syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5388/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=9641, q=987 ncpus=2)
task:syz.2.22        state:R  running task     stack:27168 pid:5388  tgid:5388  ppid:5223   flags:0x00000002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5188 [inline]
 __schedule+0xe37/0x5490 kernel/sched/core.c:6529
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:6851
 irqentry_exit+0x36/0x90 kernel/entry/common.c:354
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:pid_nr_ns kernel/pid.c:490 [inline]
RIP: 0010:__task_pid_nr_ns+0x108/0x500 kernel/pid.c:513
Code: 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 0f b6 04 02 84 c0 74 08 3c 03 0f 8e 99 03 00 00 49 8d 7c 24 04 8b ab 80 00 00 00 <48> b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 0f b6 14 02 48
RSP: 0018:ffffc9000334fef8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff888068730220 RCX: ffffffff81568a62
RDX: 1ffff1100d0e6054 RSI: ffffffff81568845 RDI: ffff88802397a784
RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff88802397a780
R13: ffff8880257b1b00 R14: 0000000000000000 R15: 0000000000000000
 task_tgid_vnr include/linux/pid.h:294 [inline]
 __do_sys_getpid+0x1d/0x30 kernel/sys.c:969
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5af696e9a7
RSP: 002b:00007fff4052adc8 EFLAGS: 00000202 ORIG_RAX: 0000000000000027
RAX: ffffffffffffffda RBX: 00007fff4052af30 RCX: 00007f5af696e9a7
RDX: 00007fff4052ae00 RSI: 00007fff4052af30 RDI: 0000000000000021
RBP: 0000000000000000 R08: 00007f5af6af0000 R09: 00007f5af6af2000
R10: 0000000081508c0d R11: 0000000000000202 R12: ffffffff815088cc
R13: 00007f5af6b06018 R14: 0000000000000008 R15: 000000000003b576
 </TASK>
rcu: rcu_preempt kthread starved for 10522 jiffies! g9641 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:27680 pid:17    tgid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5188 [inline]
 __schedule+0xe37/0x5490 kernel/sched/core.c:6529
 __schedule_loop kernel/sched/core.c:6606 [inline]
 schedule+0xe7/0x350 kernel/sched/core.c:6621
 schedule_timeout+0x136/0x2a0 kernel/time/timer.c:2581
 rcu_gp_fqs_loop+0x1eb/0xb00 kernel/rcu/tree.c:2034
 rcu_gp_kthread+0x271/0x380 kernel/rcu/tree.c:2236
 kthread+0x2c1/0x3a0 kernel/kthread.c:389
 ret_from_fork+0x45/0x80 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:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline]
NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:106 [inline]
NMI backtrace for cpu 1 skipped: idling at acpi_safe_halt+0x1a/0x20 drivers/acpi/processor_idle.c:111