rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (10499 ticks this GP) idle=b62c/1/0x4000000000000000 softirq=8244/8244 fqs=1
	(t=10500 jiffies g=7781 q=334 ncpus=2)
rcu: rcu_preempt kthread starved for 10498 jiffies! g7781 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:27736 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 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
 </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: 4330 Comm: syz-executor175 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:check_region_inline mm/kasan/generic.c:169 [inline]
RIP: 0010:kasan_check_range+0xe/0x290 mm/kasan/generic.c:189
Code: 0f 0b b8 ea ff ff ff c3 0f 0b b8 ea ff ff ff c3 00 00 cc cc 00 00 cc cc 00 00 cc cc b0 01 48 85 f6 0f 84 ac 01 00 00 55 41 57 <41> 56 41 54 53 49 89 f8 49 01 f0 0f 82 0e 02 00 00 49 89 f8 49 c1
RSP: 0018:ffffc90000007ac8 EFLAGS: 00000002
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff81643f64
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e1fcd28
RBP: ffffc90000007bf0 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff215ea49 R12: 0000000000000000
R13: 1ffff92000000f68 R14: 0000000000000000 R15: dffffc0000000000
FS:  000055555ed583c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000bbdffc CR3: 000000006a04f000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 instrument_atomic_read include/linux/instrumented.h:72 [inline]
 _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
 cpumask_test_cpu include/linux/cpumask.h:444 [inline]
 cpu_online include/linux/cpumask.h:1030 [inline]
 trace_lock_acquire include/trace/events/lock.h:24 [inline]
 lock_acquire+0xd4/0x4a0 kernel/locking/lockdep.c:5633
 rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 rcu_read_lock include/linux/rcupdate.h:791 [inline]
 __lock_task_sighand+0x42/0x2d0 kernel/signal.c:1394
 lock_task_sighand include/linux/sched/signal.h:745 [inline]
 send_sigqueue+0x159/0x610 kernel/signal.c:1979
 posix_timer_event kernel/time/posix-timers.c:360 [inline]
 posix_timer_fn+0x16a/0x3d0 kernel/time/posix-timers.c:386
 __run_hrtimer kernel/time/hrtimer.c:1747 [inline]
 __hrtimer_run_queues+0x560/0xd70 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
 </IRQ>
 <TASK>
 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 <e8> 86 2b 22 f7 65 8b 05 47 b0 cb 75 85 c0 74 02 5b c3 e8 94 c4 c9
RSP: 0018:ffffc90004257b98 EFLAGS: 00000282
RAX: b5907b6d2929a500 RBX: ffff88802e6d40c0 RCX: b5907b6d2929a500
RDX: dffffc0000000000 RSI: ffffffff8a8c1220 RDI: 0000000000000001
RBP: ffff88802e6d4558 R08: ffff88802e6d40c3 R09: 1ffff11005cda818
R10: dffffc0000000000 R11: ffffed1005cda819 R12: 1ffff11005cda8ab
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: 0033:0x7f2c9bd28c1e
Code: 08 0f 85 e5 e1 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 <c3> 90 41 57 41 56 4d 89 c6 41 55 4d 89 cd 41 54 55 53 48 83 ec 08
RSP: 002b:00007ffdb56e05d8 EFLAGS: 00000246
RAX: fffffffffffffff7 RBX: 000055555ed583c0 RCX: 00007f2c9bd28c1e
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2c9bd7751b
R13: 00007f2c9bd774f1 R14: 00007ffdb56e0670 R15: 0000000000000000
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.013 msecs
CPU: 1 PID: 4329 Comm: syz-executor175 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:copy_user_generic arch/x86/include/asm/uaccess_64.h:46 [inline]
RIP: 0010:raw_copy_from_user arch/x86/include/asm/uaccess_64.h:52 [inline]
RIP: 0010:_copy_from_user+0xf4/0x170 lib/usercopy.c:23
Code: fd 49 29 dc 72 61 4d 39 fc 72 5c e8 06 82 71 fd 0f ae e8 4c 89 f7 89 de e8 69 6f c2 fd 4c 89 fe 4c 89 f7 89 da e8 4c 2c 0f 06 <41> 89 c7 31 ff 4c 89 fe e8 bf 85 71 fd 4d 85 ff 75 11 e8 d5 81 71
RSP: 0018:ffffc90004247bd0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000018 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 00007ffdb56e00a8 RDI: ffffc90004247c78
RBP: 0000000000000000 R08: 0000000000000000 R09: 1ffff92000848f8e
R10: dffffc0000000000 R11: fffff52000848f8f R12: 00007fffffffefe8
R13: dffffc0000000000 R14: ffffc90004247c60 R15: 00007ffdb56e0090
FS:  000055555ed583c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000bbdffc CR3: 0000000027343000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 copy_from_user include/linux/uaccess.h:161 [inline]
 restore_altstack+0xa8/0x4c0 kernel/signal.c:4257
 __ia32_sys_rt_sigreturn+0x619/0x760 arch/x86/kernel/signal.c:678
 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: 0033:0x7f2c9bd02009
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffdb56e0638 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007f2c9bd02009
RDX: 0000200000000240 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 00007f2c9bd7723a R09: 00007f2c9bd7723a
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2c9bd7751b
R13: 00007f2c9bd774f1 R14: 00007ffdb56e0670 R15: 0000000000000000
 </TASK>
sched: RT throttling activated