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| author | Zhouyi Zhou <zhouzhouyi@gmail.com> | 2013-10-24 15:43:33 +0800 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2013-10-28 16:06:00 -0300 |
| commit | 8e50d384cc1d5afd2989cf0f7093756ed7164eb2 (patch) | |
| tree | 87e34b49783a32d8552eaad510d0b5fba94ee08e /tools/perf/builtin-kvm.c | |
| parent | ae779a630977d93fbebfa06216ea47df5b5c62c8 (diff) | |
| download | op-kernel-dev-8e50d384cc1d5afd2989cf0f7093756ed7164eb2.zip op-kernel-dev-8e50d384cc1d5afd2989cf0f7093756ed7164eb2.tar.gz | |
perf tools: Fixup mmap event consumption
The tail position of the event buffer should only be modified after
actually use that event.
If not the event buffer could be invalid before use, and segment fault
occurs when invoking perf top -G.
Signed-off-by: Zhouyi Zhou <yizhouzhou@ict.ac.cn>
Cc: David Ahern <dsahern@gmail.com>
Cc: Zhouyi Zhou <yizhouzhou@ict.ac.cn>
Link: http://lkml.kernel.org/r/1382600613-32177-1-git-send-email-zhouzhouyi@gmail.com
[ Simplified the logic using exit gotos and renamed write_tail method to mmap_consume ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/builtin-kvm.c')
| -rw-r--r-- | tools/perf/builtin-kvm.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/tools/perf/builtin-kvm.c b/tools/perf/builtin-kvm.c index 935d522..fbc2888 100644 --- a/tools/perf/builtin-kvm.c +++ b/tools/perf/builtin-kvm.c @@ -888,11 +888,18 @@ static s64 perf_kvm__mmap_read_idx(struct perf_kvm_stat *kvm, int idx, while ((event = perf_evlist__mmap_read(kvm->evlist, idx)) != NULL) { err = perf_evlist__parse_sample(kvm->evlist, event, &sample); if (err) { + perf_evlist__mmap_consume(kvm->evlist, idx); pr_err("Failed to parse sample\n"); return -1; } err = perf_session_queue_event(kvm->session, event, &sample, 0); + /* + * FIXME: Here we can't consume the event, as perf_session_queue_event will + * point to it, and it'll get possibly overwritten by the kernel. + */ + perf_evlist__mmap_consume(kvm->evlist, idx); + if (err) { pr_err("Failed to enqueue sample: %d\n", err); return -1; |
