syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P8242/1:b..l
	(detected by 0, t=10502 jiffies, g=35949, q=229)
task:syz.4.1064      state:R  running task     stack:27480 pid: 8242 ppid:  4165 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5027 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373
 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6777
 irqentry_exit+0x53/0x80 kernel/entry/common.c:432
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:rt_mutex_owner kernel/locking/rtmutex_common.h:159 [inline]
RIP: 0010:rtmutex_spin_on_owner kernel/locking/rtmutex.c:1454 [inline]
RIP: 0010:rt_mutex_slowlock_block+0x4a0/0x5d0 kernel/locking/rtmutex.c:1604
Code: 79 8c e8 93 ec 8c f7 48 83 3d 9b ca 3b 02 00 48 8b 5c 24 10 0f 84 2f 01 00 00 48 89 ef e8 e8 a6 fa f6 66 90 84 c0 75 64 f3 90 <48> b8 00 00 00 00 00 fc ff df 41 80 3c 06 00 48 8b 6c 24 18 0f 84
RSP: 0018:ffffc900032d7800 EFLAGS: 00000246
RAX: ffff8880b9100000 RBX: ffffc900032d7a30 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000008 RDI: 0000000000000001
RBP: 0000000000000001 R08: dffffc0000000000 R09: ffffed100fa743b9
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff110048d0b4b
R13: ffff8880744c5974 R14: 1ffff110048d0b4c R15: ffff88807d3a1dc0
 rt_mutex_wait_proxy_lock+0x79/0xf0 kernel/locking/rtmutex_api.c:358
 futex_lock_pi+0xa10/0xf70 kernel/futex/core.c:3138
 do_futex+0x1499/0x1810
 __do_sys_futex kernel/futex/core.c:4059 [inline]
 __se_sys_futex+0x407/0x490 kernel/futex/core.c:4040
 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: 0033:0x7f76376dd719
RSP: 002b:00007f7635b34038 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007f7637895058 RCX: 00007f76376dd719
RDX: 0000000000000000 RSI: 000080000000000d RDI: 000000002000cffc
RBP: 00007f7637750616 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f7637895058 R15: 00007ffc7bcef6b8
 </TASK>
rcu: rcu_preempt kthread starved for 9951 jiffies! g35949 f0x0 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:27256 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5027 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373
 schedule+0x11b/0x1f0 kernel/sched/core.c:6456
 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:287
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 0
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.15.171-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
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:1688 [inline]
 __hrtimer_run_queues+0x55b/0xcf0 kernel/time/hrtimer.c:1752
 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1814
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x13b/0x4b0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
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_irqs_disabled arch/x86/include/asm/irqflags.h:132 [inline]
RIP: 0010:acpi_safe_halt drivers/acpi/processor_idle.c:109 [inline]
RIP: 0010:acpi_idle_do_entry+0x10f/0x340 drivers/acpi/processor_idle.c:562
Code: a9 42 f7 48 83 e3 08 0f 85 0a 01 00 00 4c 8d 74 24 20 e8 34 24 49 f7 0f 1f 44 00 00 e8 da a5 42 f7 0f 00 2d 63 73 a5 00 fb f4 <4c> 89 f3 48 c1 eb 03 42 80 3c 3b 00 74 08 4c 89 f7 e8 cb 7d 8c f7
RSP: 0018:ffffffff8c607b80 EFLAGS: 000002d3
RAX: ffffffff8a3dcdd6 RBX: 0000000000000000 RCX: ffffffff8c6bd5c0
RDX: 0000000000000000 RSI: ffffffff8a8b2a80 RDI: ffffffff8ad90500
RBP: ffffffff8c607c10 R08: ffffffff8186f230 R09: fffffbfff18d7ab9
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffffffff18c0f70
R13: ffff88801e12c004 R14: ffffffff8c607ba0 R15: dffffc0000000000
 acpi_idle_enter+0x352/0x4f0 drivers/acpi/processor_idle.c:697
 cpuidle_enter_state+0x521/0xef0 drivers/cpuidle/cpuidle.c:237
 cpuidle_enter+0x59/0x90 drivers/cpuidle/cpuidle.c:351
 call_cpuidle kernel/sched/idle.c:158 [inline]
 cpuidle_idle_call kernel/sched/idle.c:239 [inline]
 do_idle+0x3e4/0x670 kernel/sched/idle.c:306
 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:403
 start_kernel+0x48c/0x540 init/main.c:1140
 secondary_startup_64_no_verify+0xb1/0xbb
 </TASK>