[syzbot ci] Re: Data in direntry (dirdata) feature

[syzbot ci <syzbot+cid7b922cb3d448114@syzkaller.appspotmail.com>]

syzbot ci has tested the following series

[v2] Data in direntry (dirdata) feature
https://lore.kernel.org/all/20260610152417.13576-1-ablagodarenko@thelustrecollective.com
* [PATCH v2 01/10] ext4: replace ext4_dir_entry with ext4_dir_entry_2
* [PATCH v2 02/10] ext4: add ext4_dir_entry_is_tail()
* [PATCH v2 03/10] ext4: refactor dx_root to support variable dirent sizes
* [PATCH v2 04/10] ext4: add dirdata format definitions and access helpers
* [PATCH v2 05/10] ext4: preserve dirdata bits in get_dtype()
* [PATCH v2 06/10] ext4: add ext4_dir_entry_len() and harden dirdata parsing
* [PATCH v2 07/10] ext4: rename ext4_dir_rec_len() and clarify dirdata usage
* [PATCH v2 08/10] ext4: dirdata feature
* [PATCH v2 09/10] ext4: add dirdata set/get helpers
* [PATCH v2 10/10] ext4: Add EXT4_IOC_SET_LUFID ioctl for setting LUFID on directory entries

and found the following issues:
* KASAN: slab-out-of-bounds Read in __ext4_check_dir_entry
* KASAN: slab-out-of-bounds Read in ext4_inlinedir_to_tree
* KASAN: slab-use-after-free Read in __ext4_check_dir_entry
* KASAN: slab-use-after-free Read in ext4_inlinedir_to_tree
* KASAN: use-after-free Read in __ext4_check_dir_entry

Full report is available here:
https://ci.syzbot.org/series/5bf0e2fa-2e68-4532-8396-4568879b2788

***

KASAN: slab-out-of-bounds Read in __ext4_check_dir_entry

tree:      torvalds
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base:      9716c086c8e8b141d35aa61f2e96a2e83de212a7
arch:      amd64
compiler:  Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
config:    https://ci.syzbot.org/builds/ddf6ee7c-dfa8-4383-b004-10140edc081c/config
syz repro: https://ci.syzbot.org/findings/b0854918-13f9-49dd-ab30-12154f0debe2/syz_repro

loop0: lost filesystem error report for type 5 error -117
EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.
==================================================================
BUG: KASAN: slab-out-of-bounds in ext4_dirent_get_data_len fs/ext4/ext4.h:4069 [inline]
BUG: KASAN: slab-out-of-bounds in ext4_dir_entry_len fs/ext4/ext4.h:4096 [inline]
BUG: KASAN: slab-out-of-bounds in __ext4_check_dir_entry+0x65a/0xc40 fs/ext4/dir.c:96
Read of size 1 at addr ffff8881022db7f5 by task syz.0.23/5815

CPU: 1 UID: 0 PID: 5815 Comm: syz.0.23 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 ext4_dirent_get_data_len fs/ext4/ext4.h:4069 [inline]
 ext4_dir_entry_len fs/ext4/ext4.h:4096 [inline]
 __ext4_check_dir_entry+0x65a/0xc40 fs/ext4/dir.c:96
 ext4_check_all_de+0x66/0x150 fs/ext4/dir.c:657
 ext4_convert_inline_data_nolock+0x1b7/0x990 fs/ext4/inline.c:1121
 ext4_try_add_inline_entry+0x604/0x8e0 fs/ext4/inline.c:1247
 __ext4_add_entry+0x390/0x1f40 fs/ext4/namei.c:2529
 ext4_add_entry fs/ext4/namei.c:2613 [inline]
 ext4_mkdir+0x5e5/0xce0 fs/ext4/namei.c:3175
 vfs_mkdir+0x413/0x630 fs/namei.c:5271
 filename_mkdirat+0x285/0x510 fs/namei.c:5304
 __do_sys_mkdirat fs/namei.c:5325 [inline]
 __se_sys_mkdirat+0x35/0x150 fs/namei.c:5322
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f669359bcc7
Code: 00 66 90 48 89 f2 b9 00 01 00 00 48 89 fe bf 9c ff ff ff e9 db f7 ff ff 66 2e 0f 1f 84 00 00 00 00 00 90 b8 02 01 00 00 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:00007ffd42381d38 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007ffd42381dc0 RCX: 00007f669359bcc7
RDX: 00000000000001ff RSI: 0000200000001200 RDI: 00000000ffffff9c
RBP: 00002000000024c0 R08: 0000200000000240 R09: 0000000000000000
R10: 00002000000024c0 R11: 0000000000000246 R12: 0000200000001200
R13: 00007ffd42381d80 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

