rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (1 ticks this GP) idle=21f/1/0x4000000000000000 softirq=17767/17771 fqs=4
(detected by 0, t=10503 jiffies, g=26397, q=36)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 6637 Comm: syz.2.617 Not tainted 5.15.185-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:__run_hrtimer kernel/time/hrtimer.c:1658 [inline]
RIP: 0010:__hrtimer_run_queues+0x2d6/0xc40 kernel/time/hrtimer.c:1754
Code: d0 cc 39 08 41 89 c6 31 ff 89 c6 e8 24 23 10 00 45 85 f6 0f 84 74 04 00 00 e8 b6 1f 10 00 eb 05 e8 af 1f 10 00 48 8b 7c 24 18 <e8> f5 32 00 00 48 8b 44 24 48 42 80 3c 38 00 4c 8b 74 24 68 74 08
RSP: 0018:ffffc90000dd0d20 EFLAGS: 00000006
RAX: ffffffff8167a26a RBX: ffff8880b912a300 RCX: ffff888026bfd940
RDX: 0000000000010000 RSI: 0000000000000001 RDI: ffff88801abe3b40
RBP: ffffc90000dd0e98 R08: dffffc0000000000 R09: ffff88801abe3b40
R10: ffffed100357c76b R11: 1ffff1100357c768 R12: ffff8880b912a310
R13: 1ffff11017225462 R14: 0000000000000001 R15: dffffc0000000000
FS: 00007ff232f076c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffaaaaaaaa CR3: 000000005f662000 CR4: 00000000003526e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
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:vcpu_enter_guest+0x5e71/0x70e0 arch/x86/kvm/x86.c:10032
Code: 00 48 89 df e8 40 75 0f 00 48 c7 c7 c0 57 02 8a e8 64 86 90 08 65 48 89 1d 5c 69 f1 7e e8 a7 e8 6c 00 fb 4c 8d b3 00 21 00 00 <4c> 89 f0 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 f7 e8 89 42 ac 00
RSP: 0018:ffffc9000345f5e0 EFLAGS: 00000282
RAX: be1a8ba2689ae800 RBX: ffff8880777c8000 RCX: be1a8ba2689ae800
RDX: dffffc0000000000 RSI: ffffffff8a0b11c0 RDI: ffffffff8a59a740
RBP: ffffc9000345fc20 R08: dffffc0000000000 R09: fffffbfff1ff363c
R10: fffffbfff1ff363c R11: 1ffffffff1ff363b R12: ffffff790761bb5c
R13: dffffc0000000000 R14: ffff8880777ca100 R15: ffff888026bfd940
vcpu_run arch/x86/kvm/x86.c:10162 [inline]
kvm_arch_vcpu_ioctl_run+0xdea/0x1f40 arch/x86/kvm/x86.c:10399
kvm_vcpu_ioctl+0x887/0xb80 virt/kvm/kvm_main.c:3894
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
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: 0033:0x7ff2350c0929
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:00007ff232f07038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ff2352e8080 RCX: 00007ff2350c0929
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000006
RBP: 00007ff235142b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007ff2352e8080 R15: 00007ffd7b055868
</TASK>
rcu: rcu_preempt kthread starved for 10485 jiffies! g26397 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:27464 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5030 [inline]
__schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
schedule+0x11b/0x1e0 kernel/sched/core.c:6459
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:
NMI backtrace for cpu 0
CPU: 0 PID: 5060 Comm: syz.4.200 Not tainted 5.15.185-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487
print_other_cpu_stall+0x10c8/0x1220 kernel/rcu/tree_stall.h:592
check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
rcu_pending kernel/rcu/tree.c:3932 [inline]
rcu_sched_clock_irq+0x831/0x1110 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:csd_lock_wait kernel/smp.c:440 [inline]
RIP: 0010:smp_call_function_single+0x212/0x490 kernel/smp.c:758
Code: 48 44 89 f6 83 e6 01 31 ff e8 0a 6b 0b 00 41 83 e6 01 49 bc 00 00 00 00 00 fc ff df 75 0a e8 95 67 0b 00 e9 a3 00 00 00 f3 90 <f7> 44 24 48 01 00 00 00 0f 84 8e 00 00 00 e8 7b 67 0b 00 eb e9 e8
RSP: 0018:ffffc9000321f1a0 EFLAGS: 00000246
RAX: ffffffff816c5aa5 RBX: 0000000000000000 RCX: 0000000000080000
RDX: ffffc9000d5b1000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc9000321f290 R08: dffffc0000000000 R09: ffffed1017227679
R10: ffffed1017227679 R11: 1ffff11017227678 R12: dffffc0000000000
R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff92000643e38
rcu_barrier+0x25d/0x4b0 kernel/rcu/tree.c:4078
netdev_wait_allrefs net/core/dev.c:10592 [inline]
netdev_run_todo+0x5f2/0xa40 net/core/dev.c:10681
rtnl_unlock net/core/rtnetlink.c:112 [inline]
rtnetlink_rcv_msg+0x9c0/0xe60 net/core/rtnetlink.c:5651
netlink_rcv_skb+0x1e0/0x430 net/netlink/af_netlink.c:2489
netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline]
netlink_unicast+0x77c/0x920 net/netlink/af_netlink.c:1337
netlink_sendmsg+0x8ab/0xbc0 net/netlink/af_netlink.c:1905
sock_sendmsg_nosec net/socket.c:704 [inline]
__sock_sendmsg net/socket.c:716 [inline]
____sys_sendmsg+0x5a2/0x8c0 net/socket.c:2436
___sys_sendmsg+0x1f0/0x260 net/socket.c:2490
__sys_sendmsg net/socket.c:2519 [inline]
__do_sys_sendmsg net/socket.c:2528 [inline]
__se_sys_sendmsg+0x190/0x250 net/socket.c:2526
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: 0033:0x7fcf435f8929
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:00007fcf41460038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fcf4381ffa0 RCX: 00007fcf435f8929
RDX: 0000000000000850 RSI: 00002000000002c0 RDI: 0000000000000004
RBP: 00007fcf4367ab39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fcf4381ffa0 R15: 00007ffc7035cb08
</TASK>