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 5444426B0BC; Thu, 13 Feb 2025 14:57:24 +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=1739458644; cv=none; b=KKNdYDArt/5BOshnfptAiHcDC2coUANQI0wHGRvvEqO0uspKvCPIpMtMeAXD/BOZPc3nf0VsCGnnZMMNdWUqJRJEeQoye381rkd6f16FkM/AoJ5ctdOFLu2sfYS38RhIH8fzwfZ1/e28rcsGfxTKKWGA6aqzXNA01oqxeltbXzY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739458644; c=relaxed/simple; bh=9R4JYlMq7hj/LHNe8jxsDotkO4DyR28/+8gau7yJ7eA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kXxnOZxv0ZmaqPU7GKKvE97+xjhv7mLeIrgWHmvdMSSKeonZkuRJ6BP/V+upQlf1hV2Sh4XVe0iLBZNR2HJv88OYJWSMu3bo8LBVav6tJJ/a6j5QKyr/ygLT588Vg5Hhjp+UX56IPVNzYzFXxRNA4sJGFeR6lX2byJdVb6+to6k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=s5nXUHIK; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="s5nXUHIK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id ABEEEC4CED1; Thu, 13 Feb 2025 14:57:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1739458644; bh=9R4JYlMq7hj/LHNe8jxsDotkO4DyR28/+8gau7yJ7eA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=s5nXUHIKhs4EWVLkSfbirEtJs7kEg52sJrovwaZcMgGhEFmaWzm1/SALdAeE/BkM6 usSP/ns7HtQnzZjKxKhYrsjSljdrY91KBJiO8E3TjU7l39XtOFjjr4cFRPfpCti9tF o9M2Dwr7aoxUPz7VcPVLY9+GBspJ2Qc87f2m+OIE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Kuan-Wei Chiu , Petr Mladek , Sasha Levin Subject: [PATCH 6.13 030/443] printk: Fix signed integer overflow when defining LOG_BUF_LEN_MAX Date: Thu, 13 Feb 2025 15:23:15 +0100 Message-ID: <20250213142441.787453956@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250213142440.609878115@linuxfoundation.org> References: <20250213142440.609878115@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.13-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kuan-Wei Chiu [ Upstream commit 3d6f83df8ff2d5de84b50377e4f0d45e25311c7a ] Shifting 1 << 31 on a 32-bit int causes signed integer overflow, which leads to undefined behavior. To prevent this, cast 1 to u32 before performing the shift, ensuring well-defined behavior. This change explicitly avoids any potential overflow by ensuring that the shift occurs on an unsigned 32-bit integer. Signed-off-by: Kuan-Wei Chiu Acked-by: Petr Mladek Link: https://lore.kernel.org/r/20240928113608.1438087-1-visitorckw@gmail.com Signed-off-by: Petr Mladek Signed-off-by: Sasha Levin --- kernel/printk/printk.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index f446a06b4da8c..07668433644b8 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -523,7 +523,7 @@ static struct latched_seq clear_seq = { /* record buffer */ #define LOG_ALIGN __alignof__(unsigned long) #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT) -#define LOG_BUF_LEN_MAX (u32)(1 << 31) +#define LOG_BUF_LEN_MAX ((u32)1 << 31) static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN); static char *log_buf = __log_buf; static u32 log_buf_len = __LOG_BUF_LEN; -- 2.39.5