Allocated by task 5066:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x31c/0x660 mm/slub.c:5420
 kmalloc_noprof include/linux/slab.h:950 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 kernfs_get_open_node fs/kernfs/file.c:543 [inline]
 kernfs_fop_open+0x862/0xda0 fs/kernfs/file.c:718
 do_dentry_open+0x822/0x13a0 fs/open.c:947
 vfs_open+0x3b/0x340 fs/open.c:1079
 do_open fs/namei.c:4699 [inline]
 path_openat+0x2e08/0x3860 fs/namei.c:4858
 do_file_open+0x23e/0x4a0 fs/namei.c:4887
 do_sys_openat2+0x113/0x200 fs/open.c:1364
 do_sys_open fs/open.c:1370 [inline]
 __do_sys_openat fs/open.c:1386 [inline]
 __se_sys_openat fs/open.c:1381 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1381
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Last potentially related work creation:
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
 kvfree_call_rcu+0x100/0x430 mm/slab_common.c:1970
 kernfs_unlink_open_file+0x3fe/0x4b0 fs/kernfs/file.c:604
 kernfs_fop_release+0x2eb/0x440 fs/kernfs/file.c:783
 __fput+0x44f/0xa60 fs/file_table.c:510
 fput_close_sync+0x11f/0x240 fs/file_table.c:615
 __do_sys_close fs/open.c:1507 [inline]
 __se_sys_close fs/open.c:1492 [inline]
 __x64_sys_close+0x7e/0x110 fs/open.c:1492
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff8881022db700
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 117 bytes to the right of
 allocated 128-byte region [ffff8881022db700, ffff8881022db780)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1022db
flags: 0x17ff00000000000(node=0|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 017ff00000000000 ffff888100041a00 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2000(__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 0, tgid 0 (swapper/0), ts 2408938923, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x22d/0x280 mm/page_alloc.c:1853
 prep_new_page mm/page_alloc.c:1861 [inline]
 get_page_from_freelist+0x2593/0x2610 mm/page_alloc.c:3941
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5221
 alloc_slab_page mm/slub.c:3278 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3467
 new_slab mm/slub.c:3525 [inline]
 refill_objects+0x339/0x3d0 mm/slub.c:7272
 refill_sheaf mm/slub.c:2816 [inline]
 __pcs_replace_empty_main+0x321/0x720 mm/slub.c:4652
 alloc_from_pcs mm/slub.c:4750 [inline]
 slab_alloc_node mm/slub.c:4884 [inline]
 __do_kmalloc_node mm/slub.c:5295 [inline]
 __kmalloc_noprof+0x474/0x760 mm/slub.c:5308
 kmalloc_noprof include/linux/slab.h:954 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 __alloc_empty_sheaf mm/slub.c:2768 [inline]
 alloc_empty_sheaf mm/slub.c:2783 [inline]
 __pcs_replace_empty_main+0x2df/0x720 mm/slub.c:4647
 alloc_from_pcs mm/slub.c:4750 [inline]
 slab_alloc_node mm/slub.c:4884 [inline]
 kmem_cache_alloc_noprof+0x37d/0x650 mm/slub.c:4906
 dup_fd+0x55/0xb40 fs/file.c:390
 copy_files+0xc8/0x120 kernel/fork.c:1639
 copy_process+0x1d94/0x4440 kernel/fork.c:2252
 kernel_clone+0x2d7/0x940 kernel/fork.c:2722
 user_mode_thread+0x110/0x180 kernel/fork.c:2798
 rest_init+0x23/0x300 init/main.c:727
 start_kernel+0x38a/0x3e0 init/main.c:1220
page_owner free stack trace missing

Memory state around the buggy address:
 ffff8881022db680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8881022db700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8881022db780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                                             ^
 ffff8881022db800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8881022db880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


***

KASAN: slab-out-of-bounds Read in ext4_inlinedir_to_tree

tree:      torvalds
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base:      9716c086c8e8b141d35aa61f2e96a2e83de212a7
arch:      amd64
compiler:  Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
config:    https://ci.syzbot.org/builds/ddf6ee7c-dfa8-4383-b004-10140edc081c/config
syz repro: https://ci.syzbot.org/findings/2dff870b-f382-4c93-8d8d-b2291d921224/syz_repro

loop1: lost filesystem error report for type 5 error -117
EXT4-fs (loop1): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.
==================================================================
BUG: KASAN: slab-out-of-bounds in ext4_dir_entry_len fs/ext4/ext4.h:4095 [inline]
BUG: KASAN: slab-out-of-bounds in ext4_inlinedir_to_tree+0xda5/0x10d0 fs/ext4/inline.c:1335
Read of size 2 at addr ffff888115a3183c by task syz.1.18/5839

