syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	(detected by 1, t=10502 jiffies, g=9073, q=58 ncpus=2)
rcu: All QSes seen, last rcu_preempt kthread activity 10500 (4294956177-4294945677), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10500 jiffies! g9073 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:27752 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 schedule+0xbd/0x170 kernel/sched/core.c:6773
 schedule_timeout+0x160/0x280 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x99/0x380 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: 5798 Comm: syz-executor406 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:lock_release+0x71/0x8b0 kernel/locking/lockdep.c:5762
Code: 41 48 c7 44 24 68 7f c8 5e 8c 48 c7 44 24 70 d0 7a 67 81 4c 8d 7c 24 60 49 c1 ef 03 48 b8 f1 f1 f1 f1 00 f2 f2 f2 4b 89 04 2f <66> 43 c7 44 2f 09 f3 f3 43 c6 44 2f 0b f3 0f 1f 44 00 00 65 8b 05
RSP: 0018:ffffc90000007c60 EFLAGS: 00000802
RAX: f2f2f200f1f1f1f1 RBX: ffffffff817659e8 RCX: c60fa19e75f2c300
RDX: 0000000000000000 RSI: ffffffff817659e8 RDI: ffffffff8cd49988
RBP: ffffc90000007d70 R08: dffffc0000000000 R09: 1ffffffff21b28a1
R10: dffffc0000000000 R11: fffffbfff21b28a2 R12: ffffffff817659e8
R13: dffffc0000000000 R14: 1ffff92000000fb0 R15: 1ffff92000000f98
FS:  0000555590c373c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2a330cff10 CR3: 000000002b417000 CR4: 00000000003506f0
Call Trace:
 <IRQ>
 seqcount_lockdep_reader_access+0xdd/0x1c0 include/linux/seqlock.h:103
 ktime_get_update_offsets_now+0x48/0x3f0 kernel/time/timekeeping.c:2317
 hrtimer_update_base kernel/time/hrtimer.c:661 [inline]
 hrtimer_interrupt+0x134/0x9c0 kernel/time/hrtimer.c:1858
 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 6a 5f f6 f6 48 89 df e8 82 31 f7 f6 e8 5d d8 1a f7 fb bf 01 00 00 00 <e8> 52 53 ea f6 65 8b 05 43 9a 92 75 85 c0 74 02 5b c3 e8 20 80 8f
RSP: 0018:ffffc9000463fc78 EFLAGS: 00000286
RAX: c60fa19e75f2c300 RBX: ffff88802b7a5c80 RCX: c60fa19e75f2c300
RDX: dffffc0000000000 RSI: ffffffff8aaabce0 RDI: 0000000000000001
RBP: ffff88802b7a6118 R08: ffffffff8e4a212f R09: 1ffffffff1c94425
R10: dffffc0000000000 R11: fffffbfff1c94426 R12: 1ffff110056f4c23
R13: 0000000000000021 R14: dffffc0000000000 R15: 0000000000000000
 spin_unlock_irq include/linux/spinlock.h:401 [inline]
 get_signal+0x11f5/0x1400 kernel/signal.c:2905
 arch_do_signal_or_restart+0x9c/0x7b0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xf6/0x180 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+0x61/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f2a330b8899
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 19 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd79b0b3c8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007f2a330b8899
RDX: 000020000006b000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 00007f2a33078990 R09: 00007f2a33078990
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2a3311633c
R13: 00007f2a33110106 R14: 00007ffd79b0b400 R15: 0000000000000000
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.129 msecs