syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	(detected by 1, t=10502 jiffies, g=9329, q=185 ncpus=2)
rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4294958171-4294947668), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10504 jiffies! g9329 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R  running task     stack:27656 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5381 [inline]
 __schedule+0x1553/0x45a0 kernel/sched/core.c:6700
 schedule+0xbd/0x170 kernel/sched/core.c:6774
 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x313/0x1590 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5803 Comm: syz-executor137 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:__lock_release kernel/locking/lockdep.c:5438 [inline]
RIP: 0010:lock_release+0x22c/0x8c0 kernel/locking/lockdep.c:5774
Code: 44 89 7c 24 3c 44 89 fa 85 c0 0f 84 d7 01 00 00 4d 85 e4 0f 84 01 03 00 00 4d 8d 74 24 24 4c 89 f0 48 c1 e8 03 42 0f b6 04 28 <84> c0 0f 85 9d 04 00 00 41 83 3e 00 0f 85 ca 03 00 00 4d 8d 74 24
RSP: 0018:ffffc90000007c40 EFLAGS: 00000803
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff8d14bac8 RDI: ffff88807be1a8e0
RBP: ffffc90000007d50 R08: ffffffff8e8aeeef R09: 1ffffffff1d15ddd
R10: dffffc0000000000 R11: fffffbfff1d15dde R12: ffff88807be1a8e0
R13: dffffc0000000000 R14: ffff88807be1a904 R15: 0000000000000000
FS:  0000555575c1f3c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000006b000 CR3: 0000000077f9e000 CR4: 00000000003506f0
Call Trace:
 <IRQ>
 seqcount_lockdep_reader_access+0xe4/0x1d0 include/linux/seqlock.h:103
 ktime_get+0x35/0x280 kernel/time/timekeeping.c:846
 clockevents_program_event+0xe6/0x310 kernel/time/clockevents.c:326
 hrtimer_interrupt+0x5a1/0x9c0 kernel/time/hrtimer.c:1889
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline]
 __sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0x9f/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:__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: 00 f3 0f 1e fa 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 aa ec d9 f6 48 89 df e8 62 c1 da f6 e8 1d ce fe f6 fb bf 01 00 00 00 <e8> 82 c8 cd f6 65 8b 05 a3 f7 74 75 85 c0 74 02 5b c3 e8 20 df 71
RSP: 0018:ffffc900047efc78 EFLAGS: 00000286
RAX: 77de6e5d7c9edd00 RBX: ffff88802e09c0c0 RCX: 77de6e5d7c9edd00
RDX: dffffc0000000000 RSI: ffffffff8acac960 RDI: 0000000000000001
RBP: ffff88802e09c558 R08: ffffffff8e8aeeef R09: 1ffffffff1d15ddd
R10: dffffc0000000000 R11: fffffbfff1d15dde R12: 1ffff11005c138ab
R13: 0000000000000021 R14: dffffc0000000000 R15: 0000000000000000
 spin_unlock_irq include/linux/spinlock.h:401 [inline]
 get_signal+0x11f5/0x13f0 kernel/signal.c:2905
 arch_do_signal_or_restart+0xc2/0x800 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f5ca9743589
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 0f 1f 44 00 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 d0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd5f406378 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007f5ca9743589
RDX: 000020000006b000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 00007ffd5f4063b0 R09: 00007ffd5f4063b0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd5f40639c
R13: 00007f5ca97ec488 R14: 0000000000000000 R15: 431bde82d7b634db
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.018 msecs