syzbot

GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog
bridge0: received packet on gretap1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on gretap1 with own address as source address (addr:be:a9:4b:92:2e:94, vlan:0)
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (0 ticks this GP) idle=5294/1/0x4000000000000000 softirq=33156/33156 fqs=0
rcu: 	(detected by 1, t=10502 jiffies, g=34305, q=276 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 9962 Comm: syz.2.1280 Not tainted 6.14.0-rc1-syzkaller-00028-g5c8c229261f1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4875 [inline]
RIP: 0010:__lock_acquire+0x99f/0x2100 kernel/locking/lockdep.c:5178
Code: 81 c3 c6 00 00 00 48 89 d8 48 c1 e8 03 0f b6 04 10 84 c0 0f 85 a5 00 00 00 80 3b 02 74 30 49 ff c6 48 8b 44 24 30 0f b6 04 10 <84> c0 75 6a 48 8b 04 24 48 63 00 49 83 c7 28 49 83 c5 28 41 ff c4
RSP: 0018:ffffc900000078f0 EFLAGS: 00000003
RAX: 0000000000000000 RBX: ffffffff93c76c26 RCX: 0000000000000002
RDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffffffff942f9848
RBP: 0000000000000002 R08: ffffffff942f984f R09: 1ffffffff285f309
R10: dffffc0000000000 R11: fffffbfff285f30a R12: 0000000000000003
R13: ffff8880778ee588 R14: 0000000000000004 R15: ffff8880778ee588
FS:  000055555d43f500(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c362554 CR3: 0000000027c40000 CR4: 0000000000350ef0
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
 debug_object_activate+0x17f/0x580 lib/debugobjects.c:818
 debug_hrtimer_activate kernel/time/hrtimer.c:455 [inline]
 debug_activate kernel/time/hrtimer.c:496 [inline]
 enqueue_hrtimer+0x30/0x3c0 kernel/time/hrtimer.c:1100
 __run_hrtimer kernel/time/hrtimer.c:1818 [inline]
 __hrtimer_run_queues+0x6cb/0xd30 kernel/time/hrtimer.c:1865
 hrtimer_interrupt+0x403/0xa40 kernel/time/hrtimer.c:1927
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline]
 __sysvec_apic_timer_interrupt+0x112/0x420 arch/x86/kernel/apic/apic.c:1055
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1049
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire+0x264/0x550 kernel/locking/lockdep.c:5855
Code: 2b 00 74 08 4c 89 f7 e8 fa 3b 8b 00 f6 44 24 61 02 0f 85 85 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25
RSP: 0018:ffffc90003e978c0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff920007d2f24 RCX: ffff8880778ee4e8
RDX: dffffc0000000000 RSI: ffffffff8c0ab8e0 RDI: ffffffff8c608a00
RBP: ffffc90003e97a08 R08: ffffffff96b9987f R09: 1ffffffff2d7330f
R10: dffffc0000000000 R11: fffffbfff2d73310 R12: 1ffff920007d2f20
R13: dffffc0000000000 R14: ffffc90003e97920 R15: 0000000000000246
 __mutex_lock_common kernel/locking/mutex.c:585 [inline]
 __mutex_lock+0x19c/0x1010 kernel/locking/mutex.c:730
 rtnl_net_lock include/linux/rtnetlink.h:129 [inline]
 unregister_netdev+0x17/0x30 net/core/dev.c:11871
 sixpack_close+0x1df/0x280 drivers/net/hamradio/6pack.c:661
 tty_ldisc_kill+0xa3/0x1a0 drivers/tty/tty_ldisc.c:613
 tty_ldisc_release+0x1a1/0x200 drivers/tty/tty_ldisc.c:781
 tty_release_struct+0x2b/0xe0 drivers/tty/tty_io.c:1690
 tty_release+0xd06/0x12c0 drivers/tty/tty_io.c:1861
 __fput+0x3eb/0x9f0 fs/file_table.c:448
 task_work_run+0x251/0x310 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x13f/0x340 kernel/entry/common.c:218
 do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9dc5f8cde9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffce3c011a8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 0000000000042e24 RCX: 00007f9dc5f8cde9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f9dc61a7ba0 R08: 0000000000000001 R09: 00000004e3c0149f
R10: 00007f9dc5e00000 R11: 0000000000000246 R12: 00007f9dc61a5fac
R13: 00007f9dc61a5fa0 R14: ffffffffffffffff R15: 00007ffce3c012c0
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g34305 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=21624
rcu: rcu_preempt kthread starved for 10502 jiffies! g34305 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:I stack:26104 pid:17    tgid:17    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5377 [inline]
 __schedule+0x190e/0x4c90 kernel/sched/core.c:6764
 __schedule_loop kernel/sched/core.c:6841 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6856
 schedule_timeout+0x15a/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2024
 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2226
 kthread+0x7ab/0x920 kernel/kthread.c:464
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>