==================================================================
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 ffff888129230a00 by task syz.9.1597/4461
CPU: 1 PID: 4461 Comm: syz.9.1597 Tainted: G W syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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
mod_timer+0x1f/0x30 kernel/time/timer.c:1196
can_stat_update+0xb1a/0xbb0 net/can/proc.c:176
call_timer_fn+0x46/0x2a0 kernel/time/timer.c:1553
expire_timers kernel/time/timer.c:1604 [inline]
__run_timers+0x65b/0x9f0 kernel/time/timer.c:1875
run_timer_softirq+0x6a/0xf0 kernel/time/timer.c:1888
handle_softirqs+0x1d7/0x600 kernel/softirq.c:642
__do_softirq kernel/softirq.c:680 [inline]
invoke_softirq kernel/softirq.c:497 [inline]
__irq_exit_rcu+0x52/0xf0 kernel/softirq.c:729
irq_exit_rcu+0x9/0x10 kernel/softirq.c:741
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0xa9/0xc0 arch/x86/kernel/apic/apic.c:1118
asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:memset_erms+0xb/0x10 arch/x86/lib/memset_64.S:65
Code: 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 f3 aa <4c> 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 01 01
RSP: 0018:ffffc90000a27b90 EFLAGS: 00000202
RAX: ffffffff81468c00 RBX: 0000000000000018 RCX: 0000000000000000
RDX: 0000000000000018 RSI: 0000000000000000 RDI: ffffc90000a27c38
RBP: ffffc90000a27bb0 R08: ffffc90000a27c37 R09: ffffc90000a27c20
R10: dffffc0000000000 R11: fffff52000144f87 R12: 1ffff92000144f80
R13: dffffc0000000000 R14: 0000000000000000 R15: ffffc90000a27c20
restore_altstack+0x98/0x4c0 kernel/signal.c:4276
__ia32_sys_rt_sigreturn+0x639/0x730 arch/x86/kernel/signal.c:678
x64_sys_call+0x832/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:16
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
RIP: 0033:0x7fbd8e59aeb7
Code: 83 c8 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
RSP: 002b:00007fbd8f5220e8 EFLAGS: 00000246
RAX: 00000000000000ca RBX: 00007fbd8e815fa8 RCX: 00007fbd8e59aeb9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fbd8e815fa8
RBP: 00007fbd8e815fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbd8e816038 R14: 00007ffe4f206ba0 R15: 00007ffe4f206c88
Allocated by task 4308:
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 4308:
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 ffff888129230000
which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 2560 bytes inside of
8192-byte region [ffff888129230000, ffff888129232000)
The buggy address belongs to the physical page:
page:ffffea0004a48c00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x129230
head:ffffea0004a48c00 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head|zone=1)
raw: 4000000000010200 ffffea00049cda00 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 3896, tgid 3895 (syz.0.1389), ts 99253320089, free_ts 99226683617
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:5339 [inline]
ext4_fill_super+0x59fb/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_compound_page+0x99/0xd0 mm/page_alloc.c:859
destroy_large_folio+0x68/0xa0 mm/page_alloc.c:896
__folio_put_large mm/swap.c:113 [inline]
__folio_put+0xd1/0xe0 mm/swap.c:121
folio_put include/linux/mm.h:1442 [inline]
put_page include/linux/mm.h:1494 [inline]
__skb_frag_unref include/linux/skbuff.h:3478 [inline]
skb_release_data+0x47f/0x890 net/core/skbuff.c:788
skb_release_all net/core/skbuff.c:859 [inline]
__kfree_skb net/core/skbuff.c:873 [inline]
napi_consume_skb+0x121/0x2c0 net/core/skbuff.c:1112
free_old_xmit_skbs+0x10e/0x280 drivers/net/virtio_net.c:1639
virtnet_poll_tx+0x22b/0x540 drivers/net/virtio_net.c:1811
__napi_poll+0xd0/0x5e0 net/core/dev.c:6606
napi_poll net/core/dev.c:6673 [inline]
net_rx_action+0x4b6/0xac0 net/core/dev.c:6787
handle_softirqs+0x1d7/0x600 kernel/softirq.c:642
__do_softirq+0xb/0xd kernel/softirq.c:680
Memory state around the buggy address:
ffff888129230900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888129230980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888129230a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888129230a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888129230b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 PID: 4461 Comm: syz.9.1597 Tainted: G B W syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__queue_work+0x575/0xd30 kernel/workqueue.c:-1
