Messages in this thread | | | Date | Mon, 2 Nov 2020 17:56:26 +0100 | From | Jiri Olsa <> | Subject | Re: [PATCH v2 2/2] perf lock: Don't free "lock_seq_stat" if read_count isn't zero |
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On Wed, Oct 21, 2020 at 08:39:48AM +0800, Leo Yan wrote: > 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> > --- > tools/perf/builtin-lock.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > 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++;
it seems ok, but I fail to see what's nr_release for the point is just to skip the removal of seq right?
jirka
> goto end; > } > -- > 2.17.1 >
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