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 8926A6BFCE; Sun, 24 Mar 2024 17:07:46 +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=1711300066; cv=none; b=mqs7sbK3+wNCBZUX8ZhI6Vj+T3Pa4yjq1JsyjiE2W45NTv7cvKVkdkyqhjVBYgTrgD8Bjkz+cjij9ZZ6z2kcQjDVCcRdDcJfQHxhPCt7fSJgxZwrsdUtc7DwV8tNWVuPLKT1ObRnMFGwCEyoZOwfILMvHuEF3alQVX65yQ744jA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711300066; c=relaxed/simple; bh=fwh2m7sCn29cG90OCu3PIuTxTxnWk5RXZjAseQsIl/Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=j5oz+2eGikJDgpe6xS2hs++XCSSIxhQewuZaKql9ZbKg31SmBwqO8LcSi21VpBzrsDUMPK6xWSnwOp+8LunZ17T13uvlBDmD0yfYcW6PelZ7qb+3wHjKvPmWwStI4MOLKOT20aMXWqM1LyUUZJhp/PdhLjhnjBwzhp8PcWvgr7U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=VVhSEMVl; 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="VVhSEMVl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 92380C433A6; Sun, 24 Mar 2024 17:07:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711300066; bh=fwh2m7sCn29cG90OCu3PIuTxTxnWk5RXZjAseQsIl/Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VVhSEMVlezb5LZIrxLbfT+qdL7l9a8+wo8/Z/ZzXhhf8w6T6QB9e6w02CYViDMM/C aIW7pmISbfdz1rv2IeOfQzXTzm+vLvqv8nq1Li/bMDIa7B5i3figc4iGQsKDnkr8vY 3tk4+i+FQoAmzxcNJX4iQWZowKDd1rBnEl8vSg8Rk3hZX4SA8y2+rG61m1smA+keyE 1Rc8bp+U1jnMQ5ksMR2W91Y2QcBSVP3drTxSLHalCbajWebZ5T/oN/1BHpev289vCu +/Q1rRbj7Lrb8I030a3hKVjT5epiQrztsYs/Op05WViiRCMARhqdmSBYZvvi52wL2u lBkNtpoLwJIrg== 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 4.19 2/2] block: prevent division by zero in blk_rq_stat_sum() Date: Sun, 24 Mar 2024 13:07:41 -0400 Message-ID: <20240324170743.546858-2-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240324170743.546858-1-sashal@kernel.org> References: <20240324170743.546858-1-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 4.19.310 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 7587b1c3caaf5..507ac714423bd 100644 --- a/block/blk-stat.c +++ b/block/blk-stat.c @@ -27,7 +27,7 @@ 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