[v6.6] WARNING in call_timer_fn

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: c2603c511feb Linux 6.6.93
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1793c370580000
kernel config: https://syzkaller.appspot.com/x/.config?x=486bade17c8c30b9
dashboard link: https://syzkaller.appspot.com/bug?extid=4ec2f23cfdd215d89b91
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/5819843271d0/disk-c2603c51.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/113f268f936d/vmlinux-c2603c51.xz
kernel image: https://storage.googleapis.com/syzbot-assets/493dd7e2863f/bzImage-c2603c51.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4ec2f2...@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 1 PID: 10709 at kernel/workqueue.c:1726 is_chained_work kernel/workqueue.c:1672 [inline]
WARNING: CPU: 1 PID: 10709 at kernel/workqueue.c:1726 __queue_work+0xd49/0x1020 kernel/workqueue.c:1725
Modules linked in:
CPU: 1 PID: 10709 Comm: syz-executor Not tainted 6.6.93-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:__queue_work+0xd49/0x1020 kernel/workqueue.c:1725
Code: 4c 89 f7 48 89 de 89 e9 e8 d4 e3 00 00 48 8b 5c 24 10 e9 10 ff ff ff e8 85 39 2f 00 eb 0c e8 7e 39 2f 00 eb 05 e8 77 39 2f 00 <0f> 0b 48 83 c4 78 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 61 39 2f 00
RSP: 0018:ffffc900001f0b10 EFLAGS: 00010046
RAX: ffffffff81565d5b RBX: 0000000000000100 RCX: ffff88807d5c9e00
RDX: 0000000000000100 RSI: 0000000000000100 RDI: 0000000000000000
RBP: ffff888024a5edc0 R08: ffffffff8e49a76f R09: 1ffffffff1c934ed
R10: dffffc0000000000 R11: fffffbfff1c934ee R12: 0000000000000008
R13: dffffc0000000000 R14: 0000000000000001 R15: ffff888024a5ec00
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc40a87a40 CR3: 000000000cb30000 CR4: 00000000003506e0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
<IRQ>
call_timer_fn+0x16e/0x530 kernel/time/timer.c:1700
expire_timers kernel/time/timer.c:1746 [inline]
__run_timers+0x558/0x7d0 kernel/time/timer.c:2022
run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2035
handle_softirqs+0x280/0x820 kernel/softirq.c:578
__do_softirq kernel/softirq.c:612 [inline]
invoke_softirq kernel/softirq.c:452 [inline]
__irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:lock_acquire+0x1f2/0x410 kernel/locking/lockdep.c:5758
Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f5 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 66 43 c7 44 3c 09 00 00 43 c6 44 3c 0b 00
RSP: 0018:ffffc90003247760 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 556544001dd08500
RDX: 0000000000000001 RSI: ffffffff8aaac440 RDI: ffffffff8afc6780
RBP: ffffc90003247868 R08: dffffc0000000000 R09: 1ffffffff26c46e7
R10: dffffc0000000000 R11: fffffbfff26c46e8 R12: 1ffff92000648ef8
R13: ffff888024a5ed38 R14: 0000000000000246 R15: dffffc0000000000
touch_wq_lockdep_map kernel/workqueue.c:3138 [inline]
__flush_workqueue+0x141/0x1380 kernel/workqueue.c:3168
drain_workqueue+0xd3/0x380 kernel/workqueue.c:3332
hci_dev_close_sync+0x4b9/0xfb0 net/bluetooth/hci_sync.c:5203
hci_dev_do_close net/bluetooth/hci_core.c:505 [inline]
hci_unregister_dev+0x206/0x500 net/bluetooth/hci_core.c:2684
vhci_release+0x83/0xd0 drivers/bluetooth/hci_vhci.c:666
__fput+0x234/0x970 fs/file_table.c:384
task_work_run+0x1ce/0x250 kernel/task_work.c:239
exit_task_work include/linux/task_work.h:43 [inline]
do_exit+0x903/0x23c0 kernel/exit.c:874
do_group_exit+0x21b/0x2d0 kernel/exit.c:1023
__do_sys_exit_group kernel/exit.c:1034 [inline]
__se_sys_exit_group kernel/exit.c:1032 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1032
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fa5d218e929
Code: Unable to access opcode bytes at 0x7fa5d218e8ff.
RSP: 002b:00007ffc40a89c18 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fa5d218e929
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000043
RBP: 00007fa5d21ee8f0 R08: 00007ffc40a879b7 R09: 0000000000000003
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 0000000000000003 R14: 00000000ffffffff R15: 00007ffc40a89dd0
</TASK>
----------------
Code disassembly (best guess):
0: 00 9c 8f 84 24 80 00 add %bl,0x802484(%rdi,%rcx,4)
7: 00 00 add %al,(%rax)
9: f6 84 24 81 00 00 00 testb $0x2,0x81(%rsp)
10: 02
11: 0f 85 f5 00 00 00 jne 0x10c
17: 41 f7 c6 00 02 00 00 test $0x200,%r14d
1e: 74 01 je 0x21
20: fb sti
21: 48 c7 44 24 60 0e 36 movq $0x45e0360e,0x60(%rsp)
28: e0 45
* 2a: 4b c7 04 3c 00 00 00 movq $0x0,(%r12,%r15,1) <-- trapping instruction
31: 00
32: 66 43 c7 44 3c 09 00 movw $0x0,0x9(%r12,%r15,1)
39: 00
3a: 43 c6 44 3c 0b 00 movb $0x0,0xb(%r12,%r15,1)


