From a87765edd6440ec216f89a82d9084e1bec6b74ae Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 21 Jun 2024 16:08:28 +0200 Subject: [PATCH] selftests/bpf: Add more ring buffer test coverage Add test coverage for reservations beyond the ring buffer size in order to validate that bpf_ringbuf_reserve() rejects the request with NULL, all other ring buffer tests keep passing as well: # ./vmtest.sh -- ./test_progs -t ringbuf [...] ./test_progs -t ringbuf [ 1.165434] bpf_testmod: loading out-of-tree module taints kernel. [ 1.165825] bpf_testmod: module verification failed: signature and/or required key missing - tainting kernel [ 1.284001] tsc: Refined TSC clocksource calibration: 3407.982 MHz [ 1.286871] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x311fc34e357, max_idle_ns: 440795379773 ns [ 1.289555] clocksource: Switched to clocksource tsc #274/1 ringbuf/ringbuf:OK #274/2 ringbuf/ringbuf_n:OK #274/3 ringbuf/ringbuf_map_key:OK #274/4 ringbuf/ringbuf_write:OK #274 ringbuf:OK #275 ringbuf_multi:OK [...] Signed-off-by: Daniel Borkmann --- tools/testing/selftests/bpf/Makefile | 2 +- .../selftests/bpf/prog_tests/ringbuf.c | 46 +++++++++++++++++++ .../selftests/bpf/progs/test_ringbuf_write.c | 42 +++++++++++++++++ 3 files changed, 89 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/bpf/progs/test_ringbuf_write.c diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index e0b3887b3d2df1..dd49c1d23a604c 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -457,7 +457,7 @@ LINKED_SKELS := test_static_linked.skel.h linked_funcs.skel.h \ LSKELS := fentry_test.c fexit_test.c fexit_sleep.c atomics.c \ trace_printk.c trace_vprintk.c map_ptr_kern.c \ core_kern.c core_kern_overflow.c test_ringbuf.c \ - test_ringbuf_n.c test_ringbuf_map_key.c + test_ringbuf_n.c test_ringbuf_map_key.c test_ringbuf_write.c # Generate both light skeleton and libbpf skeleton for these LSKELS_EXTRA := test_ksyms_module.c test_ksyms_weak.c kfunc_call_test.c \ diff --git a/tools/testing/selftests/bpf/prog_tests/ringbuf.c b/tools/testing/selftests/bpf/prog_tests/ringbuf.c index 4c6f42dae4096c..40fd6021535349 100644 --- a/tools/testing/selftests/bpf/prog_tests/ringbuf.c +++ b/tools/testing/selftests/bpf/prog_tests/ringbuf.c @@ -12,9 +12,11 @@ #include #include #include + #include "test_ringbuf.lskel.h" #include "test_ringbuf_n.lskel.h" #include "test_ringbuf_map_key.lskel.h" +#include "test_ringbuf_write.lskel.h" #define EDONE 7777 @@ -84,6 +86,48 @@ static void *poll_thread(void *input) return (void *)(long)ring_buffer__poll(ringbuf, timeout); } +static void ringbuf_write_subtest(void) +{ + struct test_ringbuf_write_lskel *skel; + int page_size = getpagesize(); + size_t *mmap_ptr; + int err, rb_fd; + + skel = test_ringbuf_write_lskel__open(); + if (!ASSERT_OK_PTR(skel, "skel_load")) + return; + + skel->maps.ringbuf.max_entries = 0x4000; + + err = test_ringbuf_write_lskel__load(skel); + if (!ASSERT_OK(err, "ringbuf_write")) + goto cleanup; + + rb_fd = skel->maps.ringbuf.map_fd; + + mmap_ptr = mmap(NULL, page_size, PROT_READ | PROT_WRITE, MAP_SHARED, rb_fd, 0); + ASSERT_OK_PTR(mmap_ptr, "rw_cons_pos"); + *mmap_ptr = 0x3000; + ASSERT_OK(munmap(mmap_ptr, page_size), "unmap_rw"); + + skel->bss->pid = getpid(); + + ringbuf = ring_buffer__new(rb_fd, process_sample, NULL, NULL); + if (!ASSERT_OK_PTR(ringbuf, "ringbuf_create")) + goto cleanup; + + err = test_ringbuf_write_lskel__attach(skel); + if (!ASSERT_OK(err, "ringbuf_write")) + goto cleanup; + + trigger_samples(); + ASSERT_GE(skel->bss->discarded, 1, "discarded"); + ASSERT_EQ(skel->bss->passed, 0, "passed"); +cleanup: + ring_buffer__free(ringbuf); + test_ringbuf_write_lskel__destroy(skel); +} + static void ringbuf_subtest(void) { const size_t rec_sz = BPF_RINGBUF_HDR_SZ + sizeof(struct sample); @@ -451,4 +495,6 @@ void test_ringbuf(void) ringbuf_n_subtest(); if (test__start_subtest("ringbuf_map_key")) ringbuf_map_key_subtest(); + if (test__start_subtest("ringbuf_write")) + ringbuf_write_subtest(); } diff --git a/tools/testing/selftests/bpf/progs/test_ringbuf_write.c b/tools/testing/selftests/bpf/progs/test_ringbuf_write.c new file mode 100644 index 00000000000000..c6c67238a7c805 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_ringbuf_write.c @@ -0,0 +1,42 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include +#include "bpf_misc.h" + +char _license[] SEC("license") = "GPL"; + +struct { + __uint(type, BPF_MAP_TYPE_RINGBUF); +} ringbuf SEC(".maps"); + +long discarded, passed; +int pid; + +SEC("fentry/" SYS_PREFIX "sys_getpgid") +int test_ringbuf_write(void *ctx) +{ + int *foo, cur_pid = bpf_get_current_pid_tgid() >> 32; + void *sample1, *sample2; + + if (cur_pid != pid) + return 0; + + sample1 = bpf_ringbuf_reserve(&ringbuf, 0x3000, 0); + if (!sample1) + return 0; + /* first one can pass */ + sample2 = bpf_ringbuf_reserve(&ringbuf, 0x3000, 0); + if (!sample2) { + bpf_ringbuf_discard(sample1, 0); + __sync_fetch_and_add(&discarded, 1); + return 0; + } + /* second one must not */ + __sync_fetch_and_add(&passed, 1); + foo = sample2 + 4084; + *foo = 256; + bpf_ringbuf_discard(sample1, 0); + bpf_ringbuf_discard(sample2, 0); + return 0; +}