rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5882/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=9657, q=678 ncpus=2)
task:syz-executor state:R running task stack:21736 pid:5882 ppid:5875 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5380 [inline]
__schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6866
preempt_schedule+0xab/0xc0 kernel/sched/core.c:6890
preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
__raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
_raw_spin_unlock+0x3a/0x40 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
copy_pte_range mm/memory.c:1107 [inline]
copy_pmd_range mm/memory.c:1168 [inline]
copy_pud_range mm/memory.c:1205 [inline]
copy_p4d_range mm/memory.c:1229 [inline]
copy_page_range+0x2b7c/0x3600 mm/memory.c:1323
dup_mmap kernel/fork.c:764 [inline]
dup_mm kernel/fork.c:1692 [inline]
copy_mm+0x11a8/0x1ca0 kernel/fork.c:1741
copy_process+0x16d3/0x3d70 kernel/fork.c:2506
kernel_clone+0x21b/0x840 kernel/fork.c:2914
__do_sys_clone kernel/fork.c:3057 [inline]
__se_sys_clone kernel/fork.c:3041 [inline]
__x64_sys_clone+0x18c/0x1e0 kernel/fork.c:3041
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f0415f85e93
RSP: 002b:00007fff4c997e68 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f0415f85e93
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: 00005555855f87d0 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f04161b4280 R14: 0000000000000003 R15: 00007fff4c998000
rcu: rcu_preempt kthread starved for 10528 jiffies! g9657 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:27752 pid:17 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5380 [inline]
__schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
schedule+0xbd/0x170 kernel/sched/core.c:6773
schedule_timeout+0x160/0x280 kernel/time/timer.c:2168
rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667
rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
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: 5989 Comm: syz.1.18 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:mark_usage kernel/locking/lockdep.c:4552 [inline]
RIP: 0010:__lock_acquire+0xc20/0x7c80 kernel/locking/lockdep.c:5091
Code: 4b e3 0c 00 0f 84 15 10 00 00 83 bc 24 b8 00 00 00 00 4c 8b b4 24 90 00 00 00 0f 84 23 01 00 00 48 8b 44 24 48 42 0f b6 04 00 <84> c0 0f 85 c2 5d 00 00 41 8b 07 66 85 c0 0f 88 e5 00 00 00 65 8b
RSP: 0018:ffffc90000007760 EFLAGS: 00000002
RAX: 0000000000000000 RBX: 0000000000000002 RCX: 0000000000000002
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff90d94500
RBP: ffffc900000079a8 R08: dffffc0000000000 R09: 1ffffffff21b28a0
R10: dffffc0000000000 R11: fffffbfff21b28a1 R12: 0000000000000002
R13: ffff88802b311e00 R14: ffff88802b312930 R15: ffff88802b312950
FS: 0000555563691500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b33c63fff CR3: 000000006ba1a000 CR4: 00000000003506f0
Call Trace:
reacquire_held_locks+0x2ff/0x5a0 kernel/locking/lockdep.c:5279
__lock_release kernel/locking/lockdep.c:5468 [inline]
lock_release+0x32b/0x8b0 kernel/locking/lockdep.c:5774
rcu_lock_release include/linux/rcupdate.h:344 [inline]
rcu_read_unlock include/linux/rcupdate.h:819 [inline]
__lock_task_sighand+0x2b4/0x2d0 kernel/signal.c:1429
lock_task_sighand include/linux/sched/signal.h:742 [inline]
send_sigqueue+0x239/0x710 kernel/signal.c:2009
posix_timer_event kernel/time/posix-timers.c:299 [inline]
posix_timer_fn+0x16e/0x3d0 kernel/time/posix-timers.c:325
__run_hrtimer kernel/time/hrtimer.c:1750 [inline]
__hrtimer_run_queues+0x51e/0xc40 kernel/time/hrtimer.c:1814
hrtimer_interrupt+0x3c9/0x9c0 kernel/time/hrtimer.c:1876
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline]
__sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1088
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:202
Code: 00 f3 0f 1e fa 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 6a 5f f6 f6 48 89 df e8 82 31 f7 f6 e8 5d d8 1a f7 fb bf 01 00 00 00 52 53 ea f6 65 8b 05 43 9a 92 75 85 c0 74 02 5b c3 e8 20 80 8f
RSP: 0018:ffffc90003237c78 EFLAGS: 00000286
RAX: e0b14dde18847b00 RBX: ffff88802e0a1280 RCX: e0b14dde18847b00
RDX: dffffc0000000000 RSI: ffffffff8aaabce0 RDI: 0000000000000001
RBP: ffff88802e0a1518 R08: ffffffff8e4a212f R09: 1ffffffff1c94425
R10: dffffc0000000000 R11: fffffbfff1c94426 R12: 1ffff11005c142a3
R13: 0000000000000011 R14: dffffc0000000000 R15: 0000000000000000
spin_unlock_irq include/linux/spinlock.h:401 [inline]
get_signal+0x11f5/0x1400 kernel/signal.c:2905
arch_do_signal_or_restart+0x9c/0x7b0 arch/x86/kernel/signal.c:310
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f3e76b8f749
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:00007ffc2307a6c8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f3e76de5fa0 RCX: 00007f3e76b8f749
RDX: 0000200000000240 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f3e76c13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3e76de5fa0 R14: 00007f3e76de5fa0 R15: 0000000000000004
sched: RT throttling activated