syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 1, t=10502 jiffies, g=3561, q=22)
rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4294966900-4294956398), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10502 jiffies! g3561 f0x2 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:27000 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1f0 kernel/sched/core.c:6459
 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1914
 rcu_gp_fqs_loop+0x2bf/0x1080 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:300
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 1
CPU: 1 PID: 3553 Comm: syz-executor239 Not tainted 5.15.158-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_check_gp_kthread_starvation+0x1d2/0x240 kernel/rcu/tree_stall.h:487
 print_other_cpu_stall+0x137a/0x14d0 kernel/rcu/tree_stall.h:592
 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
 rcu_pending kernel/rcu/tree.c:3932 [inline]
 rcu_sched_clock_irq+0xa38/0x1150 kernel/rcu/tree.c:2619
 update_process_times+0x196/0x200 kernel/time/timer.c:1818
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x386/0x550 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1686 [inline]
 __hrtimer_run_queues+0x55b/0xcf0 kernel/time/hrtimer.c:1750
 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1812
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1085 [inline]
 __sysvec_apic_timer_interrupt+0x139/0x470 arch/x86/kernel/apic/apic.c:1102
 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1096
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:22 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:106 [inline]
RIP: 0010:lock_acquire+0x14d/0x4f0 kernel/locking/lockdep.c:5619
Code: c3 ec 0a 00 00 48 89 d8 48 c1 e8 03 42 0f b6 04 28 84 c0 0f 85 c4 02 00 00 83 3b 00 0f 85 5c 01 00 00 4c 8d bc 24 80 00 00 00 <4c> 89 fb 48 c1 eb 03 42 80 3c 2b 00 74 08 4c 89 ff e8 5d 88 67 00
RSP: 0018:ffffc90002e77d80 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff8880232e642c RCX: ffffffff8162ac6c
RDX: 0000000000000000 RSI: ffffffff8ad8f5e0 RDI: ffffffff8ad8f5a0
RBP: ffffc90002e77ed8 R08: dffffc0000000000 R09: fffffbfff1bc8c56
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff920005cefb8
R13: dffffc0000000000 R14: 0000000000000000 R15: ffffc90002e77e00
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:312
 rcu_read_lock include/linux/rcupdate.h:739 [inline]
 __task_pid_nr_ns+0x20/0x420 kernel/pid.c:497
 task_tgid_vnr include/linux/sched.h:1587 [inline]
 __do_sys_getpid+0x19/0x20 kernel/sys.c:945
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f2acdcd4387
Code: 0b e9 68 fe ff ff 48 83 c4 18 48 8d 3d 52 0f 09 00 5b 5d 41 5c 41 5d 41 5e 41 5f e9 53 d8 fd ff 0f 1f 00 b8 27 00 00 00 0f 05 <c3> 0f 1f 84 00 00 00 00 00 31 f6 31 ff e9 c7 e5 02 00 0f 1f 80 00
RSP: 002b:00007ffd150fb4c8 EFLAGS: 00000202 ORIG_RAX: 0000000000000027
RAX: ffffffffffffffda RBX: 00007ffd150fb630 RCX: 00007f2acdcd4387
RDX: 00007ffd150fb500 RSI: 00007ffd150fb630 RDI: 0000000000000021
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000555555999370
R13: 0000000000000002 R14: 00007ffd150fbb00 R15: 00007ffd150fbaf0
 </TASK>