syzbot

bridge0: port 1(bridge_slave_0) entered disabled state
device veth1_macvtap left promiscuous mode
device veth0_vlan left promiscuous mode
==================================================================
BUG: KASAN: use-after-free in __hlist_del include/linux/list.h:884 [inline]
BUG: KASAN: use-after-free in detach_timer kernel/time/timer.c:886 [inline]
BUG: KASAN: use-after-free in detach_if_pending+0x156/0x300 kernel/time/timer.c:905
Write of size 8 at addr ffff8881274dc9f8 by task kworker/u4:0/8

CPU: 0 PID: 8 Comm: kworker/u4:0 Tainted: G        W          syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: netns cleanup_net

Call Trace:
 <TASK>
 __dump_stack+0x21/0x24 lib/dump_stack.c:88
 dump_stack_lvl+0x110/0x170 lib/dump_stack.c:106
 print_address_description+0x71/0x200 mm/kasan/report.c:316
 print_report+0x4a/0x60 mm/kasan/report.c:420
 kasan_report+0x122/0x150 mm/kasan/report.c:524
 __asan_report_store8_noabort+0x17/0x20 mm/kasan/report_generic.c:356
 __hlist_del include/linux/list.h:884 [inline]
 detach_timer kernel/time/timer.c:886 [inline]
 detach_if_pending+0x156/0x300 kernel/time/timer.c:905
 try_to_del_timer_sync kernel/time/timer.c:1365 [inline]
 del_timer_sync+0x136/0x1a0 kernel/time/timer.c:1515
 wg_timers_stop+0x49/0x60 drivers/net/wireguard/timers.c:241
 wg_stop+0x81/0x5d0 drivers/net/wireguard/device.c:123
 __dev_close_many+0x293/0x360 net/core/dev.c:1580
 dev_close_many+0x21e/0x4d0 net/core/dev.c:1605
 unregister_netdevice_many+0x44f/0x18e0 net/core/dev.c:10941
 default_device_exit_batch+0x9dc/0xa70 net/core/dev.c:11480
 ops_exit_list net/core/net_namespace.c:177 [inline]
 cleanup_net+0x635/0xb10 net/core/net_namespace.c:604
 process_one_work+0x71f/0xc40 kernel/workqueue.c:2302
 worker_thread+0xa29/0x11e0 kernel/workqueue.c:2449
 kthread+0x281/0x320 kernel/kthread.c:386
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

