447f80] system_call_fastpath at ffffffff81698c49 RIP: 00007fd9ea914e9a RSP: 00007ffd5d9bf648 RFLAGS: 00010246 RAX: 00000000000000a5 RBX: ffffffff81698c49 RCX: 0000000000000010 RDX: 00007fd9ec2bc210 RSI: 00007fd9ec2bc290 RDI: 00007fd9ec2bcf30 RBP: 0000000000000000 R8: 0000000000000000 R9: 0000000000000010 R10: 00000000c0ed0001 R11: 0000000000000206 R12: 00007fd9ec2bc040 R13: 00007fd9eb6b2380 R14: 00007fd9ec2bc210 R15: 00007fd9ec2bcf30 ORIG_RAX: 00000000000000a5 CS: 0033 SS: 002b This task was trying to mount the cdrom. It allocated and configured a super_block struct and owned the write-lock for the super_block->s_umount rwsem. While exclusively owning the s_umount lock, it called sr_block_ioctl and waited to acquire the global sr_mutex lock. PID: 6785 TASK: ffff880078720fb0 CPU: 0 COMMAND: "systemd-udevd" #0 [ffff880078417898] __schedule at ffffffff8168d605 #1 [ffff880078417900] schedule at ffffffff8168dc59 #2 [ffff880078417910] rwsem_down_read_failed at ffffffff8168f605 #3 [ffff880078417980] call_rwsem_down_read_failed at ffffffff81328838 #4 [ffff8800784179d0] down_read at ffffffff8168cde0 #5 [ffff8800784179e8] get_super at ffffffff81201cc7 #6 [ffff880078417a10] __invalidate_device at ffffffff8123a8de #7 [ffff880078417a40] flush_disk at ffffffff8123a94b #8 [ffff880078417a88] check_disk_change at ffffffff8123ab50 #9 [ffff880078417ab0] cdrom_open at ffffffffa00a29e1 [cdrom] #10 [ffff880078417b68] sr_block_open at ffffffffa00b6f9b [sr_mod] #11 [ffff880078417b98] __blkdev_get at ffffffff8123ba86 #12 [ffff880078417bf0] blkdev_get at ffffffff8123bd65 #13 [ffff880078417c78] blkdev_open at ffffffff8123bf9b #14 [ffff880078417c90] do_dentry_open at ffffffff811fc7f7 #15 [ffff880078417cd8] vfs_open at ffffffff811fc9cf #16 [ffff880078417d00] do_last at ffffffff8120d53d #17 [ffff880078417db0] path_openat at ffffffff8120e6b2 #18 [ffff880078417e48] do_filp_open at ffffffff8121082b #19 [ffff880078417f18] do_sys_open at ffffffff811fdd33 #20 [ffff880078417f70] sys_open at ffffffff811fde4e #21 [ffff880078417f80] system_call_fastpath at ffffffff81698c49 RIP: 00007f29438b0c20 RSP: 00007ffc76624b78 RFLAGS: 00010246 RAX: 0000000000000002 RBX: ffffffff81698c49 RCX: 0000000000000000 RDX: 00007f2944a5fa70 RSI: 00000000000a0800 RDI: 00007f2944a5fa70 RBP: 00007f2944a5f540 R8: 0000000000000000 R9: 0000000000000020 R10: 00007f2943614c40 R11: 0000000000000246 R12: ffffffff811fde4e R13: ffff880078417f78 R14: 000000000000000c R15: 00007f2944a4b010 ORIG_RAX: 0000000000000002 CS: 0033 SS: 002b This task tried to open the cdrom device, the sr_block_open function acquired the global sr_mutex lock. The call to check_disk_change() then saw an event flag indicating a possible media change and tried to flush any cached data for the device. As part of the flush, it tried to acquire the super_block->s_umount lock associated with the cdrom device. This was the same super_block as created and locked by the previous task. The first task acquires the s_umount lock and then the sr_mutex_lock; the second task acquires the sr_mutex_lock and then the s_umount lock. This patch fixes the issue by moving check_disk_change() out of cdrom_open() and let the caller take care of it. Signed-off-by: Maurizio Lombardi <mlombard@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Support for the 'low-active ' property was only partially implemented.