From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793133453; b=EWcmxrtFTvE+OXNlUaRYaRTANNBs0QKB1wa+XEgHYsOdFvnUteYCld2xBUqrxaObKAB1 SblGc6gV18ZTQZz/zcMyN3ystw54ipHLJYN1sTFmgdBPG5vRlaKf9aHsjkaaRC/lgyCiq ihSETjmfn5EKNuzy2XJ4Q2wGTBYV8EdwyZsB7pG7H4DJ0nvf5fa4Vcscuc0ih4tRQc+Oa 8JO6sr96SXX+sUMhigkA1ep7eDXP8P8P4YshdD+/z8vNVoN9l1RBOfYGHCkPw6UeHHPxK v3HlkQVkgMtwmEKWfPIN+Fum5TQp/udRk7UHT7zj011zw6Cx0ZyuahgQDmWJQ3K6hrQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793133453; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-ID: References:MIME-Version:Content-Type:Content-Disposition: Content-Transfer-Encoding:In-Reply-To; bh=wUv2shmSnp3EKpQLizhxLT20/UDWKKocXenHDKyrGK0=; b=WLRn4EXTvSRJVp+jd5/AnWGrX0mOEHPRLQOf/xTdlwu7HQLFEo1GvQ46GWHp35kcLHV/ 0h4Tgbvk2M+YWXCcr8007/OiKN8z05Yo8IMyZO1dAEBGcpibiYR0Epl8xB/5VnCIgKtAg gWthnTb67k/KjultTj1tEsRMKnCFt/0SJjEHu64LIMYmC92KX1K7aRDOnEobJBJhcyaMR 97kRfAoX4l1nfOK/xZi2C2b6+W94EMz1VxCsn3lbUnflw7Kx7m9n9UZ4lVTZM02y/GLYE VyPJiP1r0EWcd8oF2MjY6XsZiVc9pQxNgdXthUd0YjdXz8ZHpCcdsqw3r2abX8lh43g== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=XNuZTYRU; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BE01E606A31A; Tue, 27 Oct 2026 20:37:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=XNuZTYRU Received: by smtp.kernel.org (Postfix) with ESMTPSA id C73F31F01825; Tue, 27 Oct 2026 20:37:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793133452; bh=wUv2shmSnp3EKpQLizhxLT20/UDWKKocXenHDKyrGK0=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=XNuZTYRUhFIfqgBAa5IwJ+aEhapNxOJ6L/8Y/USHryvJNiBhpKSmrjbhzjFTtSwuS jAeoFYlJO6AKdm06N7r5SnRMqYc+U3G0+5/og3DS62czFxyiUApuCQip2ERCo2I4md 47NaqmkvzqTedhcTyTcTgFaGqJP7Yuy/19wQNqwc02ZLwrIPX2CnyFvXXo6VrAJ5ga ambIg6mvv5gaBudoBQ5QJN8a/Eks//bC1dIkdNHCTIadEqXli2vtCgbSkTq2ULUgZR v2DdFlP3wk4YgCOq5gPe9XY00TafymmJAQ/9qMv+hyHjzCHRJYpaHkevOiTLFwRIbM iOFYMDj+drckg== Date: Tue, 27 Oct 2026 17:37:29 -0300 From: Arnaldo Carvalho de Melo To: Ian Rogers Cc: lv.yating@zte.com.cn, peterz@infradead.org, mingo@redhat.com, namhyung@kernel.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@kernel.org, adrian.hunter@intel.com, james.clark@linaro.org, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, liu.qingtao2@zte.com.cn, he.yilin@zte.com.cn, zhang.cheng35@zte.com.cn, ye.zhihao1@zte.com.cn, shen.lin1@zte.com.cn, dai.hualiang@zte.com.cn, stable@vger.kernel.org, hu.shengming@zte.com.cn Subject: Re: [PATCH] perf machine: Fix NULL deref in thread__resolve_callchain_sample() Message-ID: References: <202610271154.69RBsOlq045164@mse-fl2.zte.com.cn> X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Tue, Oct 27, 2026 at 08:21:16AM -0700, Ian Rogers wrote: > On Tue, Oct 27, 2026 at 4:54 AM wrote: > > When recording with -j stack, resolve_lbr_callchain_sample() can > > dereference a NULL 'chain' pointer while resolving the branch > > stack. > > $ perf record -j stack -e branches:u uname > > perf: Segmentation fault > > Fix it by checking 'chain' for NULL before dereferencing it. > > Fixes: 29be60c93d2d ("perf build-id: Mark DSO in sample callchains") > > Signed-off-by: lvyating > > Cc: stable@vger.kernel.org > Tested-by: Ian Rogers > Reviewed-by: Ian Rogers Thanks, applied for v7.4. > I wonder - this failure points to a lack of test coverage. For LBR the > main coverage comes from: > https://web.git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git/tree/tools/perf/tests/shell/record_lbr.sh?h=perf-tools-next > Could you help expand the tests to avoid regressions? That would be great indeed, - Arnaldo