linux-kernel - Forwarded: Re: [syzbot] [ext4?] WARNING in ext4_xattr_inode_update

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Message-ID: <6908669d.050a0220.29fc44.0037.GAE@google.com>
Date: Mon, 03 Nov 2025 00:23:57 -0800
From: syzbot <syzbot+76916a45d2294b551fd9@...kaller.appspotmail.com>
To: linux-kernel@...r.kernel.org
Subject: Forwarded: Re: [syzbot] [ext4?] WARNING in ext4_xattr_inode_update_ref
 (2)

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Subject: Re: [syzbot] [ext4?] WARNING in ext4_xattr_inode_update_ref (2)
Author: lizhi.xu@...driver.com

#syz test

diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index ce7253b3f549..5f535d45111b 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -1040,6 +1040,13 @@ static int ext4_xattr_inode_update_ref(handle_t *handle, struct inode *ea_inode,
 		ret = -EFSCORRUPTED;
 		goto out;
 	}
+	if (overflows_type(ref_count + ref_change, u64)) {
+		ext4_error_inode(ea_inode, __func__, __LINE__, 0,
+			"EA inode %lu ref overflows: ref_count=%lld ref_change=%d",
+			ea_inode->i_ino, ref_count, ref_change);
+		ret = -EFSCORRUPTED;
+		goto out;
+	}
 	ref_count += ref_change;
 	ext4_xattr_inode_set_ref(ea_inode, ref_count);