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

[syzbot ci <syzbot+cidbccf04ba3f3bc79@syzkaller.appspotmail.com>]

syzbot ci has tested the following series

[v3] Data in direntry (dirdata) feature
https://lore.kernel.org/all/20260619191022.27008-1-ablagodarenko@thelustrecollective.com
* [PATCH v3 01/10] ext4: replace ext4_dir_entry with ext4_dir_entry_2
* [PATCH v3 02/10] ext4: add ext4_dir_entry_is_tail()
* [PATCH v3 03/10] ext4: refactor dx_root to support variable dirent sizes
* [PATCH v3 04/10] ext4: add dirdata format definitions and access helpers
* [PATCH v3 05/10] ext4: preserve dirdata bits in get_dtype()
* [PATCH v3 06/10] ext4: add ext4_dir_entry_len() and harden dirdata parsing
* [PATCH v3 07/10] ext4: rename ext4_dir_rec_len() and clarify dirdata usage
* [PATCH v3 08/10] ext4: dirdata feature
* [PATCH v3 09/10] ext4: add dirdata set/get helpers
* [PATCH v3 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/a3c6e513-a6eb-4583-86f6-89176398b397

***

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:      08c7183f5b9ffe4408e74fff848a4cc2105361d4
arch:      amd64
compiler:  Debian clang version 22.1.6 (++20260514074242+fc4aad7b5db3-1~exp1~20260514074407.73), Debian LLD 22.1.6
config:    https://ci.syzbot.org/builds/0efdb868-daeb-4649-9bcb-5af41d993e73/config
syz repro: https://ci.syzbot.org/findings/ec557d64-7b60-46c9-a0eb-feaa7a3eb2cd/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:4156 [inline]
BUG: KASAN: slab-out-of-bounds in ext4_dir_entry_len fs/ext4/ext4.h:4183 [inline]
BUG: KASAN: slab-out-of-bounds in __ext4_check_dir_entry+0x659/0xbe0 fs/ext4/dir.c:96
Read of size 1 at addr ffff88816e86bcd9 by task syz.0.21/5783

CPU: 1 UID: 0 PID: 5783 Comm: syz.0.21 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:4156 [inline]
 ext4_dir_entry_len fs/ext4/ext4.h:4183 [inline]
 __ext4_check_dir_entry+0x659/0xbe0 fs/ext4/dir.c:96
 ext4_check_all_de+0x6a/0x140 fs/ext4/dir.c:657
 ext4_convert_inline_data_nolock+0x1b7/0x980 fs/ext4/inline.c:1121
 ext4_try_add_inline_entry+0x5cc/0x8a0 fs/ext4/inline.c:1247
 __ext4_add_entry+0x385/0x3470 fs/ext4/namei.c:2552
 ext4_add_entry fs/ext4/namei.c:2636 [inline]
 ext4_mkdir+0x5f3/0xd30 fs/ext4/namei.c:3203
 vfs_mkdir+0x406/0x620 fs/namei.c:5272
 filename_mkdirat+0x285/0x510 fs/namei.c:5305
 __do_sys_mkdirat fs/namei.c:5326 [inline]
 __se_sys_mkdirat+0x35/0x150 fs/namei.c:5323
 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: 0033:0x7fb4c839ce59
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:00007ffd4b254a88 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007fb4c8615fa0 RCX: 00007fb4c839ce59
RDX: 0000000000000037 RSI: 0000200000000380 RDI: 0000000000000004
RBP: 00007fb4c8432e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb4c8615fac R14: 00007fb4c8615fa0 R15: 00007fb4c8615fa0
 </TASK>

