==================================================================
BUG: KASAN: slab-use-after-free in lookup_noperm_common+0x407/0x430 fs/namei.c:3106
Read of size 4 at addr ffff8880619fc898 by task syz.4.1022/9561

CPU: 1 UID: 0 PID: 9561 Comm: syz.4.1022 Tainted: G             L      syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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
 lookup_noperm_common+0x407/0x430 fs/namei.c:3106
 simple_start_creating+0x9c/0x110 fs/libfs.c:2305
 debugfs_start_creating+0xca/0x1b0 fs/debugfs/inode.c:397
 debugfs_create_dir+0x24/0x350 fs/debugfs/inode.c:575
 i2c_device_probe+0x814/0xbf0 drivers/i2c/i2c-core-base.c:589
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x254/0xae0 drivers/base/dd.c:706
 __driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868
 driver_probe_device+0x4f/0x240 drivers/base/dd.c:898
 __device_attach_driver+0x270/0x410 drivers/base/dd.c:1026
 bus_for_each_drv+0x25b/0x2f0 drivers/base/bus.c:500
 __device_attach+0x2c7/0x450 drivers/base/dd.c:1098
 device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1153
 bus_probe_device+0x12d/0x220 drivers/base/bus.c:620
 device_add+0x7d7/0xb80 drivers/base/core.c:3776
 i2c_new_client_device+0xa29/0x1130 drivers/i2c/i2c-core-base.c:1020
 new_device_store+0x24b/0x530 drivers/i2c/i2c-core-base.c:1308
 kernfs_fop_write_iter+0x3a5/0x540 fs/kernfs/file.c:345
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x61e/0xbb0 fs/read_write.c:687
 ksys_write+0x156/0x270 fs/read_write.c:739
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc99f60e0d9
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> [  672.654494][ T9561] 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:00007fc99d866028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fc99f895fa0 RCX: 00007fc99f60e0d9
RDX: 0000000000000013 RSI: 0000200000000240 RDI: 0000000000000005
RBP: 00007fc99f6a5024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc99f896038 R14: 00007fc99f895fa0 R15: 00007ffdeb0ea0b8
 </TASK>

