ext4: add lockdep annotations for i_data_sem for ea_inode's

commit aff3bea upstream. Treat i_data_sem for ea_inodes as being in their own lockdep class to avoid lockdep complaints about ext4_setattr's use of inode_lock() on normal inodes potentially causing lock ordering with i_data_sem on ea_inodes in ext4_xattr_inode_write(). However, ea_inodes will be operated on by ext4_setattr(), so this isn't a problem. Cc: stable@kernel.org Link: https://syzkaller.appspot.com/bug?extid=298c5d8fb4a128bc27b0 Reported-by: syzbot+298c5d8fb4a128bc27b0@syzkaller.appspotmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu> Link: https://lore.kernel.org/r/20230524034951.779531-5-tytso@mit.edu Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
xanmod · Jun 9, 2023 · ef8aeff · ef8aeff
1 parent 140aa33
commit ef8aeff
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diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
@@ -1007,11 +1007,13 @@ do {									       \
  *			  where the second inode has larger inode number
  *			  than the first
  *  I_DATA_SEM_QUOTA  - Used for quota inodes only
+ *  I_DATA_SEM_EA     - Used for ea_inodes only
  */
 enum {
 	I_DATA_SEM_NORMAL = 0,
 	I_DATA_SEM_OTHER,
 	I_DATA_SEM_QUOTA,
+	I_DATA_SEM_EA
 };
 
 

diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
@@ -123,7 +123,11 @@ ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array,
 #ifdef CONFIG_LOCKDEP
 void ext4_xattr_inode_set_class(struct inode *ea_inode)
 {
+	struct ext4_inode_info *ei = EXT4_I(ea_inode);
+
 	lockdep_set_subclass(&ea_inode->i_rwsem, 1);
+	(void) ei;	/* shut up clang warning if !CONFIG_LOCKDEP */
+	lockdep_set_subclass(&ei->i_data_sem, I_DATA_SEM_EA);
 }
 #endif