Allocated by task 5056:
 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+0x318/0x660 mm/slub.c:5451
 _kmalloc_noprof include/linux/slab.h:969 [inline]
 _kzalloc_noprof include/linux/slab.h:1286 [inline]
 kernfs_get_open_node fs/kernfs/file.c:536 [inline]
 kernfs_fop_open+0x7e6/0xce0 fs/kernfs/file.c:711
 do_dentry_open+0x816/0x1380 fs/open.c:947
 vfs_open+0x3b/0x340 fs/open.c:1079
 do_open fs/namei.c:4700 [inline]
 path_openat+0x2e44/0x3830 fs/namei.c:4859
 do_file_open+0x23e/0x4a0 fs/namei.c:4888
 do_sys_openat2+0x115/0x200 fs/open.c:1395
 do_sys_open fs/open.c:1401 [inline]
 __do_sys_openat fs/open.c:1417 [inline]
 __se_sys_openat fs/open.c:1412 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1412
 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 ffff88816e86bc00
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 89 bytes to the right of
 allocated 128-byte region [ffff88816e86bc00, ffff88816e86bc80)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88816e86bf00 pfn:0x16e86b
flags: 0x57ff00000000200(workingset|node=1|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 057ff00000000200 ffff888100041a00 ffff888160400648 ffff888160400648
raw: ffff88816e86bf00 000000080010000f 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 5056, tgid 5056 (udevd), ts 53238350188, free_ts 53091667410
 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+0x24ae/0x2530 mm/page_alloc.c:3941
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5221
 alloc_slab_page mm/slub.c:3289 [inline]
 allocate_slab+0x74/0x5d0 mm/slub.c:3404
 new_slab mm/slub.c:3447 [inline]
 refill_objects+0x328/0x3c0 mm/slub.c:7241
 refill_sheaf mm/slub.c:2827 [inline]
 __pcs_replace_empty_main+0x2e0/0x6b0 mm/slub.c:4692
 alloc_from_pcs mm/slub.c:4790 [inline]
 slab_alloc_node mm/slub.c:4924 [inline]
 __kmalloc_cache_noprof+0x388/0x660 mm/slub.c:5446
 _kmalloc_noprof include/linux/slab.h:969 [inline]
 _kzalloc_noprof include/linux/slab.h:1286 [inline]
 kernfs_get_open_node fs/kernfs/file.c:536 [inline]
 kernfs_fop_open+0x7e6/0xce0 fs/kernfs/file.c:711
 do_dentry_open+0x816/0x1380 fs/open.c:947
 vfs_open+0x3b/0x340 fs/open.c:1079
 do_open fs/namei.c:4700 [inline]
 path_openat+0x2e44/0x3830 fs/namei.c:4859
 do_file_open+0x23e/0x4a0 fs/namei.c:4888
 do_sys_openat2+0x115/0x200 fs/open.c:1395
 do_sys_open fs/open.c:1401 [inline]
 __do_sys_openat fs/open.c:1417 [inline]
 __se_sys_openat fs/open.c:1412 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1412
 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 23 tgid 23 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1397 [inline]
 __free_frozen_pages+0xc0d/0xd20 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:2645 [inline]
 rcu_core+0x78b/0x10a0 kernel/rcu/tree.c:2897
 handle_softirqs+0x225/0x840 kernel/softirq.c:622
 run_ksoftirqd+0x36/0x60 kernel/softirq.c:1076
 smpboot_thread_fn+0x57c/0xa80 kernel/smpboot.c:160
 kthread+0x388/0x470 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:
 ffff88816e86bb80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88816e86bc00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88816e86bc80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                                    ^
 ffff88816e86bd00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88816e86bd80: 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:      08c7183f5b9ffe4408e74fff848a4cc2105361d4
arch:      amd64
compiler:  Debian clang version 22.1.6 (++20260514074242+fc4aad7b5db3-1~exp1~20260514074407.73), Debian LLD 22.1.6
config:    https://ci.syzbot.org/builds/0efdb868-daeb-4649-9bcb-5af41d993e73/config
syz repro: https://ci.syzbot.org/findings/bb78d414-4cff-400b-aaf6-76d450b12cda/syz_repro

==================================================================
BUG: KASAN: slab-out-of-bounds in ext4_dir_entry_len fs/ext4/ext4.h:4182 [inline]
BUG: KASAN: slab-out-of-bounds in ext4_inlinedir_to_tree+0xd95/0x10a0 fs/ext4/inline.c:1335
Read of size 2 at addr ffff88816f219a3c by task syz.1.18/5830

CPU: 1 UID: 0 PID: 5830 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:4182 [inline]
 ext4_inlinedir_to_tree+0xd95/0x10a0 fs/ext4/inline.c:1335
 ext4_htree_fill_tree+0x4c9/0x2480 fs/ext4/namei.c:1195
 ext4_dx_readdir fs/ext4/dir.c:600 [inline]
 ext4_readdir+0x2e2a/0x3720 fs/ext4/dir.c:146
 iterate_dir+0x2e2/0x4d0 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: 0033:0x7fe51459ce59
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:00007fe515527028 EFLAGS: 00000246 ORIG_RAX: 000000000000004e
RAX: ffffffffffffffda RBX: 00007fe514815fa0 RCX: 00007fe51459ce59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006
RBP: 00007fe514632e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe514816038 R14: 00007fe514815fa0 R15: 00007fffd9b381d8
 </TASK>

