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 039C4185924; Fri, 15 Nov 2024 06:54:35 +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=1731653675; cv=none; b=qC+tXkzCBuYIzDekx8jWCANB3Zc1VcXkrViH8T3a9E9j+cAx92KvJKYBbDgChj00MiASxJb+78+3urKABarXWlEyMLGk/pimUEATDQXpi8RRi0hZ8u8l95VC7LaxNgPSHp697EkvYIqGgZ63mDfddQK2YTaKm1MIfhPg5VCLhTI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731653675; c=relaxed/simple; bh=4AmwZWPeyAmPepwUeBC3RvHfmewhmHBogXNySoOPFT0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=EVPsd9jAEf3Slw1VhdzNp/UqpdFYuOYVh9ZQTtZ/TMKWdee2F+lhogBWbzFhmQfYO8IT9T4qOGAr4ivBJttZKHqpJ27p8HA5fZzFRGUrCLx6BfYyYPBwv2M9fQJlxdXq+UZbd7RPIVhZNIpV81XYXkMSpFEjD4hidwUU+SQ2vJk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=aiggZYJV; 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="aiggZYJV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6171DC4CECF; Fri, 15 Nov 2024 06:54:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1731653674; bh=4AmwZWPeyAmPepwUeBC3RvHfmewhmHBogXNySoOPFT0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aiggZYJVWaFRoUF9euP367YWgeF/iMb7pahvMQvwpgfifDRjpMMP/uWEp/L7WwcFP 1sSiQ7iN4rPvGJv9/3YdhJMaBKzGLqYoMQBtLldgKFxWr6TdjkD687Ibxs2CEk/vfT 9/mH4ywgn+NLZLiTv3k0qaaVIMvdgmaF8PNOPNR0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Xiaxi Shen , Theodore Tso , stable@kernel.org, Xiangyu Chen , syzbot+59e0101c430934bc9a36@syzkaller.appspotmail.com Subject: [PATCH 6.1 34/39] ext4: fix timer use-after-free on failed mount Date: Fri, 15 Nov 2024 07:38:44 +0100 Message-ID: <20241115063723.838050061@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241115063722.599985562@linuxfoundation.org> References: <20241115063722.599985562@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xiaxi Shen commit 0ce160c5bdb67081a62293028dc85758a8efb22a upstream. Syzbot has found an ODEBUG bug in ext4_fill_super The del_timer_sync function cancels the s_err_report timer, which reminds about filesystem errors daily. We should guarantee the timer is no longer active before kfree(sbi). When filesystem mounting fails, the flow goes to failed_mount3, where an error occurs when ext4_stop_mmpd is called, causing a read I/O failure. This triggers the ext4_handle_error function that ultimately re-arms the timer, leaving the s_err_report timer active before kfree(sbi) is called. Fix the issue by canceling the s_err_report timer after calling ext4_stop_mmpd. Signed-off-by: Xiaxi Shen Reported-and-tested-by: syzbot+59e0101c430934bc9a36@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=59e0101c430934bc9a36 Link: https://patch.msgid.link/20240715043336.98097-1-shenxiaxi26@gmail.com Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: Xiangyu Chen Signed-off-by: Greg Kroah-Hartman --- fs/ext4/super.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -5617,8 +5617,8 @@ failed_mount3a: failed_mount3: /* flush s_error_work before sbi destroy */ flush_work(&sbi->s_error_work); - del_timer_sync(&sbi->s_err_report); ext4_stop_mmpd(sbi); + del_timer_sync(&sbi->s_err_report); ext4_group_desc_free(sbi); failed_mount: if (sbi->s_chksum_driver)