================================================================== BUG: KASAN: use-after-free in hlist_add_head include/linux/list.h:930 [inline] BUG: KASAN: use-after-free in enqueue_timer+0xae/0x480 kernel/time/timer.c:611 Write of size 8 at addr ffff8881464e8a00 by task kworker/0:1/19 CPU: 0 PID: 19 Comm: kworker/0:1 Tainted: G W syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 Workqueue: ipv6_addrconf addrconf_dad_work Call Trace: __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_add_head include/linux/list.h:930 [inline] enqueue_timer+0xae/0x480 kernel/time/timer.c:611 internal_add_timer kernel/time/timer.c:640 [inline] __mod_timer+0x84c/0xc00 kernel/time/timer.c:1137 add_timer+0x68/0x80 kernel/time/timer.c:1250 __queue_delayed_work+0x173/0x200 kernel/workqueue.c:1686 mod_delayed_work_on+0x74/0xe0 kernel/workqueue.c:1749 mod_delayed_work include/linux/workqueue.h:540 [inline] addrconf_mod_dad_work+0x7d/0x120 net/ipv6/addrconf.c:335 addrconf_dad_work+0x952/0x14d0 net/ipv6/addrconf.c:4237 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 Allocated by task 3640: 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+0x3c8/0xa20 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 3640: 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:1191 sock_ioctl+0x4bd/0x710 net/socket.c:1310 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:1191 sock_ioctl+0x4bd/0x710 net/socket.c:1310 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 ffff8881464e8000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 2560 bytes inside of 8192-byte region [ffff8881464e8000, ffff8881464ea000) The buggy address belongs to the physical page: page:ffffea0005193a00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1464e8 head:ffffea0005193a00 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head|zone=1) raw: 4000000000010200 ffffea0004795a00 dead000000000004 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 1340, tgid 1332 (syz.6.269), ts 74385448312, free_ts 70406729501 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x1f5/0x210 mm/page_alloc.c:2672 prep_new_page+0x1c/0x110 mm/page_alloc.c:2679 get_page_from_freelist+0x2d12/0x2d80 mm/page_alloc.c:4585 __alloc_pages+0x1fa/0x610 mm/page_alloc.c:5926 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_node_track_caller+0xa0/0x1e0 mm/slab_common.c:958 __do_krealloc mm/slab_common.c:1341 [inline] krealloc+0x6f/0x110 mm/slab_common.c:1374 copy_array kernel/bpf/verifier.c:955 [inline] copy_stack_state kernel/bpf/verifier.c:1009 [inline] copy_func_state kernel/bpf/verifier.c:1130 [inline] copy_verifier_state+0x6bb/0xab0 kernel/bpf/verifier.c:1166 push_stack+0x19b/0x4f0 kernel/bpf/verifier.c:1237 check_cond_jmp_op kernel/bpf/verifier.c:10491 [inline] do_check+0x963a/0xf070 kernel/bpf/verifier.c:12730 do_check_common+0x11ae/0x1950 kernel/bpf/verifier.c:14934 do_check_main kernel/bpf/verifier.c:14997 [inline] bpf_check+0x3f98/0x10d10 kernel/bpf/verifier.c:15574 page last free stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] free_pages_prepare mm/page_alloc.c:1580 [inline] free_pcp_prepare mm/page_alloc.c:1654 [inline] free_unref_page_prepare+0x7f8/0x800 mm/page_alloc.c:3620 free_unref_page_list+0x117/0x8c0 mm/page_alloc.c:3771 release_pages+0xc93/0xcf0 mm/swap.c:1053 __pagevec_release+0x71/0xe0 mm/swap.c:1073 pagevec_release include/linux/pagevec.h:71 [inline] folio_batch_release include/linux/pagevec.h:135 [inline] shmem_undo_range+0x574/0x1540 mm/shmem.c:951 shmem_truncate_range mm/shmem.c:1067 [inline] shmem_evict_inode+0x255/0xa50 mm/shmem.c:1176 evict+0x4d7/0x8f0 fs/inode.c:708 iput_final fs/inode.c:1844 [inline] iput+0x620/0x670 fs/inode.c:1870 dentry_unlink_inode+0x33d/0x3f0 fs/dcache.c:405 __dentry_kill+0x460/0x670 fs/dcache.c:611 dentry_kill+0xc0/0x2a0 fs/dcache.c:-1 dput+0x42/0x80 fs/dcache.c:918 __fput+0x5be/0x8f0 fs/file_table.c:328 ____fput+0x15/0x20 fs/file_table.c:348 task_work_run+0x1e1/0x250 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0x9b/0xb0 kernel/entry/common.c:177 Memory state around the buggy address: ffff8881464e8900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881464e8980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881464e8a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881464e8a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881464e8b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb 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