rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P14613/1:b..l rcu: (detected by 0, t=10502 jiffies, g=126545, q=1600 ncpus=1) task:syz.8.1956 state:R running task stack:27216 pid:14613 tgid:14613 ppid:13697 task_flags:0x40004c flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7556 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x910 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:lock_acquire+0x221/0x350 kernel/locking/lockdep.c:5872 Code: ff ff ff e8 11 8c 31 0a f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 9b 56 cb 11 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 6b 87 6d ff cc 48 8d 3d d8 74 b8 RSP: 0018:ffffc90004a1f3e0 EFLAGS: 00000282 RAX: 17e0088152598700 RBX: 0000000000000000 RCX: 0000000000000046 RDX: 00000000270d408f RSI: ffffffff8e4b3e80 RDI: ffffffff8c4bdc80 RBP: ffffffff8177827f R08: ffffffff8177827f R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8eb59d60 R12: 0000000000000002 R13: ffffffff8eb59d60 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:300 [inline] rcu_read_lock include/linux/rcupdate.h:840 [inline] class_rcu_constructor include/linux/rcupdate.h:1183 [inline] unwind_next_frame+0xac/0x2550 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556 slab_free_hook mm/slub.c:2638 [inline] slab_free mm/slub.c:6377 [inline] kmem_cache_free+0x44f/0x650 mm/slub.c:6504 anon_vma_free mm/rmap.c:137 [inline] __put_anon_vma+0x12b/0x2d0 mm/rmap.c:2917 put_anon_vma mm/internal.h:215 [inline] unlink_anon_vmas+0x589/0x730 mm/rmap.c:536 free_pgtables+0x836/0xb70 mm/memory.c:414 exit_mmap+0x4aa/0x9f0 mm/mmap.c:1312 __mmput+0x118/0x420 kernel/fork.c:1187 exit_mm+0x221/0x2d0 kernel/exit.c:615 do_exit+0x6cd/0x2360 kernel/exit.c:997 __do_sys_exit kernel/exit.c:1119 [inline] __se_sys_exit kernel/exit.c:1117 [inline] __x64_sys_exit+0x40/0x40 kernel/exit.c:1117 x64_sys_call+0x224e/0x2250 arch/x86/include/generated/asm/syscalls_64.h:61 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3e36f9e0d9 RSP: 002b:00007f3e37e3efd8 EFLAGS: 00000246 ORIG_RAX: 000000000000003c RAX: ffffffffffffffda RBX: 00007f3e37225fa0 RCX: 00007f3e36f9e0d9 RDX: 00007f3e37e3f9c8 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f3e37035024 R08: 0000000000000000 R09: 0000200000000400 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f3e37226038 R14: 00007f3e37225fa0 R15: 00007ffc1d2bbee8 rcu: rcu_preempt kthread starved for 2006 jiffies! g126545 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:28104 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325 kthread+0x388/0x470 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: 0 UID: 0 PID: 7896 Comm: kworker/R-bond1 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 Workqueue: 0x0 (bond1) RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x47/0x80 kernel/locking/spinlock.c:198 Code: f7 e8 ad 5d cc f5 f7 c3 00 02 00 00 74 05 e8 50 3e f8 f5 9c 58 a9 00 02 00 00 75 27 f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 44 71 bd f5 65 8b 05 fd 0f 97 07 85 c0 74 18 5b 41 5e e9 cc 40 RSP: 0018:ffffc90000007b08 EFLAGS: 00000206 RAX: 0000000000000002 RBX: 0000000000000246 RCX: 0000000080000101 RDX: 0000000000000002 RSI: ffffffff8e22f03a RDI: 0000000000000001 RBP: ffffc90000007e10 R08: ffffffff90579f37 R09: 1ffffffff20af3e6 R10: dffffc0000000000 R11: fffffbfff20af3e7 R12: 0000000000000246 R13: dffffc0000000000 R14: ffff8880299a8000 R15: ffff888029542410 FS: 0000000000000000(0000) GS:ffff888124f3f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fac095ce0f1 CR3: 000000005a379000 CR4: 0000000000350ef0 Call Trace: spin_unlock_irqrestore include/linux/spinlock.h:408 [inline] dummy_timer+0x497b/0x4cf0 drivers/usb/gadget/udc/dummy_hcd.c:-1 __run_hrtimer kernel/time/hrtimer.c:2032 [inline] __hrtimer_run_queues+0x3bc/0xa10 kernel/time/hrtimer.c:2096 hrtimer_run_softirq+0x17a/0x240 kernel/time/hrtimer.c:2113 handle_softirqs+0x225/0x840 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0xca/0x220 kernel/softirq.c:735 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:lock_acquire+0x221/0x350 kernel/locking/lockdep.c:5872 Code: ff ff ff e8 11 8c 31 0a f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 9b 56 cb 11 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 6b 87 6d ff cc 48 8d 3d d8 74 b8 RSP: 0018:ffffc900044afa80 EFLAGS: 00000282 RAX: 76442c251bc36f00 RBX: 0000000000000000 RCX: 0000000000000046 RDX: 000000005cc09c8b RSI: ffffffff8e4b3e80 RDI: ffffffff8c4bdc80 RBP: ffffffff8bd57840 R08: ffffffff8bd57840 R09: 0000000000000000 R10: 0000000000008000 R11: ffffffff8ea0ea80 R12: 0000000000000000 R13: ffffffff8ea0ea80 R14: 0000000000000001 R15: 0000000000000246 sched_submit_work kernel/sched/core.c:7269 [inline] schedule+0xb0/0x2b0 kernel/sched/core.c:7325 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383 __mutex_lock_common kernel/locking/mutex.c:726 [inline] __mutex_lock+0x7bf/0x1550 kernel/locking/mutex.c:821 worker_attach_to_pool+0x31/0x390 kernel/workqueue.c:2737 rescuer_thread+0x335/0x10b0 kernel/workqueue.c:3622 kthread+0x388/0x470 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