dummy_hcd dummy_hcd.3: no ep configured for urb ffff888012596800 kcov: kcov_remote_start: handle = 100000000000004, context: softirq kcov: kcov_start: t = ffff888032070000, size = 262144, area = ffffc900022c2000 kcov: kcov_move_area: ffffc900170bf000 1048576 <= ffffc900022c2000 32 rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P10967/1:b..l P10946/1:b..l rcu: (detected by 0, t=10502 jiffies, g=136753, q=1725 ncpus=1) task:syz.3.1200 state:R running task stack:26920 pid:10946 tgid:10945 ppid:5627 task_flags:0x40054c flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5527 [inline] __schedule+0x17dd/0x5940 kernel/sched/core.c:7295 preempt_schedule_common+0x7f/0xd0 kernel/sched/core.c:7474 preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:201 [inline] _raw_spin_unlock+0x41/0x50 kernel/locking/spinlock.c:213 spin_unlock include/linux/spinlock.h:401 [inline] zap_pte_range mm/memory.c:2058 [inline] zap_pmd_range mm/memory.c:2114 [inline] zap_pud_range mm/memory.c:2142 [inline] zap_p4d_range mm/memory.c:2163 [inline] __zap_vma_range+0x40e1/0x4f70 mm/memory.c:2203 unmap_vmas+0x38b/0x550 mm/memory.c:2272 exit_mmap+0x293/0x9f0 mm/mmap.c:1315 __mmput+0x118/0x420 kernel/fork.c:1192 exit_mm+0x221/0x2d0 kernel/exit.c:614 do_exit+0x6cd/0x2360 kernel/exit.c:996 do_group_exit+0x22d/0x2f0 kernel/exit.c:1151 get_signal+0x1216/0x12c0 kernel/signal.c:3051 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:336 [inline] do_syscall_64+0x328/0x520 arch/x86/entry/syscall_64.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa6fed9e159 RSP: 002b:00007fa6ffb800e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007fa6ff025fa8 RCX: 00007fa6fed9e159 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fa6ff025fa8 RBP: 00007fa6ff025fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fa6ff026038 R14: 00007ffd48ac33d0 R15: 00007ffd48ac34b8 task:syz.9.1205 state:R running task stack:26920 pid:10967 tgid:10967 ppid:10964 task_flags:0x40044c flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5527 [inline] __schedule+0x17dd/0x5940 kernel/sched/core.c:7295 preempt_schedule_irq+0x4b/0x90 kernel/sched/core.c:7575 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:524 [inline] irqentry_exit+0x14f/0x910 kernel/entry/common.c:154 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:lock_acquire+0x232/0x350 kernel/locking/lockdep.c:5947 Code: ff ff ff e8 90 f9 52 0a f7 44 24 10 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 e2 f4 18 12 48 3b 44 24 50 75 33 fb 48 83 c4 58 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 ff 05 56 0a cc 48 8d 3d 27 8f fb RSP: 0018:ffffc9000552f228 EFLAGS: 00000286 RAX: 9ace8420d6857b00 RBX: 0000000000000000 RCX: 0000000000000046 RDX: 0000000077660e59 RSI: ffffffff8e82b24f RDI: ffffffff8c6f0580 RBP: ffff8880348a0000 R08: ffffffff817821df R09: 0000000000000000 R10: ffffc9000552f3b8 R11: fffff52000aa5e79 R12: ffffffff8ef5c7a0 R13: 0000000000000002 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:309 [inline] rcu_read_lock include/linux/rcupdate.h:849 [inline] class_rcu_constructor include/linux/rcupdate.h:1216 [inline] unwind_next_frame+0xac/0x2550 arch/x86/kernel/unwind_orc.c:495 __unwind_start+0x514/0x660 arch/x86/kernel/unwind_orc.c:787 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0xe3/0x150 arch/x86/kernel/stacktrace.c:24 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 __call_rcu_common kernel/rcu/tree.c:3181 [inline] call_rcu+0xee/0x8b0 