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authorLeo Yan <leo.yan@linaro.org>2020-11-04 12:42:29 +0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2020-11-12 23:55:41 +0300
commitb0e5a05cc9e37763c7f19366d94b1a6160c755bc (patch)
treec18d260b13c73d8bcc13ef1265497c434df67109 /tools
parente24a87b54ef3e39261f1d859b7f78416349dfb14 (diff)
downloadlinux-b0e5a05cc9e37763c7f19366d94b1a6160c755bc.tar.xz
perf lock: Don't free "lock_seq_stat" if read_count isn't zero
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>
Diffstat (limited to 'tools')
-rw-r--r--tools/perf/builtin-lock.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
index 5cecc1ad78e1..a2f1e53f37a7 100644
--- a/tools/perf/builtin-lock.c
+++ b/tools/perf/builtin-lock.c
@@ -621,7 +621,7 @@ static int report_lock_release_event(struct 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;
}