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| author | Namhyung Kim <namhyung@kernel.org> | 2024-04-10 01:55:42 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-04-27 18:12:54 +0300 |
| commit | 1dbd4215c764c3af72b882d784d1c01947b1a15e (patch) | |
| tree | 53d32d8d43618f3457297cd9fd4c4a88aa02dad2 | |
| parent | 6450c4f23ccdc3db241d5bb44d9d0f26b7e5faf3 (diff) | |
| download | linux-1dbd4215c764c3af72b882d784d1c01947b1a15e.tar.xz | |
perf lock contention: Add a missing NULL check
[ Upstream commit f3408580bac8ce5cd76e7391e529c0a22e7c7eb2 ]
I got a report for a failure in BPF verifier on a recent kernel with
perf lock contention command. It checks task->sighand->siglock without
checking if sighand is NULL or not. Let's add one.
; if (&curr->sighand->siglock == (void *)lock)
265: (79) r1 = *(u64 *)(r0 +2624) ; frame1: R0_w=trusted_ptr_task_struct(off=0,imm=0)
; R1_w=rcu_ptr_or_null_sighand_struct(off=0,imm=0)
266: (b7) r2 = 0 ; frame1: R2_w=0
267: (0f) r1 += r2
R1 pointer arithmetic on rcu_ptr_or_null_ prohibited, null-check it first
processed 164 insns (limit 1000000) max_states_per_insn 1 total_states 15 peak_states 15 mark_read 5
-- END PROG LOAD LOG --
libbpf: prog 'contention_end': failed to load: -13
libbpf: failed to load object 'lock_contention_bpf'
libbpf: failed to load BPF skeleton 'lock_contention_bpf': -13
Failed to load lock-contention BPF skeleton
lock contention BPF setup failed
lock contention did not detect any lock contention
Fixes: 1811e82767dcc ("perf lock contention: Track and show siglock with address")
Reviewed-by: Ian Rogers <irogers@google.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Song Liu <song@kernel.org>
Cc: bpf@vger.kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240409225542.1870999-1-namhyung@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | tools/perf/util/bpf_skel/lock_contention.bpf.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/tools/perf/util/bpf_skel/lock_contention.bpf.c b/tools/perf/util/bpf_skel/lock_contention.bpf.c index 95cd8414f6ef..e5d78565f479 100644 --- a/tools/perf/util/bpf_skel/lock_contention.bpf.c +++ b/tools/perf/util/bpf_skel/lock_contention.bpf.c @@ -289,6 +289,7 @@ static inline __u32 check_lock_type(__u64 lock, __u32 flags) struct task_struct *curr; struct mm_struct___old *mm_old; struct mm_struct___new *mm_new; + struct sighand_struct *sighand; switch (flags) { case LCB_F_READ: /* rwsem */ @@ -310,7 +311,9 @@ static inline __u32 check_lock_type(__u64 lock, __u32 flags) break; case LCB_F_SPIN: /* spinlock */ curr = bpf_get_current_task_btf(); - if (&curr->sighand->siglock == (void *)lock) + sighand = curr->sighand; + + if (sighand && &sighand->siglock == (void *)lock) return LCD_F_SIGHAND_LOCK; break; default: |