rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (0 ticks this GP) idle=0b94/1/0x4000000000000000 softirq=279623/279623 fqs=10
rcu: (detected by 0, t=10502 jiffies, g=188285, q=180 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 1249 Comm: syz.8.9085 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:num_possible_cpus include/linux/cpumask.h:1222 [inline]
RIP: 0010:mm_get_cid kernel/sched/sched.h:3782 [inline]
RIP: 0010:sched_mm_cid_fork+0x56c/0xc80 kernel/sched/core.c:10645
Code: 00 00 0f b6 c0 41 29 c6 4c 89 e3 e9 64 ff ff ff 49 c7 c5 c8 b4 f7 8d 49 c1 ed 03 eb 0b 44 89 e0 f7 d8 0f 81 2a fd ff ff f3 90 <48> b8 00 00 00 00 00 fc ff df 41 0f b6 44 05 00 84 c0 75 50 44 8b
RSP: 0018:ffffc90005187c78 EFLAGS: 00000887
RAX: 0000000080000000 RBX: 0000000000000002 RCX: dffffc0000000000
RDX: dffffc0000000000 RSI: 0000000000000002 RDI: ffff88804b8b48d0
RBP: ffff88804b8b48d0 R08: 1ffff110097167c9 R09: 0000000000000000
R10: ffff88804b8b3f8c R11: fffff52000a30f80 R12: 0000000080000000
R13: 1ffffffff1bef699 R14: 0000000000000002 R15: ffff88804b8b3d40
FS: 00007f87df1f66c0(0000) GS:ffff8881257f3000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000004c53a000 CR4: 00000000003526f0
Call Trace:
bprm_execve+0xda1/0x1410 fs/exec.c:1776
do_execveat_common+0x50f/0x690 fs/exec.c:1859
do_execveat fs/exec.c:1944 [inline]
__do_sys_execveat fs/exec.c:2018 [inline]
__se_sys_execveat fs/exec.c:2012 [inline]
__x64_sys_execveat+0xc4/0xe0 fs/exec.c:2012
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f87e0f9aeb9
Code: 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 01 48
RSP: 002b:00007f87df1f6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000142
RAX: ffffffffffffffda RBX: 00007f87e1215fa0 RCX: 00007f87e0f9aeb9
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000004
RBP: 00007f87e1008c1f R08: 0000000000001000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f87e1216038 R14: 00007f87e1215fa0 R15: 00007f87e133fa48
rcu: rcu_preempt kthread starved for 10482 jiffies! g188285 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:27448 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5260 [inline]
__schedule+0x1522/0x51d0 kernel/sched/core.c:6867
__schedule_loop kernel/sched/core.c:6949 [inline]
schedule+0x164/0x360 kernel/sched/core.c:6964
schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x312/0x1560 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:2285
kthread+0x726/0x8b0 kernel/kthread.c:463
ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 1257 Comm: syz.1.9088 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x47/0x80 kernel/locking/spinlock.c:194
Code: f7 e8 5d 36 07 f6 f7 c3 00 02 00 00 74 05 e8 30 97 32 f6 9c 58 a9 00 02 00 00 75 27 f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 e4 01 f9 f5 65 8b 05 4d 14 59 07 85 c0 74 18 5b 41 5e c3 cc cc
RSP: 0018:ffffc90000007a88 EFLAGS: 00000206
RAX: 0000000000000006 RBX: 0000000000000246 RCX: 0000000000000103
RDX: 0000000000000003 RSI: ffffffff8dcc9ce4 RDI: 0000000000000001
RBP: ffffc90000007d70 R08: ffffffff8fef2077 R09: 1ffffffff1fde40e
R10: dffffc0000000000 R11: fffffbfff1fde40f R12: dffffc0000000000
R13: 000000000000d000 R14: ffff888141be4000 R15: ffff8880285fc470
FS: 00007faf97e106c0(0000) GS:ffff8881256f3000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b30224220 CR3: 0000000089dbc000 CR4: 00000000003526f0
Call Trace:
spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
dummy_timer+0x44a2/0x45d0 drivers/usb/gadget/udc/dummy_hcd.c:-1
__run_hrtimer kernel/time/hrtimer.c:1777 [inline]
__hrtimer_run_queues+0x527/0xc30 kernel/time/hrtimer.c:1841
hrtimer_run_softirq+0x182/0x5a0 kernel/time/hrtimer.c:1858
handle_softirqs+0x22a/0x7c0 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723
irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_single+0x399/0x580 kernel/smp.c:687
Code: 33 44 89 f6 83 e6 01 31 ff e8 73 f1 0b 00 41 83 e6 01 75 11 e8 28 ed 0b 00 4d 89 fe eb 3f e8 1e ed 0b 00 eb 3c 4d 89 fe f3 90 <43> 0f b6 04 2c 84 c0 75 0f f7 03 01 00 00 00 74 1d e8 01 ed 0b 00
