linux-kernel - Forwarded: [PATCH] Subject: [PATCH] ext4: skip inode expansion on readonly filesystems

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Message-ID: <68d23a22.a70a0220.1b52b.0051.GAE@google.com>
Date: Mon, 22 Sep 2025 23:11:46 -0700
From: syzbot <syzbot+4c9d23743a2409b80293@...kaller.appspotmail.com>
To: linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: Forwarded: [PATCH] Subject: [PATCH] ext4: skip inode expansion on
 readonly filesystems

For archival purposes, forwarding an incoming command email to
linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com.

***

Subject: [PATCH] Subject: [PATCH] ext4: skip inode expansion on readonly filesystems
Author: kartikey406@...il.com

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master


Fix WARNING in ext4_xattr_block_set() during orphan cleanup on readonly
filesystems when debug_want_extra_isize mount option is used.
The issue occurs when ext4_try_to_expand_extra_isize() attempts to modify
inodes on readonly filesystems during orphan cleanup, leading to warnings
when encountering invalid xattr entries. Add a readonly check to skip
expansion in this case.

Reported-by: syzbot+4c9d23743a2409b80293@...kaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?extid=4c9d23743a2409b80293
Signed-off-by: Deepanshu Kartikey <kartikey406@...il.com>
---
 fs/ext4/inode.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 5b7a15db4953..67300baa8e4e 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -6345,6 +6345,15 @@ static int __ext4_expand_extra_isize(struct inode *inode,
 	unsigned int inode_size = EXT4_INODE_SIZE(inode->i_sb);
 	struct ext4_inode_info *ei = EXT4_I(inode);
 	int error;
+	if (sb_rdonly(inode->i_sb)) {
+	    printk(KERN_ERR "ext4: READONLY CHECK TRIGGERED - skipping expansion\n");
+	return 0;
+	}
+
+	if (IS_RDONLY(inode)) {
+	     printk(KERN_ERR "ext4: READONLY CHECK TRIGGERED IS_RDONLY - skipping expansion\n");
+	return 0;
+	}
 
 	/* this was checked at iget time, but double check for good measure */
 	if ((EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize > inode_size) ||
-- 
2.43.0