From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6B859C4332F for ; Thu, 14 Apr 2022 01:23:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239430AbiDNB0C (ORCPT ); Wed, 13 Apr 2022 21:26:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56914 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229875AbiDNB0A (ORCPT ); Wed, 13 Apr 2022 21:26:00 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C562152B39 for ; Wed, 13 Apr 2022 18:23:37 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 4B83961AA0 for ; Thu, 14 Apr 2022 01:23:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 82050C385A3; Thu, 14 Apr 2022 01:23:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1649899416; bh=2gDG2+FMjzNamReNAqV/v1d3JwqgZuw1ddRLn9TCjhw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=eOLqVMdQAa9hywnzp6hidDX7SZjrL2PvjXbDmgj/MeqKs5LUxYS0nPuwGOGBe5KlA UsZzVcJzY4gQn2tr0Qb3MVcADCqFWMbdY1A2YRNWLXPFPVAabJgNoHgNN2KUQPeA13 YMjvC4qB8K6kODvg9diqAMs8uXGGCGIVgqLGBkFGVfV+lsrMM5vuj9h2ouSUUx5udb R0Wjh/2BuMqgnPzvKrLFVA9EJB5owanBIXR+DixRTLZ9kRPxU2X2oizJ3z8kaXAIWS hdjVbC22Q3IvOS3JCc90L1y4tBcLZ7yXe2J/UiDuO2CWx7LOIV4dL/yePdkRHEHIto 7McIuBe3prSeQ== Received: by quaco.ghostprotocols.net (Postfix, from userid 1000) id A4DB640407; Wed, 13 Apr 2022 22:23:32 -0300 (-03) Date: Wed, 13 Apr 2022 22:23:32 -0300 From: Arnaldo Carvalho de Melo To: Ian Rogers Cc: Adrian Hunter , Jiri Olsa , linux-kernel@vger.kernel.org Subject: Re: [PATCH] perf tools: Fix segfault accessing sample_id xyarray Message-ID: References: <20220413114232.26914-1-adrian.hunter@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Url: http://acmel.wordpress.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Wed, Apr 13, 2022 at 02:11:41PM -0700, Ian Rogers escreveu: > On Wed, Apr 13, 2022 at 4:42 AM Adrian Hunter wrote: > > > > perf_evsel sample_id is an xyarray which can cause a segfault when > > accessed beyond its size. e.g. > > > > # perf record -e intel_pt// -C 1 sleep 1 > > Segmentation fault (core dumped) > > > > That is happening because a dummy event is opened to capture text poke > > events accoss all CPUs, however the mmap logic is allocating according > > to the number of user_requested_cpus. > > Nit: typo on 'accoss' Fixed > > In general, perf sometimes uses the evsel cpus to open events, and > > sometimes the evlist user_requested_cpus. However, it is not necessary > > to determine which case is which because the opened event file > > descriptors are also in an xyarray, the size of whch can be used > > to correctly allocate the size of the sample_id xyarray, because there > > is one ID per file descriptor. Note, in the affected code path, > > perf_evsel fd array is subsequently used to get the file descriptor for > > the mmap, so it makes sense for the xyarrays to be the same size there. > > > > Fixes: 246eba8e9041c4 ("perf tools: Add support for PERF_RECORD_TEXT_POKE") > > Fixes: d1a177595b3a82 ("libperf: Adopt perf_evlist__mmap()/munmap() from tools/perf") > > Cc: stable@vger.kernel.org # 5.5+ > > Signed-off-by: Adrian Hunter > > Acked-by: Ian Rogers Thanks, applied. - Arnaldo > Thanks, > Ian > > > --- > > tools/lib/perf/evlist.c | 3 +-- > > 1 file changed, 1 insertion(+), 2 deletions(-) > > > > diff --git a/tools/lib/perf/evlist.c b/tools/lib/perf/evlist.c > > index 1b15ba13c477..a09315538a30 100644 > > --- a/tools/lib/perf/evlist.c > > +++ b/tools/lib/perf/evlist.c > > @@ -577,7 +577,6 @@ int perf_evlist__mmap_ops(struct perf_evlist *evlist, > > { > > struct perf_evsel *evsel; > > const struct perf_cpu_map *cpus = evlist->user_requested_cpus; > > - const struct perf_thread_map *threads = evlist->threads; > > > > if (!ops || !ops->get || !ops->mmap) > > return -EINVAL; > > @@ -589,7 +588,7 @@ int perf_evlist__mmap_ops(struct perf_evlist *evlist, > > perf_evlist__for_each_entry(evlist, evsel) { > > if ((evsel->attr.read_format & PERF_FORMAT_ID) && > > evsel->sample_id == NULL && > > - perf_evsel__alloc_id(evsel, perf_cpu_map__nr(cpus), threads->nr) < 0) > > + perf_evsel__alloc_id(evsel, evsel->fd->max_x, evsel->fd->max_y) < 0) > > return -ENOMEM; > > } > > > > -- > > 2.25.1 > > -- - Arnaldo