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 217D55C911; Sun, 24 Mar 2024 17:07:27 +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=1711300047; cv=none; b=S0O8SQn5M03GR6624ePBIuNGeWU95DxxctC+vmkqpYKZNgyg0U4H3P2e9P4W29PdzZWGT+0JUJdnkG0LVrex8gyH2YGnfo4RFy70geIsOb/UqoipIoRmmK/qbzXamAfbe1VaqfIVpjGI2dMpyeDsOBgm9w/W58/jfbyUZIGplM0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711300047; c=relaxed/simple; bh=8wYWk+lnFSA1f2NjZ4HWprJzO1phQiGDLipkeklGi8o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=dpno1KISq2HPIgMwibeJhaTDLOgzZwarMTx3UcG2sIyyiZ14dofUDYfPRNOczbgu0B4NpEa0eiDbXT3NpP/BJCUIPSJagyYroXU/wlKVTwW8k0OdMrJ1ylhWnA7PqfRrbFGk94nj8MAppeRoMLZz1ZeanaD1tu3VPQhkXwpoTnw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=m3aOr89c; 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="m3aOr89c" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3227EC433A6; Sun, 24 Mar 2024 17:07:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711300047; bh=8wYWk+lnFSA1f2NjZ4HWprJzO1phQiGDLipkeklGi8o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=m3aOr89cCIjamz1LAElFZ+F7k9dml16ZYpAdUKfVUeGC2EH89Jl50S2ClQlmc74O1 Vspa6ewxwtBdKM2XSkJQvdjLYUsOGg3Z84d3mWvY6gQm6RFU0CozIFHIQ6M71LHjQW ZbZ/E+DFm0GZJnBJ83le+Y0j1Ghp2YpRuUAwIp2oPjWmWqR+oHHZiEtt21Mff5CxQD a+ERsbs2oqvUVXw+D7cqnUYAydOWweDijCIbzeLNMwVUYcEDzRFuD2A2QWrBmOrRJj AZCC9lNMGOAg6nHhHhAuwgAYTQ1G/9PPp7UKTczUUF96syXItt3Twv8jsbkQppRw91 D+olhDStmXDrQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Roman Smirnov , Sergey Shtylyov , Jens Axboe , Sasha Levin , linux-block@vger.kernel.org Subject: [PATCH AUTOSEL 5.15 2/2] block: prevent division by zero in blk_rq_stat_sum() Date: Sun, 24 Mar 2024 13:07:21 -0400 Message-ID: <20240324170723.546623-2-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240324170723.546623-1-sashal@kernel.org> References: <20240324170723.546623-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 5.15.152 Content-Transfer-Encoding: 8bit From: Roman Smirnov [ Upstream commit 93f52fbeaf4b676b21acfe42a5152620e6770d02 ] The expression dst->nr_samples + src->nr_samples may have zero value on overflow. It is necessary to add a check to avoid division by zero. Found by Linux Verification Center (linuxtesting.org) with Svace. Signed-off-by: Roman Smirnov Reviewed-by: Sergey Shtylyov Link: https://lore.kernel.org/r/20240305134509.23108-1-r.smirnov@omp.ru Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- block/blk-stat.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/blk-stat.c b/block/blk-stat.c index ae3dd1fb8e61d..6e602f9b966e4 100644 --- a/block/blk-stat.c +++ b/block/blk-stat.c @@ -28,7 +28,7 @@ void blk_rq_stat_init(struct blk_rq_stat *stat) /* src is a per-cpu stat, mean isn't initialized */ void blk_rq_stat_sum(struct blk_rq_stat *dst, struct blk_rq_stat *src) { - if (!src->nr_samples) + if (dst->nr_samples + src->nr_samples <= dst->nr_samples) return; dst->min = min(dst->min, src->min); -- 2.43.0