Allocated by task 5830:
 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:5334 [inline]
 __kmalloc_noprof+0x358/0x750 mm/slub.c:5347
 _kmalloc_noprof include/linux/slab.h:973 [inline]
 ext4_inlinedir_to_tree+0x2ec/0x10a0 fs/ext4/inline.c:1292
 ext4_htree_fill_tree+0x4c9/0x2480 fs/ext4/namei.c:1195
 ext4_dx_readdir fs/ext4/dir.c:600 [inline]
 ext4_readdir+0x2e2a/0x3720 fs/ext4/dir.c:146
 iterate_dir+0x2e2/0x4d0 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

The buggy address belongs to the object at ffff88816f219a00
 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 [ffff88816f219a00, ffff88816f219a3c)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x16f219
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 10138712683, free_ts 10137977139
 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+0x24ae/0x2530 mm/page_alloc.c:3941
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5221
 alloc_slab_page mm/slub.c:3289 [inline]
 allocate_slab+0x74/0x5d0 mm/slub.c:3404
 new_slab mm/slub.c:3447 [inline]
 refill_objects+0x328/0x3c0 mm/slub.c:7241
 refill_sheaf mm/slub.c:2827 [inline]
 __pcs_replace_empty_main+0x2e0/0x6b0 mm/slub.c:4692
 alloc_from_pcs mm/slub.c:4790 [inline]
 slab_alloc_node mm/slub.c:4924 [inline]
 __do_kmalloc_node mm/slub.c:5333 [inline]
 __kmalloc_noprof+0x464/0x750 mm/slub.c:5347
 _kmalloc_noprof include/linux/slab.h:973 [inline]
 _kzalloc_noprof include/linux/slab.h:1286 [inline]
 kobject_get_path+0xc5/0x2f0 lib/kobject.c:161
 kobject_uevent_env+0x29e/0x9e0 lib/kobject_uevent.c:548
 device_add+0x544/0xb80 drivers/base/core.c:3738
 scsi_add_host_with_dma+0x5db/0xd00 drivers/scsi/hosts.c:287
 ata_scsi_add_hosts+0x29b/0x4b0 drivers/ata/libata-scsi.c:4659
 ata_host_register+0x1c5/0x7d0 drivers/ata/libata-core.c:6131
 ata_host_activate+0x33c/0x3c0 drivers/ata/libata-core.c:6234
 ahci_init_one+0x1afa/0x22b0 drivers/ata/ahci.c:3090
 local_pci_probe drivers/pci/pci-driver.c:332 [inline]
 pci_call_probe drivers/pci/pci-driver.c:394 [inline]
 __pci_device_probe drivers/pci/pci-driver.c:455 [inline]
 pci_device_probe+0x431/0xc90 drivers/pci/pci-driver.c:489
page last free pid 36 tgid 36 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1397 [inline]
 __free_frozen_pages+0xc0d/0xd20 mm/page_alloc.c:2938
 __kasan_populate_vmalloc_do mm/kasan/shadow.c:393 [inline]
 __kasan_populate_vmalloc+0x1a8/0x1c0 mm/kasan/shadow.c:424
 kasan_populate_vmalloc include/linux/kasan.h:580 [inline]
 alloc_vmap_area+0xd1a/0x1420 mm/vmalloc.c:2123
 __get_vm_area_node+0x1f2/0x300 mm/vmalloc.c:3226
 __vmalloc_node_range_noprof+0x358/0x1730 mm/vmalloc.c:4024
 __vmalloc_node_noprof+0xc2/0x100 mm/vmalloc.c:4124
 alloc_thread_stack_node kernel/fork.c:358 [inline]
 dup_task_struct+0x28e/0x850 kernel/fork.c:928
 copy_process+0x81b/0x42e0 kernel/fork.c:2109
 kernel_clone+0x2d7/0x940 kernel/fork.c:2745
 user_mode_thread+0x110/0x180 kernel/fork.c:2821
 call_usermodehelper_exec_work+0x5c/0x230 kernel/umh.c:171
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
 kthread+0x388/0x470 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:
 ffff88816f219900: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
 ffff88816f219980: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff88816f219a00: 00 00 00 00 00 00 00 04 fc fc fc fc fc fc fc fc
                                        ^
 ffff88816f219a80: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff88816f219b00: 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:      08c7183f5b9ffe4408e74fff848a4cc2105361d4
arch:      amd64
compiler:  Debian clang version 22.1.6 (++20260514074242+fc4aad7b5db3-1~exp1~20260514074407.73), Debian LLD 22.1.6
config:    https://ci.syzbot.org/builds/0efdb868-daeb-4649-9bcb-5af41d993e73/config
syz repro: https://ci.syzbot.org/findings/f322e293-7a3f-469a-ae1f-677c84eb4c0f/syz_repro