CPU: 1 UID: 0 PID: 5839 Comm: syz.1.18 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 ext4_dir_entry_len fs/ext4/ext4.h:4095 [inline]
 ext4_inlinedir_to_tree+0xda5/0x10d0 fs/ext4/inline.c:1335
 ext4_htree_fill_tree+0x517/0x1230 fs/ext4/namei.c:1182
 ext4_dx_readdir fs/ext4/dir.c:600 [inline]
 ext4_readdir+0x2db4/0x3640 fs/ext4/dir.c:146
 iterate_dir+0x399/0x570 fs/readdir.c:110
 __do_sys_getdents64 fs/readdir.c:399 [inline]
 __se_sys_getdents64+0xf1/0x280 fs/readdir.c:384
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3e02b9ce59
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:00007f3e03ad5028 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 00007f3e02e15fa0 RCX: 00007f3e02b9ce59
RDX: 0000000000001000 RSI: 0000200000000f80 RDI: 0000000000000004
RBP: 00007f3e02c32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3e02e16038 R14: 00007f3e02e15fa0 R15: 00007ffcaa902298
 </TASK>

Allocated by task 5839:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5296 [inline]
 __kmalloc_noprof+0x35c/0x760 mm/slub.c:5308
 kmalloc_noprof include/linux/slab.h:954 [inline]
 ext4_inlinedir_to_tree+0x312/0x10d0 fs/ext4/inline.c:1292
 ext4_htree_fill_tree+0x517/0x1230 fs/ext4/namei.c:1182
 ext4_dx_readdir fs/ext4/dir.c:600 [inline]
 ext4_readdir+0x2db4/0x3640 fs/ext4/dir.c:146
 iterate_dir+0x399/0x570 fs/readdir.c:110
 __do_sys_getdents64 fs/readdir.c:399 [inline]
 __se_sys_getdents64+0xf1/0x280 fs/readdir.c:384
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888115a31800
 which belongs to the cache kmalloc-64 of size 64
The buggy address is located 0 bytes to the right of
 allocated 60-byte region [ffff888115a31800, ffff888115a3183c)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x115a31
flags: 0x17ff00000000000(node=0|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 017ff00000000000 ffff8881000418c0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800200020 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2c40(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5051, tgid 5051 (acpid), ts 27203740677, free_ts 27201732767
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x22d/0x280 mm/page_alloc.c:1853
 prep_new_page mm/page_alloc.c:1861 [inline]
 get_page_from_freelist+0x2593/0x2610 mm/page_alloc.c:3941
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5221
 alloc_slab_page mm/slub.c:3278 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3467
 new_slab mm/slub.c:3525 [inline]
 refill_objects+0x339/0x3d0 mm/slub.c:7272
 refill_sheaf mm/slub.c:2816 [inline]
 __pcs_replace_empty_main+0x321/0x720 mm/slub.c:4652
 alloc_from_pcs mm/slub.c:4750 [inline]
 slab_alloc_node mm/slub.c:4884 [inline]
 __do_kmalloc_node mm/slub.c:5295 [inline]
 __kmalloc_noprof+0x474/0x760 mm/slub.c:5308
 kmalloc_noprof include/linux/slab.h:954 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 tomoyo_get_name+0x20c/0x590 security/tomoyo/memory.c:173
 tomoyo_parse_name_union+0xd9/0x130 security/tomoyo/util.c:260
 tomoyo_update_path_acl security/tomoyo/file.c:399 [inline]
 tomoyo_write_file+0x3a6/0xc50 security/tomoyo/file.c:1027
 tomoyo_write_domain2 security/tomoyo/common.c:1160 [inline]
 tomoyo_add_entry security/tomoyo/common.c:2177 [inline]
 tomoyo_supervisor+0x1208/0x1570 security/tomoyo/common.c:2238
 tomoyo_audit_path_log security/tomoyo/file.c:169 [inline]
 tomoyo_path_permission+0x25a/0x380 security/tomoyo/file.c:592
 tomoyo_check_open_permission+0x2b2/0x470 security/tomoyo/file.c:782
 security_file_open+0xa9/0x240 security/security.c:2739
 do_dentry_open+0x4a8/0x13a0 fs/open.c:924
 vfs_open+0x3b/0x340 fs/open.c:1079
page last free pid 15 tgid 15 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1397 [inline]
 __free_frozen_pages+0xc1c/0xd30 mm/page_alloc.c:2938
 __tlb_remove_table_free mm/mmu_gather.c:228 [inline]
 tlb_remove_table_rcu+0x85/0x100 mm/mmu_gather.c:291
 rcu_do_batch kernel/rcu/tree.c:2617 [inline]
 rcu_core+0x7cd/0x1070 kernel/rcu/tree.c:2869
 handle_softirqs+0x22a/0x840 kernel/softirq.c:622
 run_ksoftirqd+0x36/0x60 kernel/softirq.c:1076
 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
 kthread+0x389/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff888115a31700: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff888115a31780: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc
>ffff888115a31800: 00 00 00 00 00 00 00 04 fc fc fc fc fc fc fc fc
                                        ^
 ffff888115a31880: 00 00 00 00 00 00 02 fc fc fc fc fc fc fc fc fc
 ffff888115a31900: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================


