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 627161C089A; Fri, 29 Mar 2024 12:51:31 +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=1711716693; cv=none; b=p/t2YvnvgRMS1x1AIso2yYKiezrXWrLgIeSCCt48yvW2oJhdepGMiRAJQgggUyRk7Qx5WStGF51RK8NVXATmlhAXE9rDBk/VhqlpxvWCpbLCNGlknE4kbeAjtttzDQx3hoTPKO0Mtd0YK3XP2zoIXqeh9ErcdPuIjg7q3L/tOhQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711716693; c=relaxed/simple; bh=fwh2m7sCn29cG90OCu3PIuTxTxnWk5RXZjAseQsIl/Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=AoEIwo/+rMmXhQfJ/8tePJHea7jfYRzQwIZ+fWEKF4Gq1uhvShEUNlDvm0BX+h1Bxittj5TZDpVNVUqLsrwIzhbf1jz2ihhuA8ZIDXUCY1kDRJbeWa320Pg1z6AeGWTS3z0IBa754sUGIoXcRqGctG8rSfENgE4BQ3ZLxYa2R3M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=c7h5Kl4q; 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="c7h5Kl4q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 24F54C433A6; Fri, 29 Mar 2024 12:51:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711716691; bh=fwh2m7sCn29cG90OCu3PIuTxTxnWk5RXZjAseQsIl/Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=c7h5Kl4qBrNDYVTaB0Ibj+/j+0dQ4P1n4IwVG0qmlAMSct0tmtwpzTRfGf+tzZvVD lykhtgRvL50OypiFYH6l4P40uHIIXXUT8M4AxiFLnKn6r7xWjYp46wFNFpfMS+s4q6 G2AvtxDP/uvFtB/QJbTBVUtWqC4C44Hw2AUca0c7vIwN+BgT6XVjruLeXJIzzaAUKx ZSlLoz2XF61Zz5NaIrM+K+ovNk4USkk9FSM1QZSUa4l7csYSMdyI039egry0IN0Mza Zu5/hcVaVkq9Hx+gqe6bKNr9VOZRMsMqkbbAKvcHOQYdbp79NjWI2wbuF7gw5q8eIZ Sdap+MnmqCMvQ== 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 17/19] block: prevent division by zero in blk_rq_stat_sum() Date: Fri, 29 Mar 2024 08:50:49 -0400 Message-ID: <20240329125100.3094358-17-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240329125100.3094358-1-sashal@kernel.org> References: <20240329125100.3094358-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 4.19.311 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