linux-ext4 - [PATCH 2/4] ext4: set lockdep subclass for the ea_inode in ext4_xattr_inode_cache

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Message-Id: <20230524034951.779531-3-tytso@mit.edu>
Date:   Tue, 23 May 2023 23:49:49 -0400
From:   "Theodore Ts'o" <tytso@....edu>
To:     Ext4 Developers List <linux-ext4@...r.kernel.org>
Cc:     "Theodore Ts'o" <tytso@....edu>, stable@...nel.org,
        syzbot+d4b971e744b1f5439336@...kaller.appspotmail.com
Subject: [PATCH 2/4] ext4: set lockdep subclass for the ea_inode in ext4_xattr_inode_cache_find()

If the ea_inode has been pushed out of the inode cache while there is
still a reference in the mb_cache, the lockdep subclass will not be
set on the inode, which can lead to some lockdep false positives.

Fixes: 33d201e0277b ("xt4: fix lockdep warning about recursive inode locking")
Cc: stable@...nel.org
Reported-by: syzbot+d4b971e744b1f5439336@...kaller.appspotmail.com
Signed-off-by: Theodore Ts'o <tytso@....edu>
---
 fs/ext4/xattr.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index a27208129a80..ff7ab63c5b4f 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -1539,6 +1539,7 @@ ext4_xattr_inode_cache_find(struct inode *inode, const void *value,
 				     EXT4_IGET_EA_INODE);
 		if (IS_ERR(ea_inode))
 			goto next_entry;
+		ext4_xattr_inode_set_class(ea_inode);
 		if (i_size_read(ea_inode) == value_len &&
 		    !ext4_xattr_inode_read(ea_inode, ea_data, value_len) &&
 		    !ext4_xattr_inode_verify_hashes(ea_inode, NULL, ea_data,
-- 
2.31.0