***

KASAN: slab-use-after-free Read in __ext4_check_dir_entry

tree:      torvalds
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base:      9716c086c8e8b141d35aa61f2e96a2e83de212a7
arch:      amd64
compiler:  Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
config:    https://ci.syzbot.org/builds/ddf6ee7c-dfa8-4383-b004-10140edc081c/config
syz repro: https://ci.syzbot.org/findings/f1d48ea1-6e87-4d64-9c13-8bf8aed109fc/syz_repro

loop0: lost filesystem error report for type 5 error -117
EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.
==================================================================
BUG: KASAN: slab-use-after-free in ext4_dirent_get_data_len fs/ext4/ext4.h:4069 [inline]
BUG: KASAN: slab-use-after-free in ext4_dir_entry_len fs/ext4/ext4.h:4096 [inline]
BUG: KASAN: slab-use-after-free in __ext4_check_dir_entry+0x65a/0xc40 fs/ext4/dir.c:96
Read of size 1 at addr ffff888114d8c045 by task syz.0.20/5821

CPU: 1 UID: 0 PID: 5821 Comm: syz.0.20 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 ext4_dirent_get_data_len fs/ext4/ext4.h:4069 [inline]
 ext4_dir_entry_len fs/ext4/ext4.h:4096 [inline]
 __ext4_check_dir_entry+0x65a/0xc40 fs/ext4/dir.c:96
 ext4_find_dest_de+0x136/0x770 fs/ext4/namei.c:2203
 ext4_add_dirent_to_inline+0xcf/0x430 fs/ext4/inline.c:984
 ext4_try_add_inline_entry+0x235/0x8e0 fs/ext4/inline.c:1213
 __ext4_add_entry+0x390/0x1f40 fs/ext4/namei.c:2529
 ext4_add_entry fs/ext4/namei.c:2613 [inline]
 ext4_add_nondir+0x111/0x310 fs/ext4/namei.c:2936
 ext4_create+0x2e9/0x470 fs/ext4/namei.c:2982
 lookup_open fs/namei.c:4511 [inline]
 open_last_lookups fs/namei.c:4611 [inline]
 path_openat+0x1395/0x3860 fs/namei.c:4855
 do_file_open+0x23e/0x4a0 fs/namei.c:4887
 do_sys_openat2+0x113/0x200 fs/open.c:1364
 do_sys_open fs/open.c:1370 [inline]
 __do_sys_openat fs/open.c:1386 [inline]
 __se_sys_openat fs/open.c:1381 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1381
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f922219ce59
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:00007f9223137028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f9222415fa0 RCX: 00007f922219ce59
RDX: 0000000000042042 RSI: 0000200000000080 RDI: 0000000000000004
RBP: 00007f9222232d6f R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000014a R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9222416038 R14: 00007f9222415fa0 R15: 00007ffd01a2d448
 </TASK>

