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| author | Leo Yan <leo.yan@linaro.org> | 2020-11-04 17:42:29 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-11-24 12:48:11 +0100 |
| commit | 8c1a6a13f146b7f0bbb24f8e7848e576a5ebf9ed (patch) | |
| tree | 3388e911550637bc6024fbb469980d36397ebac4 /tools | |
| parent | 84ee38c34aed267c53ec9d40500ca02071fa805d (diff) | |
perf lock: Don't free "lock_seq_stat" if read_count isn't zero
[ Upstream commit b0e5a05cc9e37763c7f19366d94b1a6160c755bc ]
When execute command "perf lock report", it hits failure and outputs log
as follows:
perf: builtin-lock.c:623: report_lock_release_event: Assertion `!(seq->read_count < 0)' failed.
Aborted
This is an imbalance issue. The locking sequence structure
"lock_seq_stat" contains the reader counter and it is used to check if
the locking sequence is balance or not between acquiring and releasing.
If the tool wrongly frees "lock_seq_stat" when "read_count" isn't zero,
the "read_count" will be reset to zero when allocate a new structure at
the next time; thus it causes the wrong counting for reader and finally
results in imbalance issue.
To fix this issue, if detects "read_count" is not zero (means still have
read user in the locking sequence), goto the "end" tag to skip freeing
structure "lock_seq_stat".
Fixes: e4cef1f65061 ("perf lock: Fix state machine to recognize lock sequence")
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Link: https://lore.kernel.org/r/20201104094229.17509-2-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/perf/builtin-lock.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c index de16aaed516e..daf2dc023245 100644 --- a/tools/perf/builtin-lock.c +++ b/tools/perf/builtin-lock.c @@ -616,7 +616,7 @@ static int report_lock_release_event(struct perf_evsel *evsel, case SEQ_STATE_READ_ACQUIRED: seq->read_count--; BUG_ON(seq->read_count < 0); - if (!seq->read_count) { + if (seq->read_count) { ls->nr_release++; goto end; } |