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 E9344479899; Sat, 12 Sep 2026 12:24:22 +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=1789215864; cv=none; b=KorFFVHtT4jJfMemE4MN3+neOCNF1LpQNfB79CRzuX4r2bTwN/rjxFYTSbwf7JdmkJ9BzgHUUVtBupab9bJHo0TvwEJefHok6gRGz+y7I3tPZqAWMmxPNn7CbnwS/v8CqtbNR6xZZn5ZN/q0Na9KA5y3JBQWshA6QK9L9RO86/0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789215864; c=relaxed/simple; bh=58zbfECBdXaHBOJJviu/bcb7sHukTNMDdKWpVWwlug0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=U9sJyCteyACh+LMb/PJrm2KS/t9pAr/RNMmk3csXH8bTJfiO3jiLthndqPsgMWjWHaVPmtaLUuXY8pJJ6gvTOPWh+2b6+AtSselFisNMkjHVcI8D0VWhKz31KcEOdhkQcOm8JyVXO911FY6UP0uLxtL8QQi5tihBZFRonf0kymQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ehktIlhh; 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="ehktIlhh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E4C181F000FF; Sat, 12 Sep 2026 12:24:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789215862; bh=kC997AM/TtCCb2Ft4zz0iETUsSi6Krpt9qRztmzqu6w=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ehktIlhh8/lz8dWPfuXHCbomH3K7wItLZ632CpPNYUCUjyn2sKpkpi2UZSGyB2Yly O5s6/dl79npyy8DOIyXzRski9GlgP+V7Inw6FrFNE49h1f6CEnx8RpFM8M7v0VB1uk vZa4BMnmiV2ui8ufAZEc0Zd3778d+lLzTMFymBWI= 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 6.12 0620/1376] ext4: skip extra isize expansion during mount to prevent deadlock Date: Sat, 12 Sep 2026 08:50:46 +0200 Message-ID: <20260912065621.361574321@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065607.535295758@linuxfoundation.org> References: <20260912065607.535295758@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 6.12-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 de8ad1f90af13..b299c0a5f2ec2 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -5975,6 +5975,16 @@ 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