Allocated by task 7348:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 kasan_save_alloc_info+0x25/0x30 mm/kasan/generic.c:505
 ____kasan_kmalloc mm/kasan/common.c:380 [inline]
 __kasan_kmalloc+0x95/0xb0 mm/kasan/common.c:389
 kasan_kmalloc include/linux/kasan.h:212 [inline]
 __do_kmalloc_node mm/slab_common.c:938 [inline]
 __kmalloc+0xb1/0x1e0 mm/slab_common.c:951
 kmalloc include/linux/slab.h:568 [inline]
 kzalloc include/linux/slab.h:699 [inline]
 hci_alloc_dev_priv+0x27/0x1bd0 net/bluetooth/hci_core.c:2433
 hci_alloc_dev include/net/bluetooth/hci_core.h:1505 [inline]
 hci_uart_register_dev drivers/bluetooth/hci_ldisc.c:641 [inline]
 hci_uart_set_proto drivers/bluetooth/hci_ldisc.c:719 [inline]
 hci_uart_tty_ioctl+0x3d6/0xa20 drivers/bluetooth/hci_ldisc.c:774
 tty_ioctl+0x8ef/0xc60 drivers/tty/tty_io.c:2785
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0x12f/0x1b0 fs/ioctl.c:856
 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:856
 x64_sys_call+0x58b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Freed by task 7348:
 kasan_save_stack mm/kasan/common.c:46 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
 kasan_save_free_info+0x31/0x50 mm/kasan/generic.c:516
 ____kasan_slab_free+0x132/0x180 mm/kasan/common.c:242
 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:250
 kasan_slab_free include/linux/kasan.h:178 [inline]
 slab_free_hook mm/slub.c:1750 [inline]
 slab_free_freelist_hook+0xc2/0x190 mm/slub.c:1776
 slab_free mm/slub.c:3712 [inline]
 __kmem_cache_free+0xb7/0x1b0 mm/slub.c:3728
 kfree+0x6f/0xf0 mm/slab_common.c:990
 hci_release_dev+0x12a3/0x13b0 net/bluetooth/hci_core.c:2761
 bt_host_release+0x82/0x90 net/bluetooth/hci_sysfs.c:85
 device_release+0xa4/0x1d0 drivers/base/core.c:-1
 kobject_cleanup lib/kobject.c:681 [inline]
 kobject_release lib/kobject.c:712 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x19d/0x280 lib/kobject.c:729
 put_device+0x1f/0x30 drivers/base/core.c:3806
 hci_dev_put include/net/bluetooth/hci_core.h:1465 [inline]
 hci_dev_cmd+0x279/0x740 net/bluetooth/hci_core.c:795
 hci_sock_ioctl+0x41e/0x7f0 net/bluetooth/hci_sock.c:1096
 sock_do_ioctl+0x114/0x330 net/socket.c:1194
 sock_ioctl+0x4ca/0x720 net/socket.c:1311
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0x12f/0x1b0 fs/ioctl.c:856
 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:856
 x64_sys_call+0x58b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Last potentially related work creation:
 kasan_save_stack+0x3a/0x60 mm/kasan/common.c:46
 __kasan_record_aux_stack+0xb6/0xc0 mm/kasan/generic.c:486
 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:496
 insert_work+0x51/0x300 kernel/workqueue.c:1368
 __queue_work+0x9b1/0xd30 kernel/workqueue.c:1527
 queue_work_on+0xde/0x150 kernel/workqueue.c:1555
 queue_work include/linux/workqueue.h:510 [inline]
 hci_cmd_sync_run net/bluetooth/hci_sync.c:140 [inline]
 __hci_cmd_sync_sk+0xa7f/0xd30 net/bluetooth/hci_sync.c:162
 __hci_cmd_sync_status_sk net/bluetooth/hci_sync.c:253 [inline]
 __hci_cmd_sync_status net/bluetooth/hci_sync.c:277 [inline]
 hci_cmd_sync_status+0x53/0x120 net/bluetooth/hci_sync.c:288
 hci_dev_cmd+0x648/0x740 net/bluetooth/hci_core.c:-1
 hci_sock_ioctl+0x41e/0x7f0 net/bluetooth/hci_sock.c:1096
 sock_do_ioctl+0x114/0x330 net/socket.c:1194
 sock_ioctl+0x4ca/0x720 net/socket.c:1311
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0x12f/0x1b0 fs/ioctl.c:856
 __x64_sys_ioctl+0x7b/0x90 fs/ioctl.c:856
 x64_sys_call+0x58b/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Second to last potentially related work creation:
 kasan_save_stack+0x3a/0x60 mm/kasan/common.c:46
 __kasan_record_aux_stack+0xb6/0xc0 mm/kasan/generic.c:486
 kasan_record_aux_stack_noalloc+0xb/0x10 mm/kasan/generic.c:496
 insert_work+0x51/0x300 kernel/workqueue.c:1368
 __queue_work+0x9b1/0xd30 kernel/workqueue.c:1527
 queue_work_on+0xde/0x150 kernel/workqueue.c:1555
 queue_work include/linux/workqueue.h:510 [inline]
 hci_cmd_timeout+0x191/0x200 net/bluetooth/hci_core.c:1468
 process_one_work+0x71f/0xc40 kernel/workqueue.c:2302
 worker_thread+0xa29/0x11e0 kernel/workqueue.c:2449
 kthread+0x281/0x320 kernel/kthread.c:386
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

The buggy address belongs to the object at ffff8881274dc000
 which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 2552 bytes inside of
 8192-byte region [ffff8881274dc000, ffff8881274de000)