RSP: 0018:ffffc90004676220 EFLAGS: 00000246
RAX: ffffffff81b88d1f RBX: ffffc90004676268 RCX: 0000000000080000
RDX: ffffc9000e831000 RSI: 000000000007ffff RDI: 0000000000080000
RBP: ffffc90004676300 R08: ffffffff8fef2077 R09: 1ffffffff1fde40e
R10: dffffc0000000000 R11: ffffffff8172fff0 R12: 1ffff920008cec4d
R13: dffffc0000000000 R14: 1ffff920008cec48 R15: 1ffff920008cec48
loaded_vmcs_clear arch/x86/kvm/vmx/vmx.c:870 [inline]
vmx_vcpu_load_vmcs+0xcd/0x5e0 arch/x86/kvm/vmx/vmx.c:1527
vmx_vcpu_load+0x1b0/0x260 arch/x86/kvm/vmx/vmx.c:1585
kvm_arch_vcpu_load+0x25d/0xa50 arch/x86/kvm/x86.c:5167
kvm_sched_in+0x7c/0xe0 virt/kvm/kvm_main.c:6405
__fire_sched_in_preempt_notifiers kernel/sched/core.c:4819 [inline]
fire_sched_in_preempt_notifiers kernel/sched/core.c:4825 [inline]
finish_task_switch+0x859/0x920 kernel/sched/core.c:5128
context_switch kernel/sched/core.c:5263 [inline]
__schedule+0x152a/0x51d0 kernel/sched/core.c:6867
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7194
irqentry_exit+0x597/0x620 kernel/entry/common.c:216
asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:put_cpu_partial+0x1db/0x280 mm/slub.c:3960
Code: 5b 41 5c 41 5d 41 5e 41 5f 5d e9 90 e9 ff ff 90 0f 0b 90 e9 15 ff ff ff e8 e2 3d 75 09 41 f7 c5 00 02 00 00 74 cf fb 4d 85 ff <75> ce 5b 41 5c 41 5d 41 5e 41 5f 5d e9 84 23 78 09 cc e8 be 3d 75
RSP: 0018:ffffc90004676898 EFLAGS: 00000246
RAX: 0000000000000006 RBX: ffff88813fe27140 RCX: 0000000000000046
RDX: 0000000000000007 RSI: ffffffff8dcc9ce4 RDI: ffffffff8c073b00
RBP: 0000000000000001 R08: ffffffff8fef2077 R09: 1ffffffff1fde40e
R10: dffffc0000000000 R11: fffffbfff1fde40f R12: 0000000000000001
R13: 0000000000000246 R14: ffff8880b873f190 R15: 0000000000000000
__slab_free+0x294/0x320 mm/slub.c:5956
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4953 [inline]
slab_alloc_node mm/slub.c:5263 [inline]
kmem_cache_alloc_noprof+0x370/0x6e0 mm/slub.c:5270
ptlock_alloc+0x20/0x70 mm/memory.c:7380
ptlock_init include/linux/mm.h:3284 [inline]
pagetable_pte_ctor include/linux/mm.h:3338 [inline]
__pte_alloc_one_noprof include/asm-generic/pgalloc.h:79 [inline]
pte_alloc_one+0x7a/0x370 arch/x86/mm/pgtable.c:18
__do_fault+0xd1/0x390 mm/memory.c:5318
do_read_fault mm/memory.c:5758 [inline]
do_fault mm/memory.c:5892 [inline]
do_pte_missing+0x21a2/0x37a0 mm/memory.c:4404
handle_pte_fault mm/memory.c:6276 [inline]
__handle_mm_fault mm/memory.c:6414 [inline]
handle_mm_fault+0x1b8c/0x32a0 mm/memory.c:6583
faultin_page mm/gup.c:1126 [inline]
__get_user_pages+0x165b/0x29d0 mm/gup.c:1428
__get_user_pages_locked mm/gup.c:1692 [inline]
get_user_pages_unlocked+0x1e2/0x710 mm/gup.c:2681
hva_to_pfn_slow virt/kvm/kvm_main.c:2926 [inline]
hva_to_pfn+0x34d/0xe00 virt/kvm/kvm_main.c:3022
__kvm_faultin_pfn+0xaa/0x100 virt/kvm/kvm_main.c:3090
__kvm_mmu_faultin_pfn arch/x86/kvm/mmu/mmu.c:4600 [inline]
kvm_mmu_faultin_pfn+0x735/0x1590 arch/x86/kvm/mmu/mmu.c:4730
kvm_tdp_mmu_page_fault arch/x86/kvm/mmu/mmu.c:4898 [inline]
kvm_tdp_page_fault+0x273/0x370 arch/x86/kvm/mmu/mmu.c:4921
kvm_mmu_do_page_fault+0x33d/0x690 arch/x86/kvm/mmu/mmu_internal.h:381
kvm_arch_async_page_ready+0x4f9/0x670 arch/x86/kvm/mmu/mmu.c:4549
kvm_check_async_pf_completion+0x20c/0x3c0 virt/kvm/async_pf.c:165
vcpu_enter_guest arch/x86/kvm/x86.c:11211 [inline]
vcpu_run+0x2821/0x7920 arch/x86/kvm/x86.c:11652
kvm_arch_vcpu_ioctl_run+0x11e6/0x20d0 arch/x86/kvm/x86.c:11997
kvm_vcpu_ioctl+0xa62/0xfd0 virt/kvm/kvm_main.c:4492
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7faf96f9aeb9
Code: 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 01 48
RSP: 002b:00007faf97e10028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007faf97215fa0 RCX: 00007faf96f9aeb9
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000006
RBP: 00007faf97008c1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007faf97216038 R14: 00007faf97215fa0 R15: 00007faf9733fa48