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 562BC13AA2A for ; Fri, 5 Jul 2024 06:56:03 +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=1720162563; cv=none; b=fJq+9erBiF6xdp5Zee6VRG7J/7Vzlt2ZMgxXApTO36AQkJozok6sVZ6O7nn2DTJG/kfOHPBxHHZ3zg9Qic1e0eRxV+baEBREc20gZQY9yGEyk90kdTT2DchcfE5OOLR6VuaQknPRLMj3EXemZrZxisqHWcSxXso9wshiazn9XR8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720162563; c=relaxed/simple; bh=yHjKpdci7bIH/UxUCJI+boPy601IA4ogzNi3Pk3prbw=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=rDER2h2AWycHVK0P6nfcOK2XUGazyr3H5QoWPmRTxeIO1JcarEmP7pfovcoLPad4v/WbxL5crCuA5yVcQIb3pS7TDHdwlafzNwt6fNSW57rSnOjNUNtclLDV2e5LW8Q+ytlfRRAo8E0s2qXjV0ufVpcAGlauKaOdKfpAcsoa//E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=x88lb0Ry; 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="x88lb0Ry" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D1A8FC116B1; Fri, 5 Jul 2024 06:56:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1720162563; bh=yHjKpdci7bIH/UxUCJI+boPy601IA4ogzNi3Pk3prbw=; h=From:To:Cc:Subject:Date:Reply-to:From; b=x88lb0RyQzP1CPsAx4L0XKVyoVtPOyPWALc7tz6cqA/+A94AAOLYL7B57BArj/iMZ sAGdaz7yMQ4fDE3aAQSCmhfXfHif5YL+J/1EY6jyHdzkJug6LhAIsK9eiHIKMPtom4 TzKRlZS/V1f8lJbZcNltT2AWdc0felxNHybDSbnU= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2024-39476: md/raid5: fix deadlock that raid5d() wait for itself to clear MD_SB_CHANGE_PENDING Date: Fri, 5 Jul 2024 08:55:20 +0200 Message-ID: <2024070518-CVE-2024-39476-aa2d@gregkh> X-Mailer: git-send-email 2.45.2 Precedence: bulk X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Reply-to: , X-Developer-Signature: v=1; a=openpgp-sha256; l=4365; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=yHjKpdci7bIH/UxUCJI+boPy601IA4ogzNi3Pk3prbw=; b=owGbwMvMwCRo6H6F97bub03G02pJDGntM64dWukkuND3kHZoGqP7jtzCSwHHkiexNk34slv4T fURx5kfO2JZGASZGGTFFFm+bOM5ur/ikKKXoe1pmDmsTCBDGLg4BWAiLLsYFqzXYXSqzo4Wib9m 8KE44H7gJPmFJgzzlI/falv//i77nBlOZ5o+37tRs9bjLQA= X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit Description =========== In the Linux kernel, the following vulnerability has been resolved: md/raid5: fix deadlock that raid5d() wait for itself to clear MD_SB_CHANGE_PENDING Xiao reported that lvm2 test lvconvert-raid-takeover.sh can hang with small possibility, the root cause is exactly the same as commit bed9e27baf52 ("Revert "md/raid5: Wait for MD_SB_CHANGE_PENDING in raid5d"") However, Dan reported another hang after that, and junxiao investigated the problem and found out that this is caused by plugged bio can't issue from raid5d(). Current implementation in raid5d() has a weird dependence: 1) md_check_recovery() from raid5d() must hold 'reconfig_mutex' to clear MD_SB_CHANGE_PENDING; 2) raid5d() handles IO in a deadloop, until all IO are issued; 3) IO from raid5d() must wait for MD_SB_CHANGE_PENDING to be cleared; This behaviour is introduce before v2.6, and for consequence, if other context hold 'reconfig_mutex', and md_check_recovery() can't update super_block, then raid5d() will waste one cpu 100% by the deadloop, until 'reconfig_mutex' is released. Refer to the implementation from raid1 and raid10, fix this problem by skipping issue IO if MD_SB_CHANGE_PENDING is still set after md_check_recovery(), daemon thread will be woken up when 'reconfig_mutex' is released. Meanwhile, the hang problem will be fixed as well. The Linux kernel CVE team has assigned CVE-2024-39476 to this issue. Affected and fixed versions =========================== Issue introduced in 4.19.262 with commit f3d55bd5b7b9 and fixed in 4.19.316 with commit b32aa95843ca Issue introduced in 5.4.220 with commit 1c00bb624cd0 and fixed in 5.4.278 with commit 634ba3c97ec4 Issue introduced in 5.10.150 with commit 782b3e71c957 and fixed in 5.10.219 with commit aa64464c8f4d Issue introduced in 5.15.75 with commit 9e86dffd0b02 and fixed in 5.15.161 with commit 098d54934814 Issue introduced in 6.1 with commit 5e2cf333b7bd and fixed in 6.1.94 with commit 3f8d5e802d4c Issue introduced in 6.1 with commit 5e2cf333b7bd and fixed in 6.6.34 with commit cd2538e5af49 Issue introduced in 6.1 with commit 5e2cf333b7bd and fixed in 6.9.5 with commit e332a12f65d8 Issue introduced in 6.1 with commit 5e2cf333b7bd and fixed in 6.10-rc1 with commit 151f66bb618d Issue introduced in 4.14.296 with commit 7d808fe6af84 Issue introduced in 4.19.307 with commit 1e8c1c2a9269 Issue introduced in 5.4.269 with commit 7f71d9817cea Issue introduced in 5.10.210 with commit 88ec9bbcd33c Issue introduced in 5.15.148 with commit 0ee3ded745ca Issue introduced in 5.19.17 with commit 2cab058f2b14 Issue introduced in 6.0.3 with commit 91962e40ec3d Issue introduced in 6.1.74 with commit bed0acf330b2 Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2024-39476 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: drivers/md/raid5.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: https://git.kernel.org/stable/c/b32aa95843cac6b12c2c014d40fca18aef24a347 https://git.kernel.org/stable/c/634ba3c97ec413cb10681c7b196db43ee461ecf4 https://git.kernel.org/stable/c/aa64464c8f4d2ab92f6d0b959a1e0767b829d787 https://git.kernel.org/stable/c/098d54934814dd876963abfe751c3b1cf7fbe56a https://git.kernel.org/stable/c/3f8d5e802d4cedd445f9a89be8c3fd2d0e99024b https://git.kernel.org/stable/c/cd2538e5af495b3c747e503db346470fc1ffc447 https://git.kernel.org/stable/c/e332a12f65d8fed8cf63bedb4e9317bb872b9ac7 https://git.kernel.org/stable/c/151f66bb618d1fd0eeb84acb61b4a9fa5d8bb0fa