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 6282921b6825 Linux 6.6.94
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=11cac182580000
kernel config: https://syzkaller.appspot.com/x/.config?x=96da6b2210cda427

dashboard link: https://syzkaller.appspot.com/bug?extid=4ec2f23cfdd215d89b91
compiler: Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12b0330c580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/bb8094930023/disk-6282921b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6b695542f7a7/vmlinux-6282921b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f899d5f4fdd2/bzImage-6282921b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4ec2f2...@syzkaller.appspotmail.com

------------[ cut here ]------------

WARNING: CPU: 1 PID: 15020 at kernel/workqueue.c:1726 is_chained_work kernel/workqueue.c:1672 [inline]
WARNING: CPU: 1 PID: 15020 at kernel/workqueue.c:1726 __queue_work+0xd49/0x1020 kernel/workqueue.c:1725
Modules linked in:
CPU: 1 PID: 15020 Comm: syz-executor Not tainted 6.6.94-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:__queue_work+0xd49/0x1020 kernel/workqueue.c:1725

Code: 4c 89 f7 48 89 de 89 e9 e8 d4 e3 00 00 48 8b 5c 24 10 e9 10 ff ff ff e8 75 38 2f 00 eb 0c e8 6e 38 2f 00 eb 05 e8 67 38 2f 00 <0f> 0b 48 83 c4 78 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 51 38 2f 00

RSP: 0018:ffffc900001f0b10 EFLAGS: 00010046

RAX: ffffffff81565d5b RBX: 0000000000000100 RCX: ffff88807e4a9e00

RDX: 0000000000000100 RSI: 0000000000000100 RDI: 0000000000000000

RBP: ffff888024a8a9c0 R08: ffffffff8e49ab2f R09: 1ffffffff1c93565
R10: dffffc0000000000 R11: fffffbfff1c93566 R12: 0000000000000008
R13: dffffc0000000000 R14: 0000000000000001 R15: ffff888024a8a800
FS: 0000555567b98500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007f206b750ff8 CR3: 000000005e4e1000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Call Trace:
<IRQ>
call_timer_fn+0x16e/0x530 kernel/time/timer.c:1700
expire_timers kernel/time/timer.c:1746 [inline]
__run_timers+0x558/0x7d0 kernel/time/timer.c:2022
run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2035
handle_softirqs+0x280/0x820 kernel/softirq.c:578
__do_softirq kernel/softirq.c:612 [inline]
invoke_softirq kernel/softirq.c:452 [inline]
__irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:lock_acquire+0x1f2/0x410 kernel/locking/lockdep.c:5758
Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f5 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 66 43 c7 44 3c 09 00 00 43 c6 44 3c 0b 00

