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 v5 bpf-next 0/5] bpf: fix stackmap on perf_events with PEBS
Date: Thu, 23 Jul 2020 11:06:43 -0700 [thread overview]
Message-ID: <20200723180648.1429892-1-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 v4 => v5:
1. Return -EPROTO instead of -EINVAL on PERF_EVENT_IOC_SET_BPF errors.
(Alexei)
2. Let libbpf print a hint message when PERF_EVENT_IOC_SET_BPF returns
-EPROTO. (Alexei)
Changes v3 => v4:
1. Fix error check logic in bpf_get_stackid_pe and bpf_get_stack_pe.
(Alexei)
2. Do not allow attaching BPF programs with bpf_get_stack|stackid to
perf_event with precise_ip > 0, but not proper callchain. (Alexei)
3. Add selftest get_stackid_cannot_attach.
Changes v2 => v3:
1. Fix handling of stackmap skip field. (Andrii)
2. Simplify the code in a few places. (Andrii)
Changes v1 => v2:
1. Simplify the design and avoid introducing new helper function. (Andrii)
Song Liu (5):
bpf: separate bpf_get_[stack|stackid] for perf events BPF
bpf: fail PERF_EVENT_IOC_SET_BPF when bpf_get_[stack|stackid] cannot
work
libbpf: print hint when PERF_EVENT_IOC_SET_BPF returns -EPROTO
selftests/bpf: add callchain_stackid
selftests/bpf: add get_stackid_cannot_attach
include/linux/bpf.h | 2 +
include/linux/filter.h | 3 +-
kernel/bpf/stackmap.c | 184 ++++++++++++++++--
kernel/bpf/verifier.c | 3 +
kernel/events/core.c | 18 ++
kernel/trace/bpf_trace.c | 4 +-
tools/lib/bpf/libbpf.c | 3 +
.../prog_tests/get_stackid_cannot_attach.c | 91 +++++++++
.../bpf/prog_tests/perf_event_stackmap.c | 116 +++++++++++
.../selftests/bpf/progs/perf_event_stackmap.c | 59 ++++++
10 files changed, 462 insertions(+), 21 deletions(-)
create mode 100644 tools/testing/selftests/bpf/prog_tests/get_stackid_cannot_attach.c
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:[~2020-07-23 18:10 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-23 18:06 Song Liu [this message]
2020-07-23 18:06 ` [PATCH v5 bpf-next 1/5] bpf: separate bpf_get_[stack|stackid] for perf events BPF Song Liu
2020-07-23 18:06 ` [PATCH v5 bpf-next 2/5] bpf: fail PERF_EVENT_IOC_SET_BPF when bpf_get_[stack|stackid] cannot work Song Liu
2020-07-23 18:06 ` [PATCH v5 bpf-next 3/5] libbpf: print hint when PERF_EVENT_IOC_SET_BPF returns -EPROTO Song Liu
2020-07-23 18:06 ` [PATCH v5 bpf-next 4/5] selftests/bpf: add callchain_stackid Song Liu
2020-07-23 18:06 ` [PATCH v5 bpf-next 5/5] selftests/bpf: add get_stackid_cannot_attach Song Liu
2020-07-24 5:32 ` Alexei Starovoitov
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