syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 ticks this GP) idle=2b0c/1/0x4000000000000000 softirq=29034/29034 fqs=0
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P6072/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=26605, q=174 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 8104 Comm: udevd Not tainted 6.14.0-rc6-syzkaller-00103-g4003c9e78778 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:__raw_callee_save___pv_queued_spin_unlock+0x10/0x18
Code: 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 52 b8 01 00 00 00 31 d2 f0 0f b0 17 <75> 06 5a e9 63 ab 04 f5 56 0f b6 f0 e8 9f ff ff ff 5e 5a e9 53 ab
RSP: 0018:ffffc90000a28ad0 EFLAGS: 00000046
RAX: 0000000000000001 RBX: 1ffffffff351fc70 RCX: 0000000000000001
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffff9a8fe378
RBP: dffffc0000000000 R08: ffffffff9a8fe37b R09: 1ffffffff351fc6f
R10: dffffc0000000000 R11: fffffbfff351fc70 R12: 1ffffffff351fc71
R13: ffffffff9a8fe388 R14: ffffffff9a8fe380 R15: ffffffff9a8fe378
FS:  00007fb1deebec80(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000557daf125950 CR3: 000000006b2a8000 CR4: 0000000000350ef0
Call Trace:
 <NMI>
 </NMI>
 <IRQ>
 pv_queued_spin_unlock arch/x86/include/asm/paravirt.h:582 [inline]
 queued_spin_unlock arch/x86/include/asm/qspinlock.h:57 [inline]
 do_raw_spin_unlock+0x13c/0x8b0 kernel/locking/spinlock_debug.c:142
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:150 [inline]
 _raw_spin_unlock_irqrestore+0x81/0x140 kernel/locking/spinlock.c:194
 debug_object_activate+0x3f7/0x580 lib/debugobjects.c:836
 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:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xd8/0x140 kernel/locking/spinlock.c:194
Code: 9c 8f 44 24 20 42 80 3c 23 00 74 08 4c 89 f7 e8 2e 9f 1d f6 f6 44 24 21 02 75 52 41 f7 c7 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> 73 fd 83 f5 65 8b 05 c4 50 f8 73 85 c0 74 43 48 c7 04 24 0e 36
RSP: 0018:ffffc90002fe7ce0 EFLAGS: 00000206
RAX: 89ba91d1083ae300 RBX: 1ffff920005fcfa0 RCX: ffffffff9a653903
RDX: dffffc0000000000 RSI: ffffffff8c2ab3a0 RDI: 0000000000000001
RBP: ffffc90002fe7d80 R08: ffffffff903cfa77 R09: 1ffffffff2079f4e
R10: dffffc0000000000 R11: fffffbfff2079f4f R12: dffffc0000000000
R13: 1ffff920005fcf9c R14: ffffc90002fe7d00 R15: 0000000000000246
 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
 __wake_up_common_lock+0x18c/0x1e0 kernel/sched/wait.c:108
 fsnotify_insert_event+0x35f/0x430 fs/notify/notification.c:127
 fsnotify_add_event include/linux/fsnotify_backend.h:697 [inline]
 inotify_handle_inode_event+0x3f6/0x5f0 fs/notify/inotify/inotify_fsnotify.c:126
 inotify_ignored_and_remove_idr+0x29/0x70 fs/notify/inotify/inotify_user.c:526
 __do_sys_inotify_rm_watch fs/notify/inotify/inotify_user.c:805 [inline]
 __se_sys_inotify_rm_watch+0xc2/0x130 fs/notify/inotify/inotify_user.c:786
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb1deb23f77
Code: 73 01 c3 48 8b 0d b1 ce 0c 00 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 ff 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 81 ce 0c 00 f7 d8 64 89 01 48
RSP: 002b:00007ffcadb53eb8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ff
RAX: ffffffffffffffda RBX: 000055e32dc6d120 RCX: 00007fb1deb23f77
RDX: 0000000000000007 RSI: 0000000000000411 RDI: 0000000000000007
RBP: 000055e359ae8d30 R08: 0000000000000006 R09: abccc978e864143d
R10: 0000000000000010 R11: 0000000000000246 R12: 0000000000000411
R13: 00007ffcadb53ec8 R14: 0000000003938700 R15: 000055e32dc6d160
 </TASK>
task:kworker/u8:11   state:R  running task     stack:22352 pid:6072  tgid:6072  ppid:2      task_flags:0x4208060 flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5378 [inline]
 __schedule+0x190e/0x4c90 kernel/sched/core.c:6765
 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:7087
 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354
 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 8a 50 8c 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:ffffc900044cf940 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff92000899f34 RCX: ffff88803030a8e8
RDX: dffffc0000000000 RSI: ffffffff8c2ac600 RDI: ffffffff8c810120
RBP: ffffc900044cfaa0 R08: ffffffff9454c847 R09: 1ffffffff28a9908
R10: dffffc0000000000 R11: fffffbfff28a9909 R12: 1ffff92000899f30
R13: dffffc0000000000 R14: ffffc900044cf9a0 R15: 0000000000000246
 rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 rcu_read_lock include/linux/rcupdate.h:849 [inline]
 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline]
 batadv_nc_worker+0xec/0x610 net/batman-adv/network-coding.c:719
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xac0/0x18e0 kernel/workqueue.c:3319
 worker_thread+0x870/0xd30 kernel/workqueue.c:3400
 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>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g26605 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=28205
rcu: rcu_preempt kthread starved for 10502 jiffies! g26605 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1
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:25944 pid:18    tgid:18    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5378 [inline]
 __schedule+0x190e/0x4c90 kernel/sched/core.c:6765
 __schedule_loop kernel/sched/core.c:6842 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6857
 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>