From: Jiri Olsa <jolsa@kernel.org>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>,
lkml <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Mark Rutland <mark.rutland@arm.com>,
Namhyung Kim <namhyung@kernel.org>,
bpf@vger.kernel.org, Song Liu <songliubraving@fb.com>,
Daniel Xu <dxu@dxuuu.xyz>
Subject: [PATCH -tip] bpf: Check flags for branch stack in bpf_read_branch_records helper
Date: Tue, 27 Sep 2022 22:32:59 +0200 [thread overview]
Message-ID: <20220927203259.590950-1-jolsa@kernel.org> (raw)
Recent commit [1] changed branch stack data indication from
br_stack pointer to sample_flags in perf_sample_data struct.
We need to check sample_flags for PERF_SAMPLE_BRANCH_STACK
bit for valid branch stack data.
[1] a9a931e26668 ("perf: Use sample_flags for branch stack")
Cc: Kan Liang <kan.liang@linux.intel.com>
Fixes: a9a931e26668 ("perf: Use sample_flags for branch stack")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
NOTE sending on top of tip/master because [1] is not
merged in bpf-next/master yet
kernel/trace/bpf_trace.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 68e5cdd24cef..1fcd1234607e 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1507,6 +1507,9 @@ BPF_CALL_4(bpf_read_branch_records, struct bpf_perf_event_data_kern *, ctx,
if (unlikely(flags & ~BPF_F_GET_BRANCH_RECORDS_SIZE))
return -EINVAL;
+ if (unlikely(!(ctx->data->sample_flags & PERF_SAMPLE_BRANCH_STACK)))
+ return -ENOENT;
+
if (unlikely(!br_stack))
return -ENOENT;
--
2.37.3
next reply other threads:[~2022-09-27 20:33 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-27 20:32 Jiri Olsa [this message]
2022-09-27 20:41 ` [PATCH -tip] bpf: Check flags for branch stack in bpf_read_branch_records helper Liang, Kan
2022-09-27 20:46 ` Peter Zijlstra
2022-09-27 21:24 ` Jiri Olsa
2022-09-27 21:49 ` Song Liu
2022-09-27 21:50 ` Song Liu
2022-09-28 6:57 ` [tip: perf/core] " tip-bot2 for Jiri Olsa
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