Re: [syzbot] [ext4?] INFO: task hung in filename_rmdir

From: Edward Adam Davis

Date: Sun Mar 01 2026 - 03:35:40 EST


#syz test

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 293f698b7042..4b72da4d646f 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2425,6 +2425,8 @@ struct ext4_dir_entry_2 {
char name[EXT4_NAME_LEN]; /* File name */
};

+#define DIFF_AREA_DE_XH sizeof(struct ext4_dir_entry_2)
+
/*
* Access the hashes at the end of ext4_dir_entry_2
*/
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 7bf9ba19a89d..313c460a93c5 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -2160,7 +2160,7 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
error = -EIO;
goto getblk_failed;
}
- memcpy(new_bh->b_data, s->base, new_bh->b_size);
+ memcpy(new_bh->b_data + DIFF_AREA_DE_XH, s->base, new_bh->b_size);
ext4_xattr_block_csum_set(inode, new_bh);
set_buffer_uptodate(new_bh);
unlock_buffer(new_bh);
diff --git a/fs/ext4/xattr.h b/fs/ext4/xattr.h
index 1fedf44d4fb6..4a28023c72e8 100644
--- a/fs/ext4/xattr.h
+++ b/fs/ext4/xattr.h
@@ -8,6 +8,7 @@
*/

#include <linux/xattr.h>
+#include "ext4.h"

/* Magic value in attribute blocks */
#define EXT4_XATTR_MAGIC 0xEA020000
@@ -90,7 +91,7 @@ struct ext4_xattr_entry {
#define EXT4_XATTR_MIN_LARGE_EA_SIZE(b) \
((b) - EXT4_XATTR_LEN(3) - sizeof(struct ext4_xattr_header) - 4)

-#define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
+#define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data + DIFF_AREA_DE_XH))
#define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
#define BFIRST(bh) ENTRY(BHDR(bh)+1)
#define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)