From: Song Liu <songliubraving@fb.com>
To: <linux-kernel@vger.kernel.org>, <bpf@vger.kernel.org>,
<netdev@vger.kernel.org>
Cc: <ast@kernel.org>, <daniel@iogearbox.net>, <kernel-team@fb.com>,
<john.fastabend@gmail.com>, <kpsingh@chromium.org>,
<brouer@redhat.com>, <peterz@infradead.org>,
Song Liu <songliubraving@fb.com>
Subject: [PATCH v2 bpf-next 0/2] bpf: fix stackmap on perf_events with PEBS
Date: Tue, 14 Jul 2020 22:25:59 -0700 [thread overview]
Message-ID: <20200715052601.2404533-1-songliubraving@fb.com> (raw)
Calling get_perf_callchain() on perf_events from PEBS entries may cause
unwinder errors. To fix this issue, perf subsystem fetches callchain early,
and marks perf_events are marked with __PERF_SAMPLE_CALLCHAIN_EARLY.
Similar issue exists when BPF program calls get_perf_callchain() via
helper functions. For more information about this issue, please refer to
discussions in [1].
This set fixes this issue with helper proto bpf_get_stackid_pe and
bpf_get_stack_pe.
[1] https://lore.kernel.org/lkml/ED7B9430-6489-4260-B3C5-9CFA2E3AA87A@fb.com/
Changes v1 => v2:
1. Simplify the design and avoid introducing new helper function. (Andrii)
Song Liu (2):
bpf: separate bpf_get_[stack|stackid] for perf events BPF
selftests/bpf: add callchain_stackid
include/linux/bpf.h | 2 +
kernel/bpf/stackmap.c | 204 ++++++++++++++++--
kernel/trace/bpf_trace.c | 4 +-
.../bpf/prog_tests/perf_event_stackmap.c | 120 +++++++++++
.../selftests/bpf/progs/perf_event_stackmap.c | 64 ++++++
5 files changed, 374 insertions(+), 20 deletions(-)
create mode 100644 tools/testing/selftests/bpf/prog_tests/perf_event_stackmap.c
create mode 100644 tools/testing/selftests/bpf/progs/perf_event_stackmap.c
--
2.24.1
next reply other threads:[~2020-07-15 5:29 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-15 5:25 Song Liu [this message]
2020-07-15 5:26 ` [PATCH v2 bpf-next 1/2] bpf: separate bpf_get_[stack|stackid] for perf events BPF Song Liu
2020-07-16 5:55 ` Andrii Nakryiko
2020-07-17 1:07 ` kernel test robot
2020-07-15 5:26 ` [PATCH v2 bpf-next 2/2] selftests/bpf: add callchain_stackid Song Liu
2020-07-16 6:04 ` Andrii Nakryiko
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