Allocated by task 5484:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 unpoison_slab_object mm/kasan/common.c:340 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4570 [inline]
 slab_alloc_node mm/slub.c:4899 [inline]
 kmem_cache_alloc_node_noprof+0x384/0x690 mm/slub.c:4951
 kmalloc_reserve net/core/skbuff.c:613 [inline]
 __alloc_skb+0x27d/0x7d0 net/core/skbuff.c:713
 alloc_skb include/linux/skbuff.h:1385 [inline]
 nlmsg_new include/net/netlink.h:1055 [inline]
 mpls_netconf_notify_devconf+0x46/0x100 net/mpls/af_mpls.c:1217
 mpls_dev_notify+0xb2d/0xd10 net/mpls/af_mpls.c:1691
 notifier_call_chain+0x1ad/0x3d0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2287 [inline]
 call_netdevice_notifiers net/core/dev.c:2301 [inline]
 unregister_netdevice_many_notify+0x17a5/0x22c0 net/core/dev.c:12421
 ops_exit_rtnl_list net/core/net_namespace.c:187 [inline]
 ops_undo_list+0x3d3/0x940 net/core/net_namespace.c:248
 cleanup_net+0x56b/0x800 net/core/net_namespace.c:702
 process_one_work kernel/workqueue.c:3314 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478
 kthread+0x389/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 5484:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2689 [inline]
 slab_free mm/slub.c:6251 [inline]
 kfree+0x1c5/0x640 mm/slub.c:6566
 skb_kfree_head net/core/skbuff.c:1075 [inline]
 skb_free_head net/core/skbuff.c:1087 [inline]
 skb_release_data+0x828/0xa60 net/core/skbuff.c:1114
 skb_release_all net/core/skbuff.c:1189 [inline]
 __kfree_skb+0x5d/0x210 net/core/skbuff.c:1203
 netlink_broadcast_filtered+0xe18/0xf20 net/netlink/af_netlink.c:1540
 nlmsg_multicast_filtered include/net/netlink.h:1165 [inline]
 nlmsg_multicast include/net/netlink.h:1184 [inline]
 nlmsg_notify+0xf0/0x1a0 net/netlink/af_netlink.c:2598
 mpls_dev_notify+0xb2d/0xd10 net/mpls/af_mpls.c:1691
 notifier_call_chain+0x1ad/0x3d0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2287 [inline]
 call_netdevice_notifiers net/core/dev.c:2301 [inline]
 unregister_netdevice_many_notify+0x17a5/0x22c0 net/core/dev.c:12421
 ops_exit_rtnl_list net/core/net_namespace.c:187 [inline]
 ops_undo_list+0x3d3/0x940 net/core/net_namespace.c:248
 cleanup_net+0x56b/0x800 net/core/net_namespace.c:702
 process_one_work kernel/workqueue.c:3314 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478
 kthread+0x389/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff888114d8c000
 which belongs to the cache skbuff_small_head of size 704
The buggy address is located 69 bytes inside of
 freed 704-byte region [ffff888114d8c000, ffff888114d8c2c0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x114d8c
head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x17ff00000000040(head|node=0|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 017ff00000000040 ffff888160416b40 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800120012 00000000f5000000 0000000000000000
head: 017ff00000000040 ffff888160416b40 dead000000000100 dead000000000122
head: 0000000000000000 0000000800120012 00000000f5000000 0000000000000000
head: 017ff00000000002 ffffffffffffff01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5484, tgid 5484 (kworker/u8:2), ts 72573003529, free_ts 72546506446
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x22d/0x280 mm/page_alloc.c:1853
 prep_new_page mm/page_alloc.c:1861 [inline]
 get_page_from_freelist+0x2593/0x2610 mm/page_alloc.c:3941
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5221
 alloc_slab_page mm/slub.c:3278 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3467
 new_slab mm/slub.c:3525 [inline]
 refill_objects+0x339/0x3d0 mm/slub.c:7272
 refill_sheaf mm/slub.c:2816 [inline]
 __pcs_replace_empty_main+0x321/0x720 mm/slub.c:4652
 alloc_from_pcs mm/slub.c:4750 [inline]
 slab_alloc_node mm/slub.c:4884 [inline]
 kmem_cache_alloc_node_noprof+0x441/0x690 mm/slub.c:4951
 kmalloc_reserve net/core/skbuff.c:613 [inline]
 __alloc_skb+0x27d/0x7d0 net/core/skbuff.c:713
 alloc_skb include/linux/skbuff.h:1385 [inline]
 nlmsg_new include/net/netlink.h:1055 [inline]
 mpls_netconf_notify_devconf+0x46/0x100 net/mpls/af_mpls.c:1217
 mpls_dev_notify+0xb2d/0xd10 net/mpls/af_mpls.c:1691
 notifier_call_chain+0x1ad/0x3d0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2287 [inline]
 call_netdevice_notifiers net/core/dev.c:2301 [inline]
 unregister_netdevice_many_notify+0x17a5/0x22c0 net/core/dev.c:12421
 ops_exit_rtnl_list net/core/net_namespace.c:187 [inline]
 ops_undo_list+0x3d3/0x940 net/core/net_namespace.c:248
 cleanup_net+0x56b/0x800 net/core/net_namespace.c:702
 process_one_work kernel/workqueue.c:3314 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478
page last free pid 5484 tgid 5484 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1397 [inline]
 __free_frozen_pages+0xc1c/0xd30 mm/page_alloc.c:2938
 stack_depot_save_flags+0x40e/0x810 lib/stackdepot.c:735
 kasan_save_stack mm/kasan/common.c:58 [inline]
 kasan_save_track+0x4f/0x80 mm/kasan/common.c:78
 unpoison_slab_object mm/kasan/common.c:340 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4570 [inline]
 slab_alloc_node mm/slub.c:4899 [inline]
 kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4906
 kmem_alloc_batch lib/debugobjects.c:371 [inline]
 fill_pool+0x156/0x580 lib/debugobjects.c:420
 debug_objects_fill_pool lib/debugobjects.c:752 [inline]
 debug_object_activate+0x4a3/0x580 lib/debugobjects.c:841
 debug_rcu_head_queue kernel/rcu/rcu.h:236 [inline]
 __call_rcu_common kernel/rcu/tree.c:3116 [inline]
 call_rcu+0x43/0x890 kernel/rcu/tree.c:3251
 kernfs_put+0x259/0x520 fs/kernfs/dir.c:618
 kernfs_remove_by_name_ns+0xc8/0x140 fs/kernfs/dir.c:1799
 device_remove_class_symlinks+0x178/0x190 drivers/base/core.c:3479
 device_del+0x400/0x8f0 drivers/base/core.c:3881
 unregister_netdevice_many_notify+0x1d5f/0x22c0 net/core/dev.c:12456
 ops_exit_rtnl_list net/core/net_namespace.c:187 [inline]
 ops_undo_list+0x3d3/0x940 net/core/net_namespace.c:248
 cleanup_net+0x56b/0x800 net/core/net_namespace.c:702
 process_one_work kernel/workqueue.c:3314 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397