==================================================================
BUG: KASAN: slab-use-after-free in ext4_dirent_get_data_len fs/ext4/ext4.h:4156 [inline]
BUG: KASAN: slab-use-after-free in ext4_dir_entry_len fs/ext4/ext4.h:4183 [inline]
BUG: KASAN: slab-use-after-free in __ext4_check_dir_entry+0x659/0xbe0 fs/ext4/dir.c:96
Read of size 1 at addr ffff888103e89c1d by task syz.2.19/5867

CPU: 0 UID: 0 PID: 5867 Comm: syz.2.19 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:4156 [inline]
 ext4_dir_entry_len fs/ext4/ext4.h:4183 [inline]
 __ext4_check_dir_entry+0x659/0xbe0 fs/ext4/dir.c:96
 ext4_check_all_de+0x6a/0x140 fs/ext4/dir.c:657
 ext4_convert_inline_data_nolock+0x1b7/0x980 fs/ext4/inline.c:1121
 ext4_try_add_inline_entry+0x5cc/0x8a0 fs/ext4/inline.c:1247
 __ext4_add_entry+0x385/0x3470 fs/ext4/namei.c:2552
 ext4_add_entry fs/ext4/namei.c:2636 [inline]
 ext4_mkdir+0x5f3/0xd30 fs/ext4/namei.c:3203
 vfs_mkdir+0x406/0x620 fs/namei.c:5272
 filename_mkdirat+0x285/0x510 fs/namei.c:5305
 __do_sys_mkdirat fs/namei.c:5326 [inline]
 __se_sys_mkdirat+0x35/0x150 fs/namei.c:5323
 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: 0033:0x7fb01d39ce59
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:00007fb01e269028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007fb01d615fa0 RCX: 00007fb01d39ce59
RDX: 0000000000000037 RSI: 0000200000000380 RDI: 0000000000000004
RBP: 00007fb01d432e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fb01d616038 R14: 00007fb01d615fa0 R15: 00007ffdec822cc8
 </TASK>

Allocated by task 5630:
 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+0x318/0x660 mm/slub.c:5451
 _kmalloc_noprof include/linux/slab.h:969 [inline]
 __hw_addr_create+0x62/0x240 net/core/dev_addr_lists.c:69
 __hw_addr_add_ex+0x1ce/0x520 net/core/dev_addr_lists.c:127
 __hw_addr_add net/core/dev_addr_lists.c:144 [inline]
 dev_addr_init+0x15a/0x240 net/core/dev_addr_lists.c:696
 alloc_netdev_mqs+0x2b4/0x1270 net/core/dev.c:12064
 __ip_tunnel_create+0x348/0x560 net/ipv4/ip_tunnel.c:255
 ip_tunnel_init_net+0x2ea/0x810 net/ipv4/ip_tunnel.c:1150
 ops_init+0x35d/0x5d0 net/core/net_namespace.c:137
 setup_net+0x118/0x350 net/core/net_namespace.c:446
 copy_net_ns+0x4f9/0x720 net/core/net_namespace.c:579
 create_new_namespaces+0x3f0/0x6b0 kernel/nsproxy.c:132
 unshare_nsproxy_namespaces+0x149/0x190 kernel/nsproxy.c:234
 ksys_unshare+0x57d/0xa00 kernel/fork.c:3266
 __do_sys_unshare kernel/fork.c:3340 [inline]
 __se_sys_unshare kernel/fork.c:3338 [inline]
 __x64_sys_unshare+0x38/0x50 kernel/fork.c:3338
 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 68:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x40/0x50 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:2700 [inline]
 slab_free_freelist_hook mm/slub.c:2729 [inline]
 slab_free_bulk mm/slub.c:6344 [inline]
 kmem_cache_free_bulk+0x30f/0x1180 mm/slub.c:7076
 kfree_bulk include/linux/slab.h:891 [inline]
 kvfree_rcu_bulk+0xc6/0x190 mm/slab_common.c:1502
 kvfree_rcu_drain_ready mm/slab_common.c:1704 [inline]
 kfree_rcu_monitor+0x21a/0x2b0 mm/slab_common.c:1777
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
 kthread+0x388/0x470 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