Allocated by task 998:
 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:4683 [inline]
 slab_alloc_node mm/slub.c:4996 [inline]
 kmem_cache_alloc_lru_noprof+0x35d/0x680 mm/slub.c:5029
 __d_alloc+0x37/0x6f0 fs/dcache.c:1907
 d_alloc+0x4b/0x190 fs/dcache.c:1986
 lookup_one_qstr_excl+0xd8/0x360 fs/namei.c:1806
 __start_dirop fs/namei.c:2920 [inline]
 start_dirop+0x5c/0x90 fs/namei.c:2942
 simple_start_creating+0xcc/0x110 fs/libfs.c:2308
 debugfs_start_creating+0xca/0x1b0 fs/debugfs/inode.c:397
 debugfs_create_dir+0x24/0x350 fs/debugfs/inode.c:575
 i2c_register_adapter+0xd3f/0x1510 drivers/i2c/i2c-core-base.c:1610
 ttusb_probe+0x10e5/0x2350 drivers/media/usb/ttusb-budget/dvb-ttusb-budget.c:1656
 usb_probe_interface+0x653/0xc60 drivers/usb/core/driver.c:396
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x254/0xae0 drivers/base/dd.c:706
 __driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868
 driver_probe_device+0x4f/0x240 drivers/base/dd.c:898
 __device_attach_driver+0x270/0x410 drivers/base/dd.c:1026
 bus_for_each_drv+0x25b/0x2f0 drivers/base/bus.c:500
 __device_attach+0x2c7/0x450 drivers/base/dd.c:1098
 device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1153
 bus_probe_device+0x12d/0x220 drivers/base/bus.c:620
 device_add+0x7d7/0xb80 drivers/base/core.c:3776
 usb_set_configuration+0x1ad8/0x2180 drivers/usb/core/message.c:2268
 usb_generic_driver_probe+0x8d/0x150 drivers/usb/core/generic.c:250
 usb_probe_device+0x1c3/0x3b0 drivers/usb/core/driver.c:291
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x254/0xae0 drivers/base/dd.c:706
 __driver_probe_device+0x1e8/0x360 drivers/base/dd.c:868
 driver_probe_device+0x4f/0x240 drivers/base/dd.c:898
 __device_attach_driver+0x270/0x410 drivers/base/dd.c:1026
 bus_for_each_drv+0x25b/0x2f0 drivers/base/bus.c:500
 __device_attach+0x2c7/0x450 drivers/base/dd.c:1098
 device_initial_probe+0xa1/0xd0 drivers/base/dd.c:1153
 bus_probe_device+0x12d/0x220 drivers/base/bus.c:620
 device_add+0x7d7/0xb80 drivers/base/core.c:3776
 usb_new_device+0x99a/0x1680 drivers/usb/core/hub.c:2703
 hub_port_connect drivers/usb/core/hub.c:5575 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5715 [inline]
 port_event drivers/usb/core/hub.c:5879 [inline]
 hub_event+0x28cf/0x4cf0 drivers/usb/core/hub.c:5961
 process_one_work kernel/workqueue.c:3387 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3470
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3551
 kthread+0x38b/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 28:
 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:2748 [inline]
 slab_free mm/slub.c:6499 [inline]
 kmem_cache_free+0x187/0x6d0 mm/slub.c:6626
 rcu_do_batch kernel/rcu/tree.c:2650 [inline]
 rcu_core kernel/rcu/tree.c:2919 [inline]
 rcu_cpu_kthread+0xb2c/0x1740 kernel/rcu/tree.c:3007
 smpboot_thread_fn+0x565/0xa70 kernel/smpboot.c:160
 kthread+0x38b/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
 __call_rcu_common kernel/rcu/tree.c:3181 [inline]
 call_rcu+0xee/0x8b0 kernel/rcu/tree.c:3301
 dentry_kill+0x4d3/0x880 fs/dcache.c:845
 finish_dput+0x1a/0x260 fs/dcache.c:1001
 debugfs_remove+0x5b/0x70 fs/debugfs/inode.c:784
 i2c_del_adapter+0x229/0x430 drivers/i2c/i2c-core-base.c:1830
 ttusb_disconnect+0x1e0/0x330 drivers/media/usb/ttusb-budget/dvb-ttusb-budget.c:1737
 usb_unbind_interface+0x295/0x9f0 drivers/usb/core/driver.c:458
 device_remove drivers/base/dd.c:618 [inline]
 __device_release_driver drivers/base/dd.c:1349 [inline]
 device_release_driver_internal+0x4f5/0x880 drivers/base/dd.c:1372
 bus_remove_device+0x449/0x560 drivers/base/bus.c:664
 device_del+0x528/0x8f0 drivers/base/core.c:3965
 usb_disable_device+0x3d4/0x8d0 drivers/usb/core/message.c:1478
 usb_disconnect+0x32d/0x990 drivers/usb/core/hub.c:2345
 hub_port_connect drivers/usb/core/hub.c:5415 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5715 [inline]
 port_event drivers/usb/core/hub.c:5879 [inline]
 hub_event+0x1bb7/0x4cf0 drivers/usb/core/hub.c:5961
 process_one_work kernel/workqueue.c:3387 [inline]
 process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3470
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3551
 kthread+0x38b/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 ffff8880619fc898
 which belongs to the cache dentry of size 376
The buggy address is located 0 bytes inside of
 freed 376-byte region [ffff8880619fc898, ffff8880619fca10)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8880619fcc08 pfn:0x619fc
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff8880619fdef1
flags: 0x80000000000240(workingset|head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000240 ffff88801b2c4500 ffffea0001036210 ffffea0000f92c10
raw: ffff8880619fcc08 000000020012000f 00000000f5000000 ffff8880619fdef1
head: 0080000000000240 ffff88801b2c4500 ffffea0001036210 ffffea0000f92c10
head: ffff8880619fcc08 000000020012000f 00000000f5000000 ffff8880619fdef1
head: 0080000000000001 ffffffffffffff81 00000000ffffffff 00000000ffffffff
head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000002
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Reclaimable, gfp_mask 0xd20d0(__GFP_RECLAIMABLE|__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5584, tgid 5584 (syz-executor), ts 106569926183
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1871
 prep_new_page mm/page_alloc.c:1879 [inline]
 get_page_from_freelist+0x2591/0x2600 mm/page_alloc.c:3943
 __alloc_frozen_pages_noprof+0x230/0x5c0 mm/page_alloc.c:5436
 alloc_slab_page mm/slub.c:3347 [inline]
 allocate_slab+0x7d/0x620 mm/slub.c:3462
 new_slab mm/slub.c:3513 [inline]
 refill_objects+0x2d8/0x350 mm/slub.c:7410
 refill_sheaf mm/slub.c:2885 [inline]
 __pcs_replace_empty_main+0x339/0x690 mm/slub.c:4774
 alloc_from_pcs mm/slub.c:4850 [inline]
 slab_alloc_node mm/slub.c:4984 [inline]
 kmem_cache_alloc_lru_noprof+0x455/0x680 mm/slub.c:5029
 __d_alloc+0x37/0x6f0 fs/dcache.c:1907
 d_alloc+0x4b/0x190 fs/dcache.c:1986
 lookup_one_qstr_excl+0xd8/0x360 fs/namei.c:1806
 __start_dirop fs/namei.c:2920 [inline]
 start_dirop+0x5c/0x90 fs/namei.c:2942
 simple_start_creating+0xcc/0x110 fs/libfs.c:2308
 debugfs_start_creating+0xca/0x1b0 fs/debugfs/inode.c:397
 __debugfs_create_file+0x6f/0x400 fs/debugfs/inode.c:431
 debugfs_create_file_short+0x3f/0x60 fs/debugfs/inode.c:474
 debugfs_hw_add+0x319/0x380 net/mac80211/debugfs.c:705
page_owner free stack trace missing

Memory state around the buggy address:
 ffff8880619fc780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880619fc800: 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc
>ffff8880619fc880: fc fc fc fa fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff8880619fc900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880619fc980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================