syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P9106/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=59997, q=805 ncpus=2)
task:udevd           state:R  running task     stack:24344 pid:9106  tgid:9106  ppid:4671   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5188 [inline]
 __schedule+0x1800/0x4a60 kernel/sched/core.c:6529
 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:6851
 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:5763
Code: 2b 00 74 08 4c 89 f7 e8 2a f3 8a 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:ffffc900036dfbe0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff920006dbf88 RCX: 61417720dfeb2e00
RDX: dffffc0000000000 RSI: ffffffff8c0ae6e0 RDI: ffffffff8c605d00
RBP: ffffc900036dfd28 R08: ffffffff9372c807 R09: 1ffffffff26e5900
R10: dffffc0000000000 R11: fffffbfff26e5901 R12: 1ffff920006dbf84
R13: dffffc0000000000 R14: ffffc900036dfc40 R15: 0000000000000246
 rcu_lock_acquire include/linux/rcupdate.h:326 [inline]
 rcu_read_lock include/linux/rcupdate.h:838 [inline]
 devcgroup_legacy_check_permission security/device_cgroup.c:838 [inline]
 devcgroup_check_permission+0x59/0x950 security/device_cgroup.c:868
 devcgroup_inode_permission include/linux/device_cgroup.h:36 [inline]
 inode_permission+0x358/0x460 fs/namei.c:539
 path_permission include/linux/fs.h:2849 [inline]
 inotify_find_inode fs/notify/inotify/inotify_user.c:381 [inline]
 __do_sys_inotify_add_watch fs/notify/inotify/inotify_user.c:776 [inline]
 __se_sys_inotify_add_watch+0x26a/0x1070 fs/notify/inotify/inotify_user.c:729
 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: 0033:0x7fdd26923ee7
RSP: 002b:00007ffc4babc548 EFLAGS: 00000202 ORIG_RAX: 00000000000000fe
RAX: ffffffffffffffda RBX: 000055c53a9e4e10 RCX: 00007fdd26923ee7
RDX: 0000000000000008 RSI: 000055c53a9e5dd0 RDI: 0000000000000007
RBP: 000055c53a9e4e10 R08: 0000000000000001 R09: 784d6a16098dc0f8
R10: 00000000000001b6 R11: 0000000000000202 R12: 000055c53a9ef080
R13: 000055c53a9d56f0 R14: 0000000000000008 R15: 000055c53a9c3910
 </TASK>
rcu: rcu_preempt kthread starved for 10523 jiffies! g59997 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R  running task     stack:26000 pid:17    tgid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5188 [inline]
 __schedule+0x1800/0x4a60 kernel/sched/core.c:6529
 __schedule_loop kernel/sched/core.c:6606 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6621
 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2581
 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2034
 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2236
 kthread+0x2f2/0x390 kernel/kthread.c:389
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.11.0-rc2-syzkaller-00011-geb5e56d14912 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline]
RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:92 [inline]
RIP: 0010:acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:112
Code: 90 90 90 90 90 90 90 90 90 65 48 8b 04 25 40 d7 03 00 48 f7 00 08 00 00 00 75 10 eb 07 0f 00 2d e5 0f b4 00 f3 0f 1e fa fb f4 <fa> e9 24 40 3a 00 66 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90
RSP: 0018:ffffc900001a7d08 EFLAGS: 00000246
RAX: ffff888017ef0000 RBX: ffff8880192ad064 RCX: 0000000000961b09
RDX: 0000000000000001 RSI: ffff8880192ad000 RDI: ffff8880192ad064
RBP: 000000000003a6b8 R08: ffff8880b9337c7b R09: 1ffff11017266f8f
R10: dffffc0000000000 R11: ffffffff8bb5fc90 R12: ffff88801d721000
R13: 0000000000000000 R14: 0000000000000001 R15: ffffffff8f0dc680
FS:  0000000000000000(0000) GS:ffff8880b9300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fae02a93fa8 CR3: 000000002c282000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 </IRQ>
 <TASK>
 acpi_idle_enter+0xe4/0x140 drivers/acpi/processor_idle.c:702
 cpuidle_enter_state+0x114/0x480 drivers/cpuidle/cpuidle.c:267
 cpuidle_enter+0x5d/0xa0 drivers/cpuidle/cpuidle.c:388
 call_cpuidle kernel/sched/idle.c:155 [inline]
 cpuidle_idle_call kernel/sched/idle.c:230 [inline]
 do_idle+0x375/0x5d0 kernel/sched/idle.c:326
 cpu_startup_entry+0x42/0x60 kernel/sched/idle.c:424
 start_secondary+0x100/0x100 arch/x86/kernel/smpboot.c:313
 common_startup_64+0x13e/0x147
 </TASK>
vkms_vblank_simulate: vblank timer overrun