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 940901494C9; Thu, 13 Jun 2024 12:04:30 +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=1718280270; cv=none; b=ixz1hryTwk4EWK1ZzTCk2KN+Ex4JlBH3t88bI6mekwLIPmYaKqklZ549/7gk8atcEupUr5Wju5oxSkOqeXWZI5tc5e8KvCM7fCEKq8JOTr1VwaTFtem7Ti3VL5MmnH6vPmS+pLGubfQ1QxvzyvBgqdB4drlLn6BnxF/ap81aPyw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718280270; c=relaxed/simple; bh=hgr60hx0oQ6G6pcLmUaJCCUGhArtJiHJmz3xStf5kvw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=IZcojMfjKnFMGREuKobnMUGbz8EyCTChZjJ2mXAEJW/YuzLIIAhM9tCz0+DxDCZe6ouhn7qTL9aa4UqGYLKsYVTDU3yG9Ik01bq54jIYwg7g+5P1X2XC7FoUki3C0UMonyNnGHqov9C41SDFPaMMTHz+hyl+Ei6++kmjnm+ulEQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=aFGrS3bo; 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="aFGrS3bo" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9BE00C2BBFC; Thu, 13 Jun 2024 12:04:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1718280270; bh=hgr60hx0oQ6G6pcLmUaJCCUGhArtJiHJmz3xStf5kvw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aFGrS3bomoYZkHwb86jX7k6x6SqmeP4GijxFd0N70/FiWShI7LuZoXFRy9h1AyNnJ LQaLEdW3wiIeBfEKnhaxZGk15ySdpo2vEaWGUSvH58P8hKw4NrhVja86wg9VZ7eF51 biqEidigjZVLzOFjIMaxBEILw4V5mP2m2cheW9+w= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+dd43bd0f7474512edc47@syzkaller.appspotmail.com, stable@kernel.org, Baokun Li , Jan Kara , Theodore Tso Subject: [PATCH 5.4 200/202] ext4: fix mb_cache_entrys e_refcnt leak in ext4_xattr_block_cache_find() Date: Thu, 13 Jun 2024 13:34:58 +0200 Message-ID: <20240613113235.456655046@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240613113227.759341286@linuxfoundation.org> References: <20240613113227.759341286@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 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Baokun Li commit 0c0b4a49d3e7f49690a6827a41faeffad5df7e21 upstream. Syzbot reports a warning as follows: ============================================ WARNING: CPU: 0 PID: 5075 at fs/mbcache.c:419 mb_cache_destroy+0x224/0x290 Modules linked in: CPU: 0 PID: 5075 Comm: syz-executor199 Not tainted 6.9.0-rc6-gb947cc5bf6d7 RIP: 0010:mb_cache_destroy+0x224/0x290 fs/mbcache.c:419 Call Trace: ext4_put_super+0x6d4/0xcd0 fs/ext4/super.c:1375 generic_shutdown_super+0x136/0x2d0 fs/super.c:641 kill_block_super+0x44/0x90 fs/super.c:1675 ext4_kill_sb+0x68/0xa0 fs/ext4/super.c:7327 [...] ============================================ This is because when finding an entry in ext4_xattr_block_cache_find(), if ext4_sb_bread() returns -ENOMEM, the ce's e_refcnt, which has already grown in the __entry_find(), won't be put away, and eventually trigger the above issue in mb_cache_destroy() due to reference count leakage. So call mb_cache_entry_put() on the -ENOMEM error branch as a quick fix. Reported-by: syzbot+dd43bd0f7474512edc47@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=dd43bd0f7474512edc47 Fixes: fb265c9cb49e ("ext4: add ext4_sb_bread() to disambiguate ENOMEM cases") Cc: stable@kernel.org Signed-off-by: Baokun Li Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20240504075526.2254349-2-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/ext4/xattr.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -3079,8 +3079,10 @@ ext4_xattr_block_cache_find(struct inode bh = ext4_sb_bread(inode->i_sb, ce->e_value, REQ_PRIO); if (IS_ERR(bh)) { - if (PTR_ERR(bh) == -ENOMEM) + if (PTR_ERR(bh) == -ENOMEM) { + mb_cache_entry_put(ea_block_cache, ce); return NULL; + } bh = NULL; EXT4_ERROR_INODE(inode, "block %lu read error", (unsigned long)ce->e_value);