rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 0-...!: (10498 ticks this GP) idle=79ac/1/0x4000000000000000 softirq=10630/10630 fqs=5
(t=10500 jiffies g=10333 q=255 ncpus=2)
rcu: rcu_preempt kthread starved for 10489 jiffies! g10333 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:27840 pid:16 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
schedule_timeout+0x15c/0x280 kernel/time/timer.c:2168
rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706
rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4523 Comm: syz.4.21 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:asm_sysvec_apic_timer_interrupt+0x0/0x20 arch/x86/include/asm/idtentry.h:690
Code: e9 f5 04 00 00 90 90 90 90 90 0f 01 ca fc 6a ff e8 f5 03 00 00 48 89 c4 48 89 e7 e8 3a 5a f0 ff e9 d5 04 00 00 90 90 90 90 90 <0f> 01 ca fc 6a ff e8 d5 03 00 00 48 89 c4 48 89 e7 e8 8a 58 f0 ff
RSP: 0018:ffffc900037b7b68 EFLAGS: 00000082
RAX: 9bc905e32475a600 RBX: ffff88802431c0c0 RCX: 9bc905e32475a600
RDX: dffffc0000000000 RSI: ffffffff8a6c0600 RDI: 0000000000000001
RBP: ffff88802431c358 R08: dffffc0000000000 R09: ffffed1004863819
R10: ffffed1004863819 R11: 1ffff11004863818 R12: 1ffff1100486386b
R13: 0000000000000011 R14: dffffc0000000000 R15: 0000000000000000
FS: 000055555b488500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2f663fff CR3: 000000005b8e0000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
Code: f5 ff 0f 1f 00 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 ae 05 49 f7 48 89 df e8 06 cb 49 f7 e8 d1 bd 6c f7 fb bf 01 00 00 00 96 43 3d f7 65 8b 05 27 f1 e7 75 85 c0 74 02 5b c3 e8 c4 02 e6
RSP: 0018:ffffc900037b7b98 EFLAGS: 00000282
spin_unlock_irq include/linux/spinlock.h:401 [inline]
get_signal+0x1163/0x1350 kernel/signal.c:2874
arch_do_signal_or_restart+0xb7/0x1240 arch/x86/kernel/signal.c:871
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fd4a258f749
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:00007fffbeacc288 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007fd4a27e5fa0 RCX: 00007fd4a258f749
RDX: 0000200000000240 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fd4a2613f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd4a27e5fa0 R14: 00007fd4a27e5fa0 R15: 0000000000000004
CPU: 0 PID: 4522 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
Code: f5 ff 0f 1f 00 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 ae 05 49 f7 48 89 df e8 06 cb 49 f7 e8 d1 bd 6c f7 fb bf 01 00 00 00 96 43 3d f7 65 8b 05 27 f1 e7 75 85 c0 74 02 5b c3 e8 c4 02 e6
RSP: 0018:ffffc90003787b98 EFLAGS: 00000282
RAX: db1a934a641a0800 RBX: ffff88802431a500 RCX: db1a934a641a0800
RDX: dffffc0000000000 RSI: ffffffff8a6c0600 RDI: 0000000000000001
RBP: ffff88802431a798 R08: dffffc0000000000 R09: ffffed10048634a1
R10: ffffed10048634a1 R11: 1ffff110048634a0 R12: 1ffff110048634f3
R13: 0000000000000011 R14: dffffc0000000000 R15: 0000000000000000
FS: 0000555594f7f500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2ef63fff CR3: 000000007e617000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
spin_unlock_irq include/linux/spinlock.h:401 [inline]
get_signal+0x1163/0x1350 kernel/signal.c:2874
arch_do_signal_or_restart+0xb7/0x1240 arch/x86/kernel/signal.c:871
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f7893f8f749
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:00007ffe75146fa8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f78941e5fa0 RCX: 00007f7893f8f749
RDX: 0000200000000240 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f7894013f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f78941e5fa0 R14: 00007f78941e5fa0 R15: 0000000000000004