Memory state around the buggy address:
 ffff888114d8bf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888114d8bf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888114d8c000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff888114d8c080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888114d8c100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


***

KASAN: slab-use-after-free Read in ext4_inlinedir_to_tree

tree:      torvalds
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base:      9716c086c8e8b141d35aa61f2e96a2e83de212a7
arch:      amd64
compiler:  Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
config:    https://ci.syzbot.org/builds/ddf6ee7c-dfa8-4383-b004-10140edc081c/config
syz repro: https://ci.syzbot.org/findings/f42da242-e16e-4f10-bf25-0bd7e192d989/syz_repro

loop0: lost filesystem error report for type 5 error -117
EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.
==================================================================
BUG: KASAN: slab-use-after-free in ext4_dirent_get_data_len fs/ext4/ext4.h:4069 [inline]
BUG: KASAN: slab-use-after-free in ext4_dir_entry_len fs/ext4/ext4.h:4096 [inline]
BUG: KASAN: slab-use-after-free in ext4_inlinedir_to_tree+0x94c/0x10d0 fs/ext4/inline.c:1335
Read of size 1 at addr ffff88816fee8825 by task syz.0.20/5867

CPU: 1 UID: 0 PID: 5867 Comm: syz.0.20 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 ext4_dirent_get_data_len fs/ext4/ext4.h:4069 [inline]
 ext4_dir_entry_len fs/ext4/ext4.h:4096 [inline]
 ext4_inlinedir_to_tree+0x94c/0x10d0 fs/ext4/inline.c:1335
 ext4_htree_fill_tree+0x517/0x1230 fs/ext4/namei.c:1182
 ext4_dx_readdir fs/ext4/dir.c:600 [inline]
 ext4_readdir+0x2db4/0x3640 fs/ext4/dir.c:146
 iterate_dir+0x399/0x570 fs/readdir.c:110
 __do_sys_getdents fs/readdir.c:319 [inline]
 __se_sys_getdents+0xf1/0x270 fs/readdir.c:304
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f010ad9ce59
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:00007f010bc0f028 EFLAGS: 00000246 ORIG_RAX: 000000000000004e
RAX: ffffffffffffffda RBX: 00007f010b015fa0 RCX: 00007f010ad9ce59
RDX: 0000000000000054 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f010ae32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f010b016038 R14: 00007f010b015fa0 R15: 00007ffd93577348
 </TASK>