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
 __hw_addr_flush net/core/dev_addr_lists.c:500 [inline]
 dev_addr_flush+0x16c/0x210 net/core/dev_addr_lists.c:673
 free_netdev+0x26c/0x6e0 net/core/dev.c:12209
 netdev_run_todo+0xf3d/0x10d0 net/core/dev.c:11743
 ops_exit_rtnl_list net/core/net_namespace.c:189 [inline]
 ops_undo_list+0x396/0x8d0 net/core/net_namespace.c:248
 cleanup_net+0x572/0x810 net/core/net_namespace.c:702
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
 kthread+0x388/0x470 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 ffff888103e89c00
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 29 bytes inside of
 freed 128-byte region [ffff888103e89c00, ffff888103e89c80)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x103e89
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 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 2773920656, 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+0x24ae/0x2530 mm/page_alloc.c:3941
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5221
 alloc_slab_page mm/slub.c:3289 [inline]
 allocate_slab+0x74/0x5d0 mm/slub.c:3404
 new_slab mm/slub.c:3447 [inline]
 refill_objects+0x328/0x3c0 mm/slub.c:7241
 refill_sheaf mm/slub.c:2827 [inline]
 __pcs_replace_empty_main+0x2e0/0x6b0 mm/slub.c:4692
 alloc_from_pcs mm/slub.c:4790 [inline]
 slab_alloc_node mm/slub.c:4924 [inline]
 __do_kmalloc_node mm/slub.c:5333 [inline]
 __kmalloc_noprof+0x464/0x750 mm/slub.c:5347
 _kmalloc_noprof include/linux/slab.h:973 [inline]
 _kzalloc_noprof include/linux/slab.h:1286 [inline]
 __alloc_empty_sheaf+0x24/0x40 mm/slub.c:2774
 alloc_empty_sheaf mm/slub.c:2794 [inline]
 __pcs_replace_empty_main+0x447/0x6b0 mm/slub.c:4687
 alloc_from_pcs mm/slub.c:4790 [inline]
 slab_alloc_node mm/slub.c:4924 [inline]
 kmem_cache_alloc_lru_noprof+0x372/0x640 mm/slub.c:4958
 alloc_inode+0x6a/0x1b0 fs/inode.c:341
 new_inode+0x1f/0x170 fs/inode.c:1177
 debugfs_get_inode fs/debugfs/inode.c:72 [inline]
 debugfs_create_dir+0x68/0x350 fs/debugfs/inode.c:578
 blk_dev_init+0xdf/0x150 block/blk-core.c:1333
 genhd_device_init+0x1c/0x50 block/genhd.c:1002
 do_one_initcall+0x250/0x870 init/main.c:1347
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888103e89b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888103e89b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888103e89c00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff888103e89c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888103e89d00: fa 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:      08c7183f5b9ffe4408e74fff848a4cc2105361d4
arch:      amd64
compiler:  Debian clang version 22.1.6 (++20260514074242+fc4aad7b5db3-1~exp1~20260514074407.73), Debian LLD 22.1.6
config:    https://ci.syzbot.org/builds/0efdb868-daeb-4649-9bcb-5af41d993e73/config
syz repro: https://ci.syzbot.org/findings/b1e2a550-a6c3-410a-ae53-ca1e5366cc94/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:4156 [inline]
BUG: KASAN: slab-use-after-free in ext4_dir_entry_len fs/ext4/ext4.h:4183 [inline]
BUG: KASAN: slab-use-after-free in ext4_inlinedir_to_tree+0x8f0/0x10a0 fs/ext4/inline.c:1335
Read of size 1 at addr ffff888111d0149d by task syz.0.19/5801