kernel/rcu/tree.c:3301 slab_free_hook mm/slub.c:2712 [inline] slab_free mm/slub.c:6505 [inline] kmem_cache_free+0x471/0x650 mm/slub.c:6632 tear_down_vmas+0x31f/0x530 mm/mmap.c:1277 exit_mmap+0x4ca/0x9f0 mm/mmap.c:1335 __mmput+0x118/0x420 kernel/fork.c:1192 exit_mm+0x221/0x2d0 kernel/exit.c:614 do_exit+0x6cd/0x2360 kernel/exit.c:996 do_group_exit+0x22d/0x2f0 kernel/exit.c:1151 get_signal+0x1216/0x12c0 kernel/signal.c:3051 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:336 [inline] do_syscall_64+0x328/0x520 arch/x86/entry/syscall_64.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f13ed95e98e RSP: 002b:00007f13ee7e8e78 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6 RAX: 0000000000000000 RBX: 00007f13ee7e96c0 RCX: 00007f13ed95e98e RDX: 00007f13ee7e8ed0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f13eda3506b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f13edc26038 R14: 00007f13edc25fa0 R15: 00007ffc5c663f38 rcu: rcu_preempt kthread starved for 3553 jiffies! g136753 f0x0 RCU_GP_WAIT_FQS(5) ->state=R ->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:27496 pid:17 tgid:17 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5527 [inline] __schedule+0x17dd/0x5940 kernel/sched/core.c:7295 __schedule_loop kernel/sched/core.c:7372 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7387 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: 0 UID: 0 PID: 3230 Comm: kworker/R-bat_e Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Workqueue: bat_events batadv_dat_purge RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:211 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x47/0x80 kernel/locking/spinlock.c:221 Code: f7 e8 bd eb aa f5 f7 c3 00 02 00 00 74 05 e8 10 35 d7 f5 9c 58 a9 00 02 00 00 75 29 f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 54 00 9c f5 65 48 8b 05 dc 38 c3 07 48 85 c0 74 18 5b 41 5e c3 RSP: 0018:ffffc90000007b28 EFLAGS: 00000206 RAX: 0000000000000006 RBX: 0000000000000246 RCX: 8000000000000102 RDX: 0000000000000002 RSI: ffffffff8e59e74c RDI: 0000000000000001 RBP: ffffc90000007e40 R08: ffffffff909bb37f R09: 1ffffffff213766f R10: dffffc0000000000 R11: fffffbfff2137670 R12: 0000000000000246 R13: dffffc0000000000 R14: ffff88802951c000 R15: ffff8880296f5410 FS: 0000000000000000(0000) GS:ffff88812485b000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f13ed959270 CR3: 000000007e75e000 CR4: 00000000003526f0 Call Trace: spin_unlock_irqrestore include/linux/spinlock.h:425 [inline] dummy_timer+0x497b/0x4cf0 drivers/usb/gadget/udc/dummy_hcd.c:-1 __run_hrtimer kernel/time/hrtimer.c:2067 [inline] __hrtimer_run_queues+0x3bc/0xa10 kernel/time/hrtimer.c:2124 hrtimer_run_softirq+0x1e3/0x2e0 kernel/time/hrtimer.c:2141 handle_softirqs+0x226/0x860 kernel/softirq.c:645 do_softirq+0x77/0xd0 kernel/softirq.c:546 __local_bh_enable_ip+0x100/0x140 kernel/softirq.c:473 spin_unlock_bh include/linux/spinlock.h:407 [inline] __batadv_dat_purge net/batman-adv/distributed-arp-table.c:252 [inline] batadv_dat_purge+0x2d7/0x3c0 net/batman-adv/distributed-arp-table.c:271 process_one_work kernel/workqueue.c:3399 [inline] process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3482 rescuer_thread+0x7c5/0x10e0 kernel/workqueue.c:3706 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 dummy_hcd dummy_hcd.3: no ep configured for urb ffff888076a22b00 dummy_hcd dummy_hcd.3: no ep configured for urb ffff888076a22b00 dummy_hcd dummy_hcd.3: no ep configured for urb ffff888076a22b00