From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 79F121D9A66; Sat, 12 Sep 2026 14:33:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789223639; cv=none; b=D1oEf8BuAWGokLMw5W5KYs2I9OpjUKzTkaQ1+HDsvO0FNmsc1Aw9YeknIAfF5AY66eubiI0Va1PgKjMtqM94O26gHt3KiaD+atMd9g+n4uTUAxsIdscVVevpDzzrH3mcJfd2KwbaexOpYy7wKixizGZOTBDgNCrqpNdRHzw2sxg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789223639; c=relaxed/simple; bh=4DN0Q4eA0zRpms3WEgS8FBXVlfoJeqqkx2uVm6MCPVg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qZg/4h2hiamKQgFmKhXaCulroWNOiwsMUb9hMBDA8jZyIxfByBABn9neHCbd/xddyDBZpfpG+GRvdWCxWeE3O6WUjefSDkjQxbRXSPHaqHekYZDhQfzKuZUSD1nonugaexySgUaOZzabjwYIRtuWZEDzncscMzikDHsV02HH8Yg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=2lTPGAY1; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="2lTPGAY1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3489E1F000FF; Sat, 12 Sep 2026 14:33:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789223638; bh=D1gN7I49dpbxpyB+f54n9qixG86On7XOTuuR4LvtZfo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=2lTPGAY10Y/XJOQ8xUoGTOHEFTu4RjPIN7fi0qi5wKj0VqCkIYaKtmPYlIAS38fdn t973pS6R7zZCuE9KOSWi8uy+yNnoQyTb1i2aSLLYc0uqJ0PauT3SX7s+qnIJ6jbcBR /XrIlEQZ6SD89Nt8XSV0S0ZkqleP5YYVm3P4TcwM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+5d19358d7eb30ffb0cc5@syzkaller.appspotmail.com, Yun Zhou , Jan Kara , Theodore Tso , Sasha Levin Subject: [PATCH 6.6 0831/1424] ext4: skip extra isize expansion during mount to prevent deadlock Date: Sat, 12 Sep 2026 08:54:23 +0200 Message-ID: <20260912065625.916735024@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065607.279695368@linuxfoundation.org> References: <20260912065607.279695368@linuxfoundation.org> User-Agent: quilt/0.69 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 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yun Zhou [ Upstream commit 7461c60b9c6a839b13ad4c3490681a0cf5aa0637 ] ext4_try_to_expand_extra_isize() is called from __ext4_mark_inode_dirty() while holding an active jbd2 handle. During mount (!SB_ACTIVE), the expand path may move xattrs to external blocks and release ea_inodes via iput(). When !SB_ACTIVE, iput() calls write_inode_now() which acquires s_writepages_rwsem, creating a circular lock dependency: s_writepages_rwsem --> jbd2_handle --> xattr_sem --> s_writepages_rwsem This can be triggered via: ext4_process_orphan() -> ext4_truncate() -> ext4_mark_inode_dirty() -> ext4_try_to_expand_extra_isize() or: ext4_evict_inode() -> ext4_mark_inode_dirty() -> ext4_try_to_expand_extra_isize() Skip expansion when !SB_ACTIVE. This is a minor loss of functionality (extra isize won't grow for these inodes during mount), which e2fsck can resolve later if needed. Reported-by: syzbot+5d19358d7eb30ffb0cc5@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=5d19358d7eb30ffb0cc5 Fixes: c8585c6fcaf2 ("ext4: fix races between changing inode journal mode and ext4_writepages") Signed-off-by: Yun Zhou Reviewed-by: Jan Kara Link: https://patch.msgid.link/20260623061903.2148767-1-yun.zhou@windriver.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin --- fs/ext4/inode.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 6a0afec3542bb..78b520557ab46 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -6015,6 +6015,16 @@ static int ext4_try_to_expand_extra_isize(struct inode *inode, if (ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND)) return -EOVERFLOW; + /* + * Skip expansion during mount (!SB_ACTIVE). Expanding extra isize + * may move xattrs to external blocks and release ea_inodes via iput. + * When !SB_ACTIVE, iput triggers write_inode_now() which acquires + * s_writepages_rwsem, causing a deadlock with the caller's active + * jbd2 handle (lock order: s_writepages_rwsem -> jbd2_handle). + */ + if (unlikely(!(inode->i_sb->s_flags & SB_ACTIVE))) + return -EBUSY; + /* * In nojournal mode, we can immediately attempt to expand * the inode. When journaled, we first need to obtain extra -- 2.53.0