CPU: 1 UID: 0 PID: 5801 Comm: syz.0.19 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:4156 [inline]
 ext4_dir_entry_len fs/ext4/ext4.h:4183 [inline]
 ext4_inlinedir_to_tree+0x8f0/0x10a0 fs/ext4/inline.c:1335
 ext4_htree_fill_tree+0x4c9/0x2480 fs/ext4/namei.c:1195
 ext4_dx_readdir fs/ext4/dir.c:600 [inline]
 ext4_readdir+0x2e2a/0x3720 fs/ext4/dir.c:146
 iterate_dir+0x2e2/0x4d0 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: 0033:0x7f6e8459ce59
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:00007ffef0bce788 EFLAGS: 00000246 ORIG_RAX: 000000000000004e
RAX: ffffffffffffffda RBX: 00007f6e84815fa0 RCX: 00007f6e8459ce59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007f6e84632e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6e84815fac R14: 00007f6e84815fa0 R15: 00007f6e84815fa0
 </TASK>

Allocated by task 5738:
 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+0x318/0x660 mm/slub.c:5451
 _kmalloc_noprof include/linux/slab.h:969 [inline]
 __kthread_create_on_node+0x115/0x3d0 kernel/kthread.c:483
 kthread_create_on_node+0xeb/0x140 kernel/kthread.c:559
 napi_kthread_create net/core/dev.c:1656 [inline]
 netif_napi_add_weight_locked+0x699/0x940 net/core/dev.c:7594
 netif_napi_add_weight include/linux/netdevice.h:2870 [inline]
 netif_napi_add include/linux/netdevice.h:2887 [inline]
 wg_peer_create+0x52d/0x860 drivers/net/wireguard/peer.c:57
 set_peer drivers/net/wireguard/netlink.c:392 [inline]
 wg_set_device_doit+0xf3a/0x2120 drivers/net/wireguard/netlink.c:569
 genl_family_rcv_msg_doit+0x233/0x340 net/netlink/genetlink.c:1114
 genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
 genl_rcv_msg+0x614/0x7a0 net/netlink/genetlink.c:1209
 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x7bb/0x940 net/netlink/af_netlink.c:1345
 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900
 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:775
 __sock_sendmsg net/socket.c:790 [inline]
 __sys_sendto+0x408/0x5a0 net/socket.c:2252
 __do_sys_sendto net/socket.c:2259 [inline]
 __se_sys_sendto net/socket.c:2255 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2255
 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 5738:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x40/0x50 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:2700 [inline]
 slab_free mm/slub.c:6310 [inline]
 kfree+0x1c5/0x640 mm/slub.c:6625
 __kthread_create_on_node+0x2fe/0x3d0 kernel/kthread.c:523
 kthread_create_on_node+0xeb/0x140 kernel/kthread.c:559
 napi_kthread_create net/core/dev.c:1656 [inline]
 netif_napi_add_weight_locked+0x699/0x940 net/core/dev.c:7594
 netif_napi_add_weight include/linux/netdevice.h:2870 [inline]
 netif_napi_add include/linux/netdevice.h:2887 [inline]
 wg_peer_create+0x52d/0x860 drivers/net/wireguard/peer.c:57
 set_peer drivers/net/wireguard/netlink.c:392 [inline]
 wg_set_device_doit+0xf3a/0x2120 drivers/net/wireguard/netlink.c:569
 genl_family_rcv_msg_doit+0x233/0x340 net/netlink/genetlink.c:1114
 genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
 genl_rcv_msg+0x614/0x7a0 net/netlink/genetlink.c:1209
 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x7bb/0x940 net/netlink/af_netlink.c:1345
 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900
 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:775
