bpf: Separate bpf_get_[stack|stackid] for perf events BPF

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Calling get_perf_callchain() on perf_events from PEBS entries may cause
unwinder errors. To fix this issue, the callchain is fetched early. Such
perf_events are marked with __PERF_SAMPLE_CALLCHAIN_EARLY.

Similarly, calling bpf_get_[stack|stackid] on perf_events from PEBS may
also cause unwinder errors. To fix this, add separate version of these
two helpers, bpf_get_[stack|stackid]_pe. These two hepers use callchain in
bpf_perf_event_data_kern->data->callchain.

Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200723180648.1429892-2-songliubraving@fb.com

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Song Liu 2020-07-23 11:06:44 -07:00 • committed by Alexei Starovoitov

parent 909e446b32

commit 7b04d6d60f

3 changed files with 170 additions and 20 deletions

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2

include/linux/bpf.h

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184

kernel/bpf/stackmap.c

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4

kernel/trace/bpf_trace.c

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