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 81A4B2D8382; Sat, 12 Sep 2026 07:48:38 +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=1789199319; cv=none; b=q6fApL/Jeqsf0Ybs99RkeEgrRFGvYsGOwhzLzTL2vMMOJrTKLB3+AYGtDXXwyXI4M3sIVJImHWFfowN7NpFyiOOvOhI/MSLW9WbTekfwxcHm5tXwxw54Ct9FRyC1Eo6Mfl2+sZtZYMenlyGsvkk8yz1Rewoo9iRF9Tk820MGaCg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789199319; c=relaxed/simple; bh=Zxiu7gt4xc3N1Dq78uq2ZlNhnlamzbEpmzDBYhvj1Eg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kfCzZzviGlXimVMPq67K9Qv44bmbc6NyTl3kzJkMz92JTJoEzrdBeeiaBj0dy6rbB6EZsQS4h8wz1PfPGLdLkv4p5F5f6uM1OVcIFunckoCBl6OY3ClipUufCCf2NdcSalG9wwkNECjT00gydBwp7AO34vf4ZsMsfnMgJbV4uDQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=y8mxmkaa; 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="y8mxmkaa" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 440821F000FF; Sat, 12 Sep 2026 07:48:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789199318; bh=DvTiZlNvHpExX/UzSQURBbrWADFdzkLvFbWO6/wQrlk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=y8mxmkaadV0tPSVjlaiHhhC4Y9NPW6wrR6JW8A4wOTVeOOua5FDtITjgG1CzQ8emi TwejQ1Z94nOsT74NfVLRf7ZjxZXj/7vX25meNTfvv/HPcFDw4dCKbkzFZ+DRbtkVSY ys8GT20gRLCBLErwCEpOPP4g1tqz1gzNZPSy/TU8= 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 7.2 0561/1815] ext4: skip extra isize expansion during mount to prevent deadlock Date: Sat, 12 Sep 2026 08:38:31 +0200 Message-ID: <20260912065702.053432353@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065648.999753832@linuxfoundation.org> References: <20260912065648.999753832@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 7.2-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 ed39c71504bf4..ad25b85b98366 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -6511,6 +6511,16 @@ 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