rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 0-...!: (1 GPs behind) idle=e50c/1/0x4000000000000000 softirq=35316/35317 fqs=2
(t=10501 jiffies g=42245 q=20 ncpus=2)
rcu: rcu_preempt kthread starved for 10498 jiffies! g42245 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:28016 pid:16 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
schedule+0xb9/0x180 kernel/sched/core.c:6638
schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2168
rcu_gp_fqs_loop+0x303/0x1340 kernel/rcu/tree.c:1706
rcu_gp_kthread+0x99/0x3b0 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: 10247 Comm: syz.1.1982 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:timerqueue_del+0x1/0x100 lib/timerqueue.c:54
Code: e8 48 83 c4 18 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 14 0a 65 f7 0f 0b e9 78 fe ff ff 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 55 <41> 57 41 56 41 55 41 54 53 49 89 f6 48 89 fb 49 bd 00 00 00 00 00
RSP: 0018:ffffc900001e0d10 EFLAGS: 00000002
RAX: ffffffff817267c0 RBX: ffff8880b8f2a688 RCX: 0000000000010000
RDX: ffff88802be41dc0 RSI: ffff88807b619250 RDI: ffff8880b8f2a690
RBP: ffffc900001e0e88 R08: ffffffff8e1fcd2f R09: 1ffffffff1c3f9a5
R10: dffffc0000000000 R11: fffffbfff1c3f9a6 R12: ffff88807b619250
R13: dffffc0000000000 R14: ffff8880b8f2a5c0 R15: 0000000000000001
FS: 00007faa133c56c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c2ba2c3 CR3: 000000007c009000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
__remove_hrtimer kernel/time/hrtimer.c:1138 [inline]
__run_hrtimer kernel/time/hrtimer.c:1727 [inline]
__hrtimer_run_queues+0x3a0/0xd70 kernel/time/hrtimer.c:1811
hrtimer_interrupt+0x3c5/0x9c0 kernel/time/hrtimer.c:1873
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline]
__sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1118
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
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: 00 00 00 66 90 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 9e 02 2e f7 48 89 df e8 e6 ca 2e f7 e8 31 1f 52 f7 fb bf 01 00 00 00 86 2b 22 f7 65 8b 05 47 b0 cb 75 85 c0 74 02 5b c3 e8 94 c4 c9
RSP: 0018:ffffc90003ce7b98 EFLAGS: 00000282
RAX: 9032ba7861e8f700 RBX: ffff8880792f1280 RCX: 9032ba7861e8f700
RDX: dffffc0000000000 RSI: ffffffff8a8c1220 RDI: 0000000000000001
RBP: ffff8880792f1718 R08: ffff8880792f1283 R09: 1ffff1100f25e250
R10: dffffc0000000000 R11: ffffed100f25e251 R12: 1ffff1100f25e2e3
R13: 0000000000000021 R14: dffffc0000000000 R15: 0000000000000000
spin_unlock_irq include/linux/spinlock.h:401 [inline]
get_signal+0x1163/0x1350 kernel/signal.c:2874
arch_do_signal_or_restart+0xc4/0x1350 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:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7faa1259c627
Code: 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89
RSP: 002b:00007faa133c5028 EFLAGS: 00000246
RAX: 0000000000000113 RBX: 00007faa12815fa0 RCX: 00007faa1259c629
RDX: 0000000000000006 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 00007faa12632b39 R08: 0000000000000007 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007faa12816038 R14: 00007faa12815fa0 R15: 00007fff094d10b8
CPU: 0 PID: 10248 Comm: syz.4.1981 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x0/0x80 kernel/kcov.c:314
Code: 28 4d 39 ca 77 22 89 ff 89 f6 49 ff c0 4c 89 01 48 c7 44 11 08 03 00 00 00 48 89 7c 11 10 48 89 74 11 18 48 89 44 11 20 c3 90 <48> 8b 04 24 65 48 8b 15 b4 f6 7f 7e 65 8b 0d b5 f6 7f 7e 81 e1 00
RSP: 0018:ffffc90003be7b00 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff888024f58000 RCX: 0000000000080000
RDX: ffffc9000ef71000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 000000000000004b R08: ffffc90003be7c7f R09: ffffc90003be7c50
R10: dffffc0000000000 R11: fffff5200077cf90 R12: dffffc0000000000
R13: 00007fa47c8add00 R14: ffffffff8a86b260 R15: 0000000000000000
FS: 00007fa47c8ae6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000006b000 CR3: 0000000023f33000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
pagefault_disabled include/linux/uaccess.h:228 [inline]
__might_fault+0x4e/0x120 mm/memory.c:5846
__copy_from_user include/linux/uaccess.h:75 [inline]
check_xstate_in_sigframe arch/x86/kernel/fpu/signal.c:35 [inline]
__fpu_restore_sig arch/x86/kernel/fpu/signal.c:348 [inline]
fpu__restore_sig+0x246/0x1290 arch/x86/kernel/fpu/signal.c:493
restore_sigcontext arch/x86/kernel/signal.c:140 [inline]
__ia32_sys_rt_sigreturn+0x5e4/0x760 arch/x86/kernel/signal.c:675
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fa47b99c627
Code: 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89
RSP: 002b:00007fa47c8ae0e8 EFLAGS: 00000246
RAX: 00000000000000ca RBX: 00007fa47bc15fa8 RCX: 00007fa47b99c629
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fa47bc15fa8
RBP: 00007fa47bc15fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa47bc16038 R14: 00007fff3a88a380 R15: 00007fff3a88a468