syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 ticks this GP) idle=46a4/1/0x4000000000000000 softirq=109209/109209 fqs=0
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P9669/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=87057, q=629 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 22726 Comm: syz-executor Not tainted 6.16.0-syzkaller-12256-g561c80369df0 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:mark_lock+0x22/0x610 kernel/locking/lockdep.c:4714
Code: 90 90 90 90 90 90 90 90 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 f0 48 83 ec 70 65 48 8b 05 3b 95 3e 12 48 89 44 24 68 <31> c0 83 fa 09 0f 87 8d 00 00 00 49 89 ff 49 89 f4 89 d3 83 fa 08
RSP: 0018:ffffc90000007940 EFLAGS: 00000082
RAX: a03e22c21f1f1100 RBX: ffff88807b795370 RCX: ffffffff95dd4e88
RDX: 0000000000000000 RSI: ffff88807b7953e8 RDI: ffff88807b794880
RBP: ffffc900000079e0 R08: 0000000000080000 R09: 0000000000000001
R10: 0000000000000078 R11: 0000000000000001 R12: ffff88807b7953e8
R13: ffff88807b794880 R14: 0000000000000003 R15: 0000000000000002
FS:  000055556eb52500(0000) GS:ffff8881246bd000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000027b030 CR3: 0000000067a52000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 mark_usage kernel/locking/lockdep.c:4639 [inline]
 __lock_acquire+0xac4/0x1ce0 kernel/locking/lockdep.c:5191
 lock_acquire kernel/locking/lockdep.c:5868 [inline]
 lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
 debug_object_deactivate+0x135/0x3a0 lib/debugobjects.c:873
 debug_hrtimer_deactivate kernel/time/hrtimer.c:450 [inline]
 debug_deactivate kernel/time/hrtimer.c:490 [inline]
 __run_hrtimer kernel/time/hrtimer.c:1729 [inline]
 __hrtimer_run_queues+0x46f/0xad0 kernel/time/hrtimer.c:1825
 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1887
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
 __sysvec_apic_timer_interrupt+0x10b/0x3f0 arch/x86/kernel/apic/apic.c:1056
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0x52/0xc0 arch/x86/kernel/apic/apic.c:1050
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:202
Code: 90 f3 0f 1e fa 53 48 8b 74 24 08 48 89 fb 48 83 c7 18 e8 aa ca 01 f6 48 89 df e8 92 1e 02 f6 e8 3d 82 2d f6 fb bf 01 00 00 00 <e8> 12 1c f2 f5 65 8b 05 8b 38 40 08 85 c0 74 06 5b c3 cc cc cc cc
RSP: 0018:ffffc90000007eb0 EFLAGS: 00000202
RAX: 000000000001851a RBX: ffff8880b8425b00 RCX: 0000000000000002
RDX: 0000000000000000 RSI: ffffffff8de4f125 RDI: 0000000000000001
RBP: 1ffff92000000fd8 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff90ab3597 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000100 R14: 0000000000000000 R15: ffffffff8e20c0c8
 __run_timer_base kernel/time/timer.c:2385 [inline]
 __run_timer_base kernel/time/timer.c:2376 [inline]
 run_timer_base+0x11c/0x190 kernel/time/timer.c:2393
 run_timer_softirq+0x1a/0x40 kernel/time/timer.c:2403
 handle_softirqs+0x216/0x8e0 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0x109/0x170 kernel/softirq.c:680
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1050
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:rcu_is_watching+0x0/0xc0 kernel/rcu/tree.c:747
Code: b7 5c 8e e8 e2 6f 76 03 e9 51 ff ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 55 53 65 ff 05 f3 7c 35 12 e8 5e a1 f2 09 48 c7 c3 a8
RSP: 0018:ffffc9001d80f150 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffffffff8f7ad4e0 RCX: ffffffff81860366
RDX: ffff88807b794880 RSI: ffffffff81860374 RDI: 0000000000000001
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 00000000ffffffd7
R13: dffffc0000000000 R14: ffffffff8f8a5780 R15: 0000000000000000
 trace_notifier_run include/trace/events/notifier.h:59 [inline]
 notifier_call_chain+0x219/0x410 kernel/notifier.c:84
 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2229
 call_netdevice_notifiers_extack net/core/dev.c:2267 [inline]
 call_netdevice_notifiers net/core/dev.c:2281 [inline]
 register_netdevice+0x182e/0x2270 net/core/dev.c:11227
 veth_newlink+0x30f/0xa00 drivers/net/veth.c:1855
 rtnl_newlink_create net/core/rtnetlink.c:3825 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3942 [inline]
 rtnl_newlink+0xc45/0x2000 net/core/rtnetlink.c:4057
 rtnetlink_rcv_msg+0x95b/0xe90 net/core/rtnetlink.c:6946
 netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2552
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x5a7/0x870 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1896
 sock_sendmsg_nosec net/socket.c:714 [inline]
 __sock_sendmsg net/socket.c:729 [inline]
 __sys_sendto+0x4a0/0x520 net/socket.c:2228
 __do_sys_sendto net/socket.c:2235 [inline]
 __se_sys_sendto net/socket.c:2231 [inline]
 __x64_sys_sendto+0xe0/0x1c0 net/socket.c:2231
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f55b2590a7c
Code: 2a 5f 02 00 44 8b 4c 24 2c 4c 8b 44 24 20 89 c5 44 8b 54 24 28 48 8b 54 24 18 b8 2c 00 00 00 48 8b 74 24 10 8b 7c 24 08 0f 05 <48> 3d 00 f0 ff ff 77 34 89 ef 48 89 44 24 08 e8 70 5f 02 00 48 8b
RSP: 002b:00007fff71deefa0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f55b32e4620 RCX: 00007f55b2590a7c
RDX: 000000000000006c RSI: 00007f55b32e4670 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007fff71deeff4 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f55b32e4670 R15: 0000000000000000
 </TASK>
task:kworker/u8:11   state:R  running task     stack:22648 pid:9669  tgid:9669  ppid:2      task_flags:0x4208160 flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6961
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7288
 irqentry_exit+0x36/0x90 kernel/entry/common.c:197
 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707
RIP: 0010:write_comp_data+0x0/0x90 kernel/kcov.c:240
Code: 48 8b 05 9b a3 1a 12 48 8b 80 30 16 00 00 e9 57 b8 da 09 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <49> 89 d2 49 89 f8 49 89 f1 65 48 8b 15 67 a3 1a 12 65 8b 05 78 a3
RSP: 0018:ffffc900031b7b20 EFLAGS: 00000246
RAX: 0000000000000001 RBX: ffff888024e954e8 RCX: ffffffff8b605799
RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000001
RBP: 000000000000029d R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000001
R13: 0000000000000000 R14: 0000000000000000 R15: dffffc0000000000
 rcu_read_lock include/linux/rcupdate.h:842 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline]
 batadv_nc_worker+0xc19/0x1030 net/batman-adv/network-coding.c:719
 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3236
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g87057 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=69156
rcu: rcu_preempt kthread starved for 10502 jiffies! g87057 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:27368 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x1190/0x5de0 kernel/sched/core.c:6961
 __schedule_loop kernel/sched/core.c:7043 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7058
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2285
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>