rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 GPs behind) idle=03dc/0/0x1 softirq=80229/80230 fqs=120
rcu: (detected by 1, t=10504 jiffies, g=108901, q=202 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:__rb_add include/linux/rbtree.h:229 [inline]
RIP: 0010:rb_add_linked include/linux/rbtree.h:281 [inline]
RIP: 0010:timerqueue_linked_add+0x2e/0x2e0 lib/timerqueue.c:96
Code: 55 41 57 41 56 41 55 41 54 53 48 83 ec 10 49 89 f5 48 89 fb 48 bd 00 00 00 00 00 fc ff df e8 59 2c e0 f5 48 89 d8 48 c1 e8 03 <80> 3c 28 00 74 08 48 89 df e8 e4 26 51 f6 4c 8b 33 4d 85 f6 0f 84
RSP: 0018:ffffc90000007d40 EFLAGS: 00000802
RAX: 1ffff110170850e3 RBX: ffff8880b8428718 RCX: ffffffff8fa8f000
RDX: 8000000001000001 RSI: 0000000001000001 RDI: ffff8880b8428718
RBP: dffffc0000000000 R08: 0000000001000001 R09: 1ffffffff22f5077
R10: dffffc0000000000 R11: fffffbfff22f5078 R12: 1ffff110170850d8
R13: ffff888082123300 R14: ffff888082123300 R15: ffff8880b8428644
FS: 0000000000000000(0000) GS:ffff888123aaa000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c34c0f6 CR3: 0000000056056000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000066
DR3: 0000000000004be6 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
enqueue_hrtimer+0x18e/0x2c0 kernel/time/hrtimer.c:1145
__run_hrtimer kernel/time/hrtimer.c:2091 [inline]
__hrtimer_run_queues+0x4ce/0xa10 kernel/time/hrtimer.c:2132
hrtimer_interrupt+0x4cd/0xaa0 kernel/time/hrtimer.c:2251
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline]
__sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1068
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1062
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64
Code: fb 87 02 c3 cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 03 68 1d 00 fb f4 bc 0b 03 00 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90
RSP: 0018:ffffffff8fa07ca0 EFLAGS: 00000246
RAX: 0000000000a1c733 RBX: ffffffff819bbc50 RCX: 8000000000000001
RDX: 0000000000000001 RSI: ffffffff8e46e275 RDI: ffffffff8c6e0480
RBP: ffffffff8fa07d78 R08: ffff8880b8433d9b R09: 1ffff110170867b3
R10: dffffc0000000000 R11: ffffed10170867b4 R12: 0000000000000000
R13: 1ffffffff1f51e00 R14: 1ffffffff1f40f9c R15: dffffc0000000000
arch_safe_halt arch/x86/kernel/process.c:767 [inline]
default_idle+0x9/0x20 arch/x86/kernel/process.c:768
default_idle_call+0x72/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:199 [inline]
do_idle+0x2e0/0x540 kernel/sched/idle.c:355
cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:454
rest_init+0x378/0x3a0 init/main.c:732
start_kernel+0x392/0x3e0 init/main.c:1190
x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x137/0x1b0 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x157
rcu: rcu_preempt kthread starved for 9904 jiffies! g108901 f0x0 RCU_GP_WAIT_FQS(5) ->state=R ->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:27496 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5583 [inline]
__schedule+0x17dd/0x5820 kernel/sched/core.c:7382
__schedule_loop kernel/sched/core.c:7459 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7474
schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x30c/0x1230 kernel/rcu/tree.c:2122
rcu_gp_kthread+0x9c/0x340 kernel/rcu/tree.c:2330
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 13460 Comm: syz.2.2331 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:csd_lock_wait kernel/smp.c:389 [inline]
RIP: 0010:csd_lock kernel/smp.c:422 [inline]
RIP: 0010:smp_call_function_many_cond+0x62d/0x1500 kernel/smp.c:970
Code: 89 fe 83 e6 01 31 ff e8 a1 64 0c 00 41 83 e7 01 75 07 e8 96 5f 0c 00 eb 3f f3 90 48 b8 00 00 00 00 00 fc ff df 41 0f b6 04 04 <84> c0 75 0f f7 03 01 00 00 00 74 1d e8 72 5f 0c 00 eb dc 89 d9 80
RSP: 0018:ffffc900061cf320 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffff8880b8443b28 RCX: ffff88802a0bbe80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900061cf470 R08: ffff88802a0bd41f R09: 1ffff11005417a83
R10: dffffc0000000000 R11: 0000000000000000 R12: 1ffff11017088765
R13: 0000000000000000 R14: ffff8880b8443b20 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff888123baa000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c301f69 CR3: 0000000056056000 CR4: 00000000003526f0
DR0: 00000000ffffffff DR1: 000000000000000a DR2: 4000000000000003
DR3: 0000000000000001 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
__flush_tlb_multi arch/x86/include/asm/paravirt.h:46 [inline]
flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline]
flush_tlb_mm_range+0x910/0x10b0 arch/x86/mm/tlb.c:1435
tlb_flush arch/x86/include/asm/tlb.h:23 [inline]
tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:509 [inline]
tlb_flush_mmu+0x1af/0xa30 mm/mmu_gather.c:423
tlb_finish_mmu+0xf4/0x220 mm/mmu_gather.c:549
free_ldt_pgtables+0x192/0x360 arch/x86/kernel/ldt.c:411
arch_exit_mmap arch/x86/include/asm/mmu_context.h:229 [inline]
exit_mmap+0x1bf/0x9f0 mm/mmap.c:1300
__mmput+0x118/0x420 kernel/fork.c:1193
exit_mm+0x18e/0x240 kernel/exit.c:586
do_exit+0x6a8/0x2360 kernel/exit.c:967
do_group_exit+0x22d/0x2f0 kernel/exit.c:1123
get_signal+0x1216/0x12c0 kernel/signal.c:3112
arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
exit_to_user_mode_loop+0x10e/0x770 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:343 [inline]
do_syscall_64+0x328/0x520 arch/x86/entry/syscall_64.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1d54b9f559
Code: Unable to access opcode bytes at 0x7f1d54b9f52f.
RSP: 002b:00007f1d55b0e0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 0000000000000001 RBX: 00007f1d54e25fa8 RCX: 00007f1d54b9f559
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f1d54e25fac
RBP: 00007f1d54e25fa0 R08: 3fffffffffffffff R09: 0000000000000000
R10: 0000000000000029 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1d54e26038 R14: 00007f1d54f4f960 R15: 00007f1d54f4fa48