EXT4-fs (loop9): mounted filesystem without journal. Opts: barrier=0x0000000000000006,resuid=0x0000000000000000,barrier=0x0000000000000003,norecovery,block_validity,data_err=abort,,errors=continue. Quota mode: none.
xt_bpf: check failed: parse error
netlink: 24 bytes leftover after parsing attributes in process `syz.9.310'.
netlink: 24 bytes leftover after parsing attributes in process `syz.9.310'.
==================================================================
BUG: KASAN: use-after-free in dx_move_dirents fs/ext4/namei.c:1935 [inline]
BUG: KASAN: use-after-free in do_split+0x132f/0x1fb0 fs/ext4/namei.c:2056
Write of size 24923 at addr ffff88812676bc2a by task syz.9.310/1413

CPU: 0 PID: 1413 Comm: syz.9.310 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:88
 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
 print_address_description+0x7f/0x2c0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:427 [inline]
 kasan_report+0xf1/0x140 mm/kasan/report.c:444
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x249/0x2a0 mm/kasan/generic.c:189
 memset+0x23/0x40 mm/kasan/shadow.c:44
 dx_move_dirents fs/ext4/namei.c:1935 [inline]
 do_split+0x132f/0x1fb0 fs/ext4/namei.c:2056
 ext4_dx_add_entry+0x54f/0x1620 fs/ext4/namei.c:2688
 ext4_add_entry+0xa9c/0x1030 fs/ext4/namei.c:2468
 ext4_add_nondir+0x97/0x270 fs/ext4/namei.c:2845
 ext4_create+0x2e6/0x470 fs/ext4/namei.c:2891
 vfs_create+0x342/0x520 fs/namei.c:3170
 do_mknodat+0x334/0x7a0 fs/namei.c:4002
 __do_sys_mknod fs/namei.c:4035 [inline]
 __se_sys_mknod fs/namei.c:4033 [inline]
 __x64_sys_mknod+0x8e/0xa0 fs/namei.c:4033
 x64_sys_call+0x886/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:134
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fe61a937819
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe619392028 EFLAGS: 00000246 ORIG_RAX: 0000000000000085
RAX: ffffffffffffffda RBX: 00007fe61abb0fa0 RCX: 00007fe61a937819
RDX: 0000000000000247 RSI: 0000000000000010 RDI: 0000200000000340
RBP: 00007fe61a9cdc91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe61abb1038 R14: 00007fe61abb0fa0 R15: 00007ffccf9d6198
 </TASK>

The buggy address belongs to the page:
page:ffffea000499dac0 refcount:2 mapcount:0 mapping:ffff8881093062d8 index:0x8 pfn:0x12676b
memcg:ffff888100250000
aops:def_blk_aops ino:700009
flags: 0x400000000002203e(referenced|uptodate|dirty|lru|active|private|mappedtodisk|zone=1)
raw: 400000000002203e ffffea00049d55c8 ffffea000499db48 ffff8881093062d8
raw: 0000000000000008 ffff888111eaaa80 00000002ffffffff ffff888100250000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x112c40(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_HARDWALL), pid 1093, ts 70770517142, free_ts 70744540902
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x192/0x1b0 mm/page_alloc.c:2605
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2611
 get_page_from_freelist+0x2d3a/0x2dc0 mm/page_alloc.c:4485
 __alloc_pages+0x1a2/0x460 mm/page_alloc.c:5822
 __alloc_pages_node include/linux/gfp.h:595 [inline]
 alloc_pages_node include/linux/gfp.h:609 [inline]
 alloc_pages include/linux/gfp.h:622 [inline]
 __page_cache_alloc include/linux/pagemap.h:305 [inline]
 page_cache_ra_unbounded+0x2d5/0x9a0 mm/readahead.c:227
 do_page_cache_ra mm/readahead.c:280 [inline]
 force_page_cache_ra+0x3fd/0x460 mm/readahead.c:312
 page_cache_sync_ra+0x2b4/0x430 mm/readahead.c:590
 page_cache_sync_readahead include/linux/pagemap.h:831 [inline]
 filemap_get_pages mm/filemap.c:2569 [inline]
 filemap_read+0x694/0x2040 mm/filemap.c:2654
 generic_file_read_iter+0xac/0x400 mm/filemap.c:2814
 blkdev_read_iter+0x12f/0x160 block/fops.c:563
 call_read_iter include/linux/fs.h:2206 [inline]
 new_sync_read fs/read_write.c:404 [inline]
 vfs_read+0x6c9/0xc40 fs/read_write.c:485
 ksys_read+0x149/0x250 fs/read_write.c:623
 __do_sys_read fs/read_write.c:633 [inline]
 __se_sys_read fs/read_write.c:631 [inline]
 __x64_sys_read+0x7b/0x90 fs/read_write.c:631
 x64_sys_call+0x96d/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:1
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1472 [inline]
 free_pcp_prepare mm/page_alloc.c:1544 [inline]
 free_unref_page_prepare+0x542/0x550 mm/page_alloc.c:3534
 free_unref_page+0xae/0x540 mm/page_alloc.c:3616
 free_the_page mm/page_alloc.c:805 [inline]
 __free_pages+0x6c/0x100 mm/page_alloc.c:5898
 __free_slab+0xe8/0x1e0 mm/slub.c:2025
 free_slab mm/slub.c:2040 [inline]
 discard_slab+0x29/0x40 mm/slub.c:2046
 __slab_free+0x211/0x290 mm/slub.c:3431
 do_slab_free mm/slub.c:3514 [inline]
 ___cache_free+0x104/0x120 mm/slub.c:3535
 qlink_free+0x4d/0x90 mm/kasan/quarantine.c:157
 qlist_free_all+0x5f/0xb0 mm/kasan/quarantine.c:176
 kasan_quarantine_reduce+0x14a/0x170 mm/kasan/quarantine.c:283
 __kasan_slab_alloc+0x2f/0xf0 mm/kasan/common.c:443
 kasan_slab_alloc include/linux/kasan.h:217 [inline]
 slab_post_alloc_hook+0x4f/0x2b0 mm/slab.h:550
 slab_alloc_node mm/slub.c:3245 [inline]
 slab_alloc mm/slub.c:3255 [inline]
 kmem_cache_alloc+0xf7/0x260 mm/slub.c:3260
 getname_flags+0xb9/0x500 fs/namei.c:138
 user_path_at_empty+0x30/0x1c0 fs/namei.c:2890
 user_path_at include/linux/namei.h:57 [inline]
 vfs_statx+0x109/0xa20 fs/stat.c:221

Memory state around the buggy address:
 ffff88812676bf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88812676bf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88812676c000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff88812676c080: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
 ffff88812676c100: fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb fb
==================================================================