The buggy address belongs to the physical page:
page:ffffea00049d3600 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1274d8
head:ffffea00049d3600 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head|zone=1)
raw: 4000000000010200 ffffea0004713a00 dead000000000005 ffff888100043500
raw: 0000000000000000 0000000000020002 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 5933, tgid 5932 (syz.9.2342), ts 114609611091, free_ts 114600342283
 set_page_owner include/linux/page_owner.h:33 [inline]
 post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2643
 prep_new_page+0x1c/0x110 mm/page_alloc.c:2650
 get_page_from_freelist+0x2d12/0x2d80 mm/page_alloc.c:4554
 __alloc_pages+0x1d9/0x480 mm/page_alloc.c:5868
 alloc_slab_page+0x6e/0xf0 include/linux/gfp.h:-1
 allocate_slab mm/slub.c:1967 [inline]
 new_slab+0x98/0x3d0 mm/slub.c:2020
 ___slab_alloc+0x6bd/0xb20 mm/slub.c:3177
 __slab_alloc+0x5e/0xa0 mm/slub.c:3263
 slab_alloc_node mm/slub.c:3348 [inline]
 __kmem_cache_alloc_node+0x203/0x2c0 mm/slub.c:3423
 __do_kmalloc_node mm/slab_common.c:937 [inline]
 __kmalloc+0xa1/0x1e0 mm/slab_common.c:951
 kmalloc_array include/linux/slab.h:615 [inline]
 mb_cache_create+0x187/0x5a0 fs/mbcache.c:370
 ext4_xattr_create_cache+0x13/0x20 fs/ext4/xattr.c:3172
 __ext4_fill_super fs/ext4/super.c:5331 [inline]
 ext4_fill_super+0x53a8/0x7a40 fs/ext4/super.c:5650
 get_tree_bdev+0x447/0x690 fs/super.c:1368
 ext4_get_tree+0x1c/0x20 fs/ext4/super.c:5680
 vfs_get_tree+0x9a/0x270 fs/super.c:1575
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:26 [inline]
 free_pages_prepare mm/page_alloc.c:1551 [inline]
 free_pcp_prepare mm/page_alloc.c:1625 [inline]
 free_unref_page_prepare+0x742/0x750 mm/page_alloc.c:3589
 free_unref_page+0x95/0x540 mm/page_alloc.c:3687
 free_the_page mm/page_alloc.c:836 [inline]
 __free_pages+0x67/0x100 mm/page_alloc.c:5957
 __free_slab+0xca/0x1a0 mm/slub.c:2044
 free_slab mm/slub.c:2059 [inline]
 discard_slab mm/slub.c:2065 [inline]
 __unfreeze_partials+0x160/0x190 mm/slub.c:2614
 put_cpu_partial+0xa9/0x100 mm/slub.c:2690
 __slab_free+0x1c4/0x280 mm/slub.c:3589
 do_slab_free mm/slub.c:3666 [inline]
 ___cache_free+0xbf/0xd0 mm/slub.c:3722
 qlink_free mm/kasan/quarantine.c:168 [inline]
 qlist_free_all+0xc6/0x140 mm/kasan/quarantine.c:187
 kasan_quarantine_reduce+0x14a/0x170 mm/kasan/quarantine.c:294
 __kasan_slab_alloc+0x24/0x80 mm/kasan/common.c:311
 kasan_slab_alloc include/linux/kasan.h:202 [inline]
 slab_post_alloc_hook+0x4f/0x2d0 mm/slab.h:768
 slab_alloc_node mm/slub.c:3382 [inline]
 slab_alloc mm/slub.c:3392 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3399 [inline]
 kmem_cache_alloc+0x16e/0x330 mm/slub.c:3408
 getname_flags+0xb9/0x500 fs/namei.c:139
 getname+0x19/0x20 fs/namei.c:218
 do_sys_openat2+0xeb/0x810 fs/open.c:1337

Memory state around the buggy address:
 ffff8881274dc880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881274dc900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881274dc980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                                ^
 ffff8881274dca00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881274dca80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================