rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (1 GPs behind) idle=ed3/1/0x4000000000000000 softirq=17686/17689 fqs=4 
	(t=10502 jiffies g=21633 q=91)
rcu: rcu_preempt kthread starved for 10494 jiffies! g21633 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:28032 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1e0 kernel/sched/core.c:6459
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914
 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145
 kthread+0x436/0x520 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:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 7080 Comm: syz.6.634 Not tainted 5.15.181-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
RIP: 0010:trace_lock_release include/trace/events/lock.h:58 [inline]
RIP: 0010:lock_release+0xb3/0x870 kernel/locking/lockdep.c:5634
Code: 83 fb 08 0f 83 2e 05 00 00 89 d8 c1 e8 06 48 8d 3c c5 e8 aa 68 8d be 08 00 00 00 e8 37 cf 60 00 89 d8 48 0f a3 05 25 47 0c 0c <73> 0d e8 d6 34 07 00 84 c0 0f 84 34 05 00 00 48 c7 c0 84 de 68 8d
RSP: 0018:ffffc90002e9fba0 EFLAGS: 00000257
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff815c63b9
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8d68aae8
RBP: ffffc90002e9fcb8 R08: dffffc0000000000 R09: fffffbfff1ad155e
R10: fffffbfff1ad155e R11: 1ffffffff1ad155d R12: ffff888062ecc118
R13: dffffc0000000000 R14: ffffc90002e9fd60 R15: 1ffff920005d3f80
FS:  00007fed453db6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000006b000 CR3: 000000005519d000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 _copy_from_user+0x29/0x170 lib/usercopy.c:14
 copy_from_user include/linux/uaccess.h:192 [inline]
 restore_sigcontext arch/x86/kernel/signal.c:91 [inline]
 __ia32_sys_rt_sigreturn+0x1e6/0x790 arch/x86/kernel/signal.c:674
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fed4750fb39
Code: 64 c7 00 16 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 0f 05 <0f> 1f 80 00 00 00 00 48 81 ec 48 01 00 00 49 89 d0 64 48 8b 04 25
RSP: 002b:00007fed453dab40 EFLAGS: 00000206 ORIG_RAX: 000000000000000f
RAX: ffffffffffffffda RBX: 00007fed4779afa8 RCX: 00007fed4750fb39
RDX: 00007fed453dab40 RSI: 00007fed453dac70 RDI: 0000000000000021
RBP: 00007fed4779afa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 00007fed4779afac
R13: 0000000000000000 R14: 00007ffedc683f10 R15: 00007ffedc683ff8
 </TASK>
NMI backtrace for cpu 1
CPU: 1 PID: 7076 Comm: syz.5.633 Not tainted 5.15.181-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
Call Trace:
 <IRQ>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_dump_cpu_stacks+0x22f/0x380 kernel/rcu/tree_stall.h:349
 print_cpu_stall+0x31d/0x5f0 kernel/rcu/tree_stall.h:633
 check_cpu_stall kernel/rcu/tree_stall.h:727 [inline]
 rcu_pending kernel/rcu/tree.c:3932 [inline]
 rcu_sched_clock_irq+0x6d8/0x1110 kernel/rcu/tree.c:2619
 update_process_times+0x193/0x200 kernel/time/timer.c:1818
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1690 [inline]
 __hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1754
 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 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:preempt_count arch/x86/include/asm/preempt.h:27 [inline]
RIP: 0010:__local_bh_disable_ip+0xd9/0x190 kernel/softirq.c:326
Code: 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 0f 85 9d 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 65 8b 05 7f 14 ba 7e <25> ff ff ff 7f 39 d8 75 41 48 8b 5d 08 48 89 df e8 52 b4 14 00 85
RSP: 0018:ffffc90002e6fa80 EFLAGS: 00000206
RAX: 0000000080000200 RBX: 0000000000000200 RCX: ffffffff9609ff03
RDX: 0000000000000000 RSI: 0000000000000200 RDI: ffffffff812bda15
RBP: ffffc90002e6fb30 R08: 0000000000000000 R09: fffff520005cdf90
R10: fffff520005cdf90 R11: 1ffff920005cdf8a R12: 1ffff920005cdf50
R13: 00000000000002f8 R14: 0000000000000246 R15: dffffc0000000000
 fpregs_lock arch/x86/include/asm/fpu/api.h:70 [inline]
 restore_fpregs_from_user arch/x86/kernel/fpu/signal.c:257 [inline]
 __fpu_restore_sig arch/x86/kernel/fpu/signal.c:334 [inline]
 fpu__restore_sig+0x45d/0xf50 arch/x86/kernel/fpu/signal.c:466
 restore_sigcontext arch/x86/kernel/signal.c:139 [inline]
 __ia32_sys_rt_sigreturn+0x649/0x790 arch/x86/kernel/signal.c:674
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f94b54d8225
Code: 24 0c 89 3c 24 48 89 4c 24 18 e8 f6 54 ff ff 4c 8b 54 24 18 48 8b 54 24 10 41 89 c0 8b 74 24 0c 8b 3c 24 b8 e6 00 00 00 0f 05 <44> 89 c7 48 89 04 24 e8 4f 55 ff ff 48 8b 04 24 48 83 c4 28 f7 d8
RSP: 002b:00007ffc077fa950 EFLAGS: 00000293
RAX: fffffffffffffffc RBX: 00007f94b56ccfa0 RCX: 00007f94b54d8225
RDX: 00007ffc077fa990 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f94b56ceba0 R08: 0000000000000000 R09: 0008c01a60cc5d56
R10: 0000000000000000 R11: 0000000000000293 R12: 000000000004b16c
R13: 00007ffc077faab0 R14: ffffffffffffffff R15: 00007ffc077faad0
 </TASK>