Allocated by task 5064:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5296 [inline]
 __kmalloc_noprof+0x35c/0x760 mm/slub.c:5308
 kmalloc_noprof include/linux/slab.h:954 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 tomoyo_encode2 security/tomoyo/realpath.c:45 [inline]
 tomoyo_encode+0x28b/0x550 security/tomoyo/realpath.c:80
 tomoyo_realpath_from_path+0x58d/0x5d0 security/tomoyo/realpath.c:283
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_perm+0x283/0x560 security/tomoyo/file.c:827
 security_inode_getattr+0x12b/0x310 security/security.c:1895
 vfs_getattr fs/stat.c:259 [inline]
 vfs_fstat fs/stat.c:281 [inline]
 vfs_fstatat+0xb4/0x170 fs/stat.c:371
 __do_sys_newfstatat fs/stat.c:538 [inline]
 __se_sys_newfstatat fs/stat.c:532 [inline]
 __x64_sys_newfstatat+0x151/0x200 fs/stat.c:532
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5064:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2689 [inline]
 slab_free mm/slub.c:6251 [inline]
 kfree+0x1c5/0x640 mm/slub.c:6566
 tomoyo_path_perm+0x403/0x560 security/tomoyo/file.c:847
 security_inode_getattr+0x12b/0x310 security/security.c:1895
 vfs_getattr fs/stat.c:259 [inline]
 vfs_fstat fs/stat.c:281 [inline]
 vfs_fstatat+0xb4/0x170 fs/stat.c:371
 __do_sys_newfstatat fs/stat.c:538 [inline]
 __se_sys_newfstatat fs/stat.c:532 [inline]
 __x64_sys_newfstatat+0x151/0x200 fs/stat.c:532
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88816fee8800
 which belongs to the cache kmalloc-64 of size 64
The buggy address is located 37 bytes inside of
 freed 64-byte region [ffff88816fee8800, ffff88816fee8840)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x16fee8
flags: 0x57ff00000000000(node=1|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 057ff00000000000 ffff8881000418c0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800200020 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 21294026082, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x22d/0x280 mm/page_alloc.c:1853
 prep_new_page mm/page_alloc.c:1861 [inline]
 get_page_from_freelist+0x2593/0x2610 mm/page_alloc.c:3941
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5221
 alloc_slab_page mm/slub.c:3278 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3467
 new_slab mm/slub.c:3525 [inline]
 refill_objects+0x339/0x3d0 mm/slub.c:7272
 refill_sheaf mm/slub.c:2816 [inline]
 __pcs_replace_empty_main+0x321/0x720 mm/slub.c:4652
 alloc_from_pcs mm/slub.c:4750 [inline]
 slab_alloc_node mm/slub.c:4884 [inline]
 __do_kmalloc_node mm/slub.c:5295 [inline]
 __kmalloc_noprof+0x474/0x760 mm/slub.c:5308
 kmalloc_noprof include/linux/slab.h:954 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 handler_new_ref+0x261/0x9c0 drivers/media/v4l2-core/v4l2-ctrls-core.c:1882
 v4l2_ctrl_add_handler+0x19f/0x290 drivers/media/v4l2-core/v4l2-ctrls-core.c:2443
 vivid_create_controls+0x332d/0x3bd0 drivers/media/test-drivers/vivid/vivid-ctrls.c:2072
 vivid_create_instance drivers/media/test-drivers/vivid/vivid-core.c:1933 [inline]
 vivid_probe+0x4261/0x72b0 drivers/media/test-drivers/vivid/vivid-core.c:2095
 platform_probe+0xf9/0x190 drivers/base/platform.c:1432
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x267/0xaf0 drivers/base/dd.c:709
 __driver_probe_device+0x1ef/0x380 drivers/base/dd.c:871
 driver_probe_device+0x4f/0x240 drivers/base/dd.c:901
 __driver_attach+0x34c/0x640 drivers/base/dd.c:1295
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88816fee8700: 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc
 ffff88816fee8780: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
>ffff88816fee8800: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
                               ^
 ffff88816fee8880: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff88816fee8900: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================


***

KASAN: use-after-free Read in __ext4_check_dir_entry

tree:      torvalds
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux
base:      9716c086c8e8b141d35aa61f2e96a2e83de212a7
arch:      amd64
compiler:  Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
config:    https://ci.syzbot.org/builds/ddf6ee7c-dfa8-4383-b004-10140edc081c/config
syz repro: https://ci.syzbot.org/findings/57c0b75a-8922-4dc1-9a20-ca947564792b/syz_repro

==================================================================
BUG: KASAN: use-after-free in ext4_dirent_get_data_len fs/ext4/ext4.h:4069 [inline]
BUG: KASAN: use-after-free in ext4_dir_entry_len fs/ext4/ext4.h:4096 [inline]
BUG: KASAN: use-after-free in __ext4_check_dir_entry+0x65a/0xc40 fs/ext4/dir.c:96
Read of size 1 at addr ffff88816be85045 by task syz.2.21/5880

