From: Leo Yan <leo.yan@linaro.org>
To: Arnaldo Carvalho de Melo <acme@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] perf lock: Don't free "lock_seq_stat" if read_count isn't zero
Date: Wed, 21 Oct 2020 08:42:23 +0800 [thread overview]
Message-ID: <20201021004223.GA7226@leoy-ThinkPad-X240s> (raw)
In-Reply-To: <20201021002619.28072-2-leo.yan@linaro.org>
Hi all,
On Wed, Oct 21, 2020 at 08:26:19AM +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".
Please ignore this patch set and directly to review patch set v2; I
forgot adding "fixes" tag in this patch, so updated in patch set v2.
Sorry for spamming.
Leo
prev parent reply other threads:[~2020-10-21 0:42 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-21 0:26 [PATCH 1/2] perf lock: Correct field name "flags" Leo Yan
2020-10-21 0:26 ` [PATCH 2/2] perf lock: Don't free "lock_seq_stat" if read_count isn't zero Leo Yan
2020-10-21 0:42 ` Leo Yan [this message]
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