Code: 39 2b 0f 84 b9 00 00 00 e8 18 47 29 00 4c 89 ff e8 10 31 b8 03 49 bc 00 00 00 00 00 fc ff df 4c 8b 6d d0 4c 89 e8 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 ef e8 cc 74 6e 00 49 8b 7d 00 e8 a3 2c
RSP: 0018:ffffc900001b0c70 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 000000007fffffff RCX: ffff88811e7d1440
RDX: 0000000000000100 RSI: 000000007fffffff RDI: 000000007fffffff
RBP: ffffc900001b0d08 R08: 0000000000000007 R09: fffffffffffffffb
R10: dffffc0000000000 R11: ffffed1025246139 R12: dffffc0000000000
R13: 0000000000000000 R14: ffff8881292309c8 R15: 0000000000000008
FS: 00007fbd8f5226c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f26e6a17dac CR3: 000000011bb48000 CR4: 00000000003506a0
Call Trace:
delayed_work_timer_fn+0x61/0x80 kernel/workqueue.c:1653
call_timer_fn+0x46/0x2a0 kernel/time/timer.c:1553
expire_timers kernel/time/timer.c:1599 [inline]
__run_timers+0x689/0x9f0 kernel/time/timer.c:1875
run_timer_softirq+0x6a/0xf0 kernel/time/timer.c:1888
handle_softirqs+0x1d7/0x600 kernel/softirq.c:642
__do_softirq kernel/softirq.c:680 [inline]
invoke_softirq kernel/softirq.c:497 [inline]
__irq_exit_rcu+0x52/0xf0 kernel/softirq.c:729
irq_exit_rcu+0x9/0x10 kernel/softirq.c:741
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0xa9/0xc0 arch/x86/kernel/apic/apic.c:1118
asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:memset_erms+0xb/0x10 arch/x86/lib/memset_64.S:65
Code: 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 f3 aa <4c> 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 01 01
RSP: 0018:ffffc90000a27b90 EFLAGS: 00000202
RAX: ffffffff81468c00 RBX: 0000000000000018 RCX: 0000000000000000
RDX: 0000000000000018 RSI: 0000000000000000 RDI: ffffc90000a27c38
RBP: ffffc90000a27bb0 R08: ffffc90000a27c37 R09: ffffc90000a27c20
R10: dffffc0000000000 R11: fffff52000144f87 R12: 1ffff92000144f80
R13: dffffc0000000000 R14: 0000000000000000 R15: ffffc90000a27c20
restore_altstack+0x98/0x4c0 kernel/signal.c:4276
__ia32_sys_rt_sigreturn+0x639/0x730 arch/x86/kernel/signal.c:678
x64_sys_call+0x832/0x9a0 arch/x86/include/generated/asm/syscalls_64.h:16
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
RIP: 0033:0x7fbd8e59aeb7
Code: 83 c8 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
RSP: 002b:00007fbd8f5220e8 EFLAGS: 00000246
RAX: 00000000000000ca RBX: 00007fbd8e815fa8 RCX: 00007fbd8e59aeb9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fbd8e815fa8
RBP: 00007fbd8e815fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbd8e816038 R14: 00007ffe4f206ba0 R15: 00007ffe4f206c88
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__queue_work+0x575/0xd30 kernel/workqueue.c:-1
Code: 39 2b 0f 84 b9 00 00 00 e8 18 47 29 00 4c 89 ff e8 10 31 b8 03 49 bc 00 00 00 00 00 fc ff df 4c 8b 6d d0 4c 89 e8 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 ef e8 cc 74 6e 00 49 8b 7d 00 e8 a3 2c
RSP: 0018:ffffc900001b0c70 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 000000007fffffff RCX: ffff88811e7d1440
RDX: 0000000000000100 RSI: 000000007fffffff RDI: 000000007fffffff
RBP: ffffc900001b0d08 R08: 0000000000000007 R09: fffffffffffffffb
R10: dffffc0000000000 R11: ffffed1025246139 R12: dffffc0000000000
R13: 0000000000000000 R14: ffff8881292309c8 R15: 0000000000000008
FS: 00007fbd8f5226c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f26e6a17dac CR3: 000000011bb48000 CR4: 00000000003506a0
----------------
Code disassembly (best guess):
0: 03 40 0f add 0xf(%rax),%eax
3: b6 f6 mov $0xf6,%dh
5: 48 b8 01 01 01 01 01 movabs $0x101010101010101,%rax
c: 01 01 01
f: 48 0f af c6 imul %rsi,%rax
13: f3 48 ab rep stos %rax,%es:(%rdi)
16: 89 d1 mov %edx,%ecx
18: f3 aa rep stos %al,%es:(%rdi)
1a: 4c 89 c8 mov %r9,%rax
1d: c3 ret
1e: 90 nop
1f: 49 89 f9 mov %rdi,%r9
22: 40 88 f0 mov %sil,%al
25: 48 89 d1 mov %rdx,%rcx
28: f3 aa rep stos %al,%es:(%rdi)
* 2a: 4c 89 c8 mov %r9,%rax <-- trapping instruction
2d: c3 ret
2e: 90 nop
2f: 49 89 fa mov %rdi,%r10
32: 40 0f b6 ce movzbl %sil,%ecx
36: 48 b8 01 01 01 01 01 movabs $0x101010101010101,%rax
3d: 01 01 01