rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (10500 ticks this GP) idle=d7d/1/0x4000000000000000 softirq=6719/6721 fqs=1 
	(t=10502 jiffies g=7601 q=107)
rcu: rcu_preempt kthread starved for 10501 jiffies! g7601 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:27656 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 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: 4418 Comm: syz.4.27 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:debug_smp_processor_id+0x0/0x10 lib/smp_processor_id.c:60
Code: 12 8a e8 43 01 00 00 65 c7 05 e8 55 5a 76 00 00 00 00 48 c7 c7 00 ce 12 8a e8 2c 01 00 00 65 ff 0d d1 55 5a 76 5b c3 00 00 cc <48> c7 c7 e0 a1 59 8a 48 c7 c6 20 a2 59 8a eb 00 55 41 57 41 56 53
RSP: 0018:ffffc9000316fec0 EFLAGS: 00000086
RAX: ffffffff812ba1d4 RBX: ffff88801df7d4c0 RCX: ffff88801df7bb80
RDX: 0000000000000002 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000316ff48 R08: dffffc0000000000 R09: ffffed1003bef771
R10: ffffed1003bef771 R11: 1ffff11003bef770 R12: 0000000000000000
R13: 0000000000000000 R14: dffffc0000000000 R15: 0000000000000000
FS:  00007f3f1ad086c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000006b000 CR3: 000000007a4c7000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 fpregs_assert_state_consistent+0x69/0xe0 arch/x86/kernel/fpu/core.c:420
 arch_exit_to_user_mode_prepare arch/x86/include/asm/entry-common.h:56 [inline]
 exit_to_user_mode_prepare+0x58/0x140 kernel/entry/common.c:216
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f3f1cac92e0
Code: 83 c0 16 83 e0 f7 74 12 50 48 8d 3d 8a 3e 08 00 e8 25 90 f8 ff 0f 1f 44 00 00 c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 <83> ff 21 74 0b c3 66 2e 0f 1f 84 00 00 00 00 00 55 53 48 89 f3 48
RSP: 002b:00007f3f1ad07b38 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f3f1cce7fa8 RCX: 00007f3f1caa0ba9
RDX: 00007f3f1ad07b40 RSI: 00007f3f1ad07c70 RDI: 0000000000000021
RBP: 00007f3f1cce7fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3f1cce8038 R14: 00007ffd762bbe20 R15: 00007ffd762bbf08
 </TASK>
NMI backtrace for cpu 1
CPU: 1 PID: 4415 Comm: syz.2.26 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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:3936 [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:xrstor_from_user_sigframe arch/x86/include/asm/fpu/internal.h:368 [inline]
RIP: 0010:__restore_fpregs_from_user arch/x86/kernel/fpu/signal.c:231 [inline]
RIP: 0010:restore_fpregs_from_user arch/x86/kernel/fpu/signal.c:259 [inline]
RIP: 0010:__fpu_restore_sig arch/x86/kernel/fpu/signal.c:334 [inline]
RIP: 0010:fpu__restore_sig+0x4c0/0xf50 arch/x86/kernel/fpu/signal.c:466
Code: 56 43 90 0a 44 23 6c 24 50 80 7c 24 24 00 0f 85 ad 00 00 00 e8 c1 fa 4b 00 0f 01 cb 4c 89 e7 48 8b 44 24 40 31 d2 48 0f ae 2f <31> c0 41 89 c4 0f 01 ca 31 ff 44 89 e6 e8 fe fd 4b 00 31 ff 4c 89
RSP: 0018:ffffc9000301fb40 EFLAGS: 00040246
RAX: 0000000000000007 RBX: 1ffff1100426ce19 RCX: ffff888021365940
RDX: 0000000000000000 RSI: 0000000000000200 RDI: 00007ffeda442e80
RBP: ffffc9000301fcf0 R08: 0000000000000000 R09: fffff52000603f90
R10: fffff52000603f90 R11: 1ffff92000603f8a R12: 00007ffeda442e80
R13: 0000000000000000 R14: ffff888021365940 R15: dffffc0000000000
 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: 0033:0x7fa259bfcba9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffeda443248 EFLAGS: 00000246
RAX: fffffffffffffffc RBX: 0000000000014f07 RCX: 00007fa259bfcba9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fa259e43fac
RBP: 0000000000000fd2 R08: 002eec9c188d3b7c R09: 0000000dda44353f
R10: 00007ffeda443340 R11: 0000000000000246 R12: 00007fa259e43fac
R13: 00007ffeda443340 R14: 0000000000015ed9 R15: 00007ffeda443360
 </TASK>