 __sock_sendmsg net/socket.c:790 [inline]
 __sys_sendto+0x408/0x5a0 net/socket.c:2252
 __do_sys_sendto net/socket.c:2259 [inline]
 __se_sys_sendto net/socket.c:2255 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2255
 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 ffff888111d01480
 which belongs to the cache kmalloc-64 of size 64
The buggy address is located 29 bytes inside of
 freed 64-byte region [ffff888111d01480, ffff888111d014c0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x111d01
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 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1113, tgid 1113 (kworker/u9:4), ts 18841797934, free_ts 18841792693
 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+0x24ae/0x2530 mm/page_alloc.c:3941
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5221
 alloc_slab_page mm/slub.c:3289 [inline]
 allocate_slab+0x74/0x5d0 mm/slub.c:3404
 new_slab mm/slub.c:3447 [inline]
 refill_objects+0x328/0x3c0 mm/slub.c:7241
 refill_sheaf mm/slub.c:2827 [inline]
 __pcs_replace_empty_main+0x2e0/0x6b0 mm/slub.c:4692
 alloc_from_pcs mm/slub.c:4790 [inline]
 slab_alloc_node mm/slub.c:4924 [inline]
 __do_kmalloc_node mm/slub.c:5333 [inline]
 __kmalloc_node_noprof+0x56a/0x7b0 mm/slub.c:5340
 _kmalloc_node_noprof include/linux/slab.h:1174 [inline]
 __vmalloc_area_node mm/vmalloc.c:3857 [inline]
 __vmalloc_node_range_noprof+0x5d9/0x1730 mm/vmalloc.c:4064
 __vmalloc_node_noprof+0xc2/0x100 mm/vmalloc.c:4124
 alloc_thread_stack_node kernel/fork.c:358 [inline]
 dup_task_struct+0x28e/0x850 kernel/fork.c:928
 copy_process+0x81b/0x42e0 kernel/fork.c:2109
 kernel_clone+0x2d7/0x940 kernel/fork.c:2745
 user_mode_thread+0x110/0x180 kernel/fork.c:2821
 call_usermodehelper_exec_work+0x5c/0x230 kernel/umh.c:171
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
page last free pid 1113 tgid 1113 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1397 [inline]
 __free_frozen_pages+0xc0d/0xd20 mm/page_alloc.c:2938
 __kasan_populate_vmalloc_do mm/kasan/shadow.c:393 [inline]
 __kasan_populate_vmalloc+0x1a8/0x1c0 mm/kasan/shadow.c:424
 kasan_populate_vmalloc include/linux/kasan.h:580 [inline]
 alloc_vmap_area+0xd1a/0x1420 mm/vmalloc.c:2123
 __get_vm_area_node+0x1f2/0x300 mm/vmalloc.c:3226
 __vmalloc_node_range_noprof+0x358/0x1730 mm/vmalloc.c:4024
 __vmalloc_node_noprof+0xc2/0x100 mm/vmalloc.c:4124
 alloc_thread_stack_node kernel/fork.c:358 [inline]
 dup_task_struct+0x28e/0x850 kernel/fork.c:928
 copy_process+0x81b/0x42e0 kernel/fork.c:2109
 kernel_clone+0x2d7/0x940 kernel/fork.c:2745
 user_mode_thread+0x110/0x180 kernel/fork.c:2821
 call_usermodehelper_exec_work+0x5c/0x230 kernel/umh.c:171
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
 kthread+0x388/0x470 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:
 ffff888111d01380: 00 00 00 00 00 00 00 04 fc fc fc fc fc fc fc fc
 ffff888111d01400: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff888111d01480: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
                            ^
 ffff888111d01500: 00 00 00 00 00 00 02 fc fc fc fc fc fc fc fc fc
 ffff888111d01580: 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:      08c7183f5b9ffe4408e74fff848a4cc2105361d4
arch:      amd64
compiler:  Debian clang version 22.1.6 (++20260514074242+fc4aad7b5db3-1~exp1~20260514074407.73), Debian LLD 22.1.6
config:    https://ci.syzbot.org/builds/0efdb868-daeb-4649-9bcb-5af41d993e73/config
syz repro: https://ci.syzbot.org/findings/07c4f835-36f6-4535-a165-aa25c5af571c/syz_repro