RSP: 0018:ffffc900050f7120 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: f88096dbe15eb200
RDX: 0000000000000000 RSI: ffffffff8aaac440 RDI: ffffffff8afc6900
RBP: ffffc900050f7240 R08: dffffc0000000000 R09: 1ffffffff21b0aa5
R10: dffffc0000000000 R11: fffffbfff21b0aa6 R12: 1ffff92000a1ee30
R13: ffff8880b8f3b8b8 R14: 0000000000000246 R15: dffffc0000000000
local_lock_acquire include/linux/local_lock_internal.h:29 [inline]
__radix_tree_preload+0x9b/0x880 lib/radix-tree.c:334
idr_preload+0x1d/0x210 lib/radix-tree.c:1471
__kernfs_new_node+0xfd/0x7e0 fs/kernfs/dir.c:628
kernfs_new_node+0x14c/0x260 fs/kernfs/dir.c:700
__kernfs_create_file+0x4b/0x2e0 fs/kernfs/file.c:1050
sysfs_add_file_mode_ns+0x238/0x300 fs/sysfs/file.c:294
create_files fs/sysfs/group.c:64 [inline]
internal_create_group+0x428/0xd00 fs/sysfs/group.c:152
internal_create_groups fs/sysfs/group.c:192 [inline]
sysfs_create_groups+0x59/0x120 fs/sysfs/group.c:218
device_add_groups drivers/base/core.c:2785 [inline]
device_add_attrs+0x1b2/0x810 drivers/base/core.c:2905
device_add+0x528/0xc20 drivers/base/core.c:3637
netdev_register_kobject+0x17a/0x310 net/core/net-sysfs.c:2042
register_netdevice+0x128f/0x1ae0 net/core/dev.c:10268
__ip_tunnel_create+0x3b4/0x4c0 net/ipv4/ip_tunnel.c:267
ip_tunnel_init_net+0x2c3/0x770 net/ipv4/ip_tunnel.c:1118
ops_init+0x397/0x640 net/core/net_namespace.c:139
setup_net+0x3a5/0xa00 net/core/net_namespace.c:343
copy_net_ns+0x36d/0x5e0 net/core/net_namespace.c:520
create_new_namespaces+0x3d3/0x6f0 kernel/nsproxy.c:110
unshare_nsproxy_namespaces+0x11a/0x160 kernel/nsproxy.c:228
ksys_unshare+0x4c0/0x890 kernel/fork.c:3439
__do_sys_unshare kernel/fork.c:3510 [inline]
__se_sys_unshare kernel/fork.c:3508 [inline]
__x64_sys_unshare+0x38/0x40 kernel/fork.c:3508

do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2

RIP: 0033:0x7fbe38d90127
Code: 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 10 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffcee9532e8 EFLAGS: 00000206 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fbe38d90127
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000
RBP: 00007ffcee953350 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 00007ffcee953350
R13: 00007ffcee953358 R14: 0000000000000009 R15: 0000000000000000

</TASK>
----------------
Code disassembly (best guess):
0: 00 9c 8f 84 24 80 00 add %bl,0x802484(%rdi,%rcx,4)
7: 00 00 add %al,(%rax)
9: f6 84 24 81 00 00 00 testb $0x2,0x81(%rsp)
10: 02
11: 0f 85 f5 00 00 00 jne 0x10c
17: 41 f7 c6 00 02 00 00 test $0x200,%r14d
1e: 74 01 je 0x21
20: fb sti
21: 48 c7 44 24 60 0e 36 movq $0x45e0360e,0x60(%rsp)
28: e0 45
* 2a: 4b c7 04 3c 00 00 00 movq $0x0,(%r12,%r15,1) <-- trapping instruction
31: 00
32: 66 43 c7 44 3c 09 00 movw $0x0,0x9(%r12,%r15,1)
39: 00
3a: 43 c6 44 3c 0b 00 movb $0x0,0xb(%r12,%r15,1)


---

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.