From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 59D96284B50; Wed, 28 May 2025 12:51:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748436670; cv=none; b=DdkGwa1VyWLk7nMfmOqDArRfnEmJ7RvDTASrw3Xpp0mnFbMe+6/txdzBAk/jlHs+vIxtrekoinMD1o64fsw63u3tkGar6aTJLxR7JhZgFAwtN18mLTz93sKNKWCN9yhmw1pFNjzeeIwNUkwhkHZEnMpEopXfgP84nu0NB2zBRP8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748436670; c=relaxed/simple; bh=cLH9qffAGEku8VAcA1NrwyVqoqY9fO9tSWVZlmurDRk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=NJ2VGlJNSDGclZGEoHKT2duGyN8kF/vCDIUw/WYcgf7zorj+Xli+/l/P83aUH8IIf6zvwiWg8QV4gsDzRSBL5iW+YFq9yzG/Q1x/kXubKsz1N5Bq1CXvXOIWAIPbnn1po9YVQRGfq9uSYTGlECquXsAlvFa6+qXtrA8RPNSmjBk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=rCl0VbJJ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="rCl0VbJJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3B976C4CEED; Wed, 28 May 2025 12:51:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1748436669; bh=cLH9qffAGEku8VAcA1NrwyVqoqY9fO9tSWVZlmurDRk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=rCl0VbJJYSTxtsSM0wq5JtaYgNdWBxXSGev4c807eFT2cV0Gk7WtBct0tOIb4NUYd 3+TAXbamprgrXeBEJltFYsgApJkycB2LPzp5v6k26B3D2f6nLoTTK5y/vTDSmTYisT S265Obji7Ruw1g/U4o/KtKC1WsqV/R3ZqWcAOQySG8d9RZUtw9XxClmxNLCRw56o5X S8EEquEI1YYGqGwe/JYbUY5PGI8kl929Q/FNLe3cqCbGkx7AJ3WY0wPrW7ADja9QWQ MxjZoH2mUsUGdY/+oEQdhE/MMFVPnmCDt2JglVpzlN8FS/2fkl9RiSu41y1ysQVRGs qmIy29xfDUx0g== Date: Wed, 28 May 2025 09:51:06 -0300 From: Arnaldo Carvalho de Melo To: Ian Rogers Cc: Peter Zijlstra , Ingo Molnar , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Adrian Hunter , Kan Liang , Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?iso-8859-1?Q?Bj=F6rn?= Roy Baron , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Jiapeng Chong , James Clark , Howard Chu , Weilin Wang , Stephen Brennan , Andi Kleen , Dmitry Vyukov , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v1 4/6] perf intel-tpebs: Avoid race when evlist is being deleted Message-ID: References: <20250527180703.129336-1-irogers@google.com> <20250527180703.129336-5-irogers@google.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250527180703.129336-5-irogers@google.com> On Tue, May 27, 2025 at 11:07:01AM -0700, Ian Rogers wrote: > Reading through the evsel->evlist may seg fault if a sample arrives > when the evlist is being deleted. Detect this case and ignore samples > arriving when the evlist is being deleted. Thanks, applied to perf-tools-next, - Arnaldo > Fixes: bcfab08db7fb ("perf intel-tpebs: Filter non-workload samples") > Signed-off-by: Ian Rogers > --- > tools/perf/util/intel-tpebs.c | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/tools/perf/util/intel-tpebs.c b/tools/perf/util/intel-tpebs.c > index 4ad4bc118ea5..3b92ebf5c112 100644 > --- a/tools/perf/util/intel-tpebs.c > +++ b/tools/perf/util/intel-tpebs.c > @@ -162,9 +162,17 @@ static bool is_child_pid(pid_t parent, pid_t child) > > static bool should_ignore_sample(const struct perf_sample *sample, const struct tpebs_retire_lat *t) > { > - pid_t workload_pid = t->evsel->evlist->workload.pid; > - pid_t sample_pid = sample->pid; > + pid_t workload_pid, sample_pid = sample->pid; > > + /* > + * During evlist__purge the evlist will be removed prior to the > + * evsel__exit calling evsel__tpebs_close and taking the > + * tpebs_mtx. Avoid a segfault by ignoring samples in this case. > + */ > + if (t->evsel->evlist == NULL) > + return true; > + > + workload_pid = t->evsel->evlist->workload.pid; > if (workload_pid < 0 || workload_pid == sample_pid) > return false; > > -- > 2.49.0.1204.g71687c7c1d-goog