EXT4-fs error (device loop2): ext4_inlinedir_to_tree:1343: inode #21: block 10: comm syz.2.19: path /: bad entry in directory: directory entry overrun - offset=20, inode=0, rec_len=1024, size=60 fake=0
==================================================================
BUG: KASAN: use-after-free in ext4_dirent_get_data_len fs/ext4/ext4.h:4156 [inline]
BUG: KASAN: use-after-free in ext4_dir_entry_len fs/ext4/ext4.h:4183 [inline]
BUG: KASAN: use-after-free in __ext4_check_dir_entry+0x659/0xbe0 fs/ext4/dir.c:96
Read of size 1 at addr ffff888112785045 by task syz.2.19/5869

CPU: 0 UID: 0 PID: 5869 Comm: syz.2.19 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:4156 [inline]
 ext4_dir_entry_len fs/ext4/ext4.h:4183 [inline]
 __ext4_check_dir_entry+0x659/0xbe0 fs/ext4/dir.c:96
 ext4_find_dest_de+0x14e/0x6e0 fs/ext4/namei.c:2221
 ext4_add_dirent_to_inline+0xcc/0x410 fs/ext4/inline.c:984
 ext4_try_add_inline_entry+0x21e/0x8a0 fs/ext4/inline.c:1213
 __ext4_add_entry+0x385/0x3470 fs/ext4/namei.c:2552
 __ext4_link+0x498/0x720 fs/ext4/namei.c:3649
 ext4_link+0x1dc/0x2b0 fs/ext4/namei.c:3689
 vfs_link+0x491/0x650 fs/namei.c:5787
 ovl_do_link fs/overlayfs/overlayfs.h:233 [inline]
 ovl_copy_up_tmpfile fs/overlayfs/copy_up.c:891 [inline]
 ovl_do_copy_up fs/overlayfs/copy_up.c:986 [inline]
 ovl_copy_up_one fs/overlayfs/copy_up.c:1189 [inline]
 ovl_copy_up_flags+0x1c52/0x3930 fs/overlayfs/copy_up.c:1243
 ovl_open+0x13f/0x300 fs/overlayfs/file.c:211
 do_dentry_open+0x816/0x1380 fs/open.c:947
 vfs_open+0x3b/0x340 fs/open.c:1079
 dentry_open+0x61/0xa0 fs/open.c:1102
 ima_calc_file_hash+0x15f/0x890 security/integrity/ima/ima_crypto.c:269
 ima_collect_measurement+0x51b/0xa00 security/integrity/ima/ima_api.c:300
 process_measurement+0x1272/0x1c10 security/integrity/ima/ima_main.c:425
 ima_file_check+0xe1/0x130 security/integrity/ima/ima_main.c:685
 security_file_post_open+0xb3/0x260 security/security.c:2755
 do_open fs/namei.c:4702 [inline]
 path_openat+0x2e90/0x3830 fs/namei.c:4859
 do_file_open+0x23e/0x4a0 fs/namei.c:4888
 do_sys_openat2+0x115/0x200 fs/open.c:1395
 do_sys_open fs/open.c:1401 [inline]
 __do_sys_openat fs/open.c:1417 [inline]
 __se_sys_openat fs/open.c:1412 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1412
 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: 0033:0x7fae54f9ce59
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:00007fae55ddb028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fae55215fa0 RCX: 00007fae54f9ce59
RDX: 000000000000003f RSI: 0000200000000380 RDI: ffffffffffffff9c
RBP: 00007fae55032e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000186 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fae55216038 R14: 00007fae55215fa0 R15: 00007ffedd6a9a88
 </TASK>

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x112785
flags: 0x17ff00000000000(node=0|zone=2|lastcpupid=0x7ff)
page_type: f0(buddy)
raw: 017ff00000000000 ffffea000449e048 ffffea000449e2c8 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 26, tgid 26 (kworker/u9:0), ts 18747225753, free_ts 49527089310
 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+0x24ae/0x2530 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+0xb7/0x1c0 mm/kasan/shadow.c:424
 kasan_populate_vmalloc include/linux/kasan.h:580 [inline]
 alloc_vmap_area+0xd1a/0x1420 mm/vmalloc.c:2123
 __get_vm_area_node+0x1f2/0x300 mm/vmalloc.c:3226
 __vmalloc_node_range_noprof+0x358/0x1730 mm/vmalloc.c:4024
 __vmalloc_node_noprof+0xc2/0x100 mm/vmalloc.c:4124
 alloc_thread_stack_node kernel/fork.c:358 [inline]
 dup_task_struct+0x28e/0x850 kernel/fork.c:928
 copy_process+0x81b/0x42e0 kernel/fork.c:2109
 kernel_clone+0x2d7/0x940 kernel/fork.c:2745
 user_mode_thread+0x110/0x180 kernel/fork.c:2821
 call_usermodehelper_exec_work+0x5c/0x230 kernel/umh.c:171
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
page last free pid 5625 tgid 5625 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1397 [inline]
 __free_frozen_pages+0xc0d/0xd20 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+0xbd8/0x1420 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+0x783/0xb40 mm/vmalloc.c:2396
 drain_vmap_area_work+0x27/0x40 mm/vmalloc.c:2430
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
 kthread+0x388/0x470 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:
 ffff888112784f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888112784f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888112785000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                           ^
 ffff888112785080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888112785100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================


***

If these findings have caused you to resend the series or submit a
separate fix, please add the following tag to your commit message:
  Tested-by: syzbot@syzkaller.appspotmail.com

---
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