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 4C2EA1B9F5B; Fri, 29 Mar 2024 12:50:47 +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=1711716647; cv=none; b=mNWA+mv0k1P/McqGRHDr7+qTnig6n19KGrzse9Vj7EFyF2PzkphcsluNBe1rtLOXZvRy7xk6FP82sy07nmn+/OFiomMWPAzmksPBClyYnRzq0hPMdQPwaGYlt22juk1pCAuVMfmwiS4DgaX9P5pbfF+Yg3uhayioyCGetcJjzy4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711716647; c=relaxed/simple; bh=dfl4B/oMFy0pf7PoHFZ/dpH6YryXARkBv/Ll0Q4yQLo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=McSq9k7FAJuwlnxC9trqsmzdH1WP6wChAZp7bNBGbXgbp0fcqPTAcCEGkGR5k9n2piJjZJRk97qG8ps+XIM71DHWZaNPpamfdCEIykglffEFvXnePV5Vg3oCJRwhFN80hbfGKBcTRu1IP8Ls25CACMFgZTFI+t1esej6xLWDvR4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kaFAEigd; 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="kaFAEigd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5875BC433B1; Fri, 29 Mar 2024 12:50:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711716647; bh=dfl4B/oMFy0pf7PoHFZ/dpH6YryXARkBv/Ll0Q4yQLo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kaFAEigd6ol45LM6vPEBu0FNimS6sJ17gZD+eZ0dBx1VnOe3lW74R9Rl5+fywmBxn bhersesu3RfD+pDaTdukvQIhRJu2fgNysF3uoMI4CshePNGXmbjTA+1JP3XY+s1L7t ko6GwS3r0JcRyg8QyVxa1+eCvdmjg8QKxrgcQx9LbROxVBul7ttwfhJ0lhi/136wqJ oU2Q59UiNyFAcgAaW452MJ9lYSB1i8dNVYG6PzXHtrK/srXu78NamDGvUY+agooY/n w8OQjjhhtlOnDbir3hCGIzHytZlubKLhcEsTONaETV4KQuPKykaFDk6JnV3hCK1dik 7uCjj8kr9BD9w== 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 5.4 21/23] block: prevent division by zero in blk_rq_stat_sum() Date: Fri, 29 Mar 2024 08:49:54 -0400 Message-ID: <20240329125009.3093845-21-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240329125009.3093845-1-sashal@kernel.org> References: <20240329125009.3093845-1-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 5.4.273 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 940f15d600f8a..af482d8f9f7a4 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