CPU: 1 UID: 0 PID: 5880 Comm: syz.2.21 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 ext4_dirent_get_data_len fs/ext4/ext4.h:4069 [inline]
 ext4_dir_entry_len fs/ext4/ext4.h:4096 [inline]
 __ext4_check_dir_entry+0x65a/0xc40 fs/ext4/dir.c:96
 ext4_find_dest_de+0x136/0x770 fs/ext4/namei.c:2203
 ext4_add_dirent_to_inline+0xcf/0x430 fs/ext4/inline.c:984
 ext4_try_add_inline_entry+0x235/0x8e0 fs/ext4/inline.c:1213
 __ext4_add_entry+0x390/0x1f40 fs/ext4/namei.c:2529
 ext4_add_entry fs/ext4/namei.c:2613 [inline]
 ext4_add_nondir+0x111/0x310 fs/ext4/namei.c:2936
 ext4_create+0x2e9/0x470 fs/ext4/namei.c:2982
 lookup_open fs/namei.c:4511 [inline]
 open_last_lookups fs/namei.c:4611 [inline]
 path_openat+0x1395/0x3860 fs/namei.c:4855
 do_file_open+0x23e/0x4a0 fs/namei.c:4887
 do_sys_openat2+0x113/0x200 fs/open.c:1364
 do_sys_open fs/open.c:1370 [inline]
 __do_sys_openat fs/open.c:1386 [inline]
 __se_sys_openat fs/open.c:1381 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1381
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5713b9ce59
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:00007fff672b25f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f5713e15fa0 RCX: 00007f5713b9ce59
RDX: 0000000000042042 RSI: 0000200000000080 RDI: 0000000000000004
RBP: 00007f5713c32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000014a R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5713e15fac R14: 00007f5713e15fa0 R15: 00007f5713e15fa0
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x16be85
flags: 0x57ff00000000000(node=1|zone=2|lastcpupid=0x7ff)
page_type: f0(buddy)
raw: 057ff00000000000 ffffea0005afa0c8 ffffea0005afa1c8 0000000000000000
raw: 0000000000000000 0000000000000000 00000000f0000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Unmovable, gfp_mask 0xcc0(GFP_KERNEL), pid 5630, tgid 5630 (syz-executor), ts 67290853657, free_ts 69321168948
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x22d/0x280 mm/page_alloc.c:1853
 prep_new_page mm/page_alloc.c:1861 [inline]
 get_page_from_freelist+0x2593/0x2610 mm/page_alloc.c:3941
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5221
 __alloc_pages_noprof+0x10/0x100 mm/page_alloc.c:5255
 alloc_pages_bulk_noprof+0x5ff/0x7c0 mm/page_alloc.c:5175
 ___alloc_pages_bulk mm/kasan/shadow.c:345 [inline]
 __kasan_populate_vmalloc_do mm/kasan/shadow.c:370 [inline]
 __kasan_populate_vmalloc+0xc1/0x1d0 mm/kasan/shadow.c:424
 kasan_populate_vmalloc include/linux/kasan.h:580 [inline]
 alloc_vmap_area+0xd47/0x1480 mm/vmalloc.c:2123
 __get_vm_area_node+0x1f8/0x300 mm/vmalloc.c:3226
 __vmalloc_node_range_noprof+0x36a/0x1750 mm/vmalloc.c:4024
 vmalloc_user_noprof+0xad/0xe0 mm/vmalloc.c:4218
 kcov_ioctl+0x55/0x620 kernel/kcov.c:726
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5693 tgid 5693 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1397 [inline]
 __free_frozen_pages+0xc1c/0xd30 mm/page_alloc.c:2938
 kasan_depopulate_vmalloc_pte+0x6d/0x90 mm/kasan/shadow.c:484
 apply_to_pte_range mm/memory.c:3338 [inline]
 apply_to_pmd_range mm/memory.c:3382 [inline]
 apply_to_pud_range mm/memory.c:3418 [inline]
 apply_to_p4d_range mm/memory.c:3454 [inline]
 __apply_to_page_range+0xbdc/0x1420 mm/memory.c:3490
 __kasan_release_vmalloc+0xa2/0xd0 mm/kasan/shadow.c:602
 kasan_release_vmalloc include/linux/kasan.h:593 [inline]
 kasan_release_vmalloc_node mm/vmalloc.c:2284 [inline]
 purge_vmap_node+0x220/0x960 mm/vmalloc.c:2306
 __purge_vmap_area_lazy+0x779/0xb40 mm/vmalloc.c:2396
 drain_vmap_area_work+0x27/0x40 mm/vmalloc.c:2430
 process_one_work kernel/workqueue.c:3314 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478
 kthread+0x389/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff88816be84f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88816be84f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88816be85000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                           ^
 ffff88816be85080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88816be85100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================


***

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separate fix, please add the following tag to your commit message:
  Tested-by: syzbot@syzkaller.appspotmail.com

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