rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5610/1:b..l rcu: (detected by 0, t=10502 jiffies, g=59409, q=1035 ncpus=1) task:syz-executor state:R running task stack:23624 pid:5610 tgid:5610 ppid:5607 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7556 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:468 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x205/0xa00 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:lock_acquire+0x5e/0x370 kernel/locking/lockdep.c:5872 Code: 05 fb 2d 7e 12 83 f8 07 0f 87 da 00 00 00 48 0f a3 05 86 7b 3c 0f 0f 82 ac 02 00 00 8b 35 4e af 3c 0f 85 f6 0f 85 c7 00 00 00 <48> 8b 44 24 30 65 48 2b 05 9d 2d 7e 12 0f 85 ec 02 00 00 48 83 c4 RSP: 0018:ffffc900024ff7c8 EFLAGS: 00000206 RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8e17f6ed RDI: ffffffff8c401580 RBP: ffffffff8ebe8180 R08: 00000000b94c84b0 R09: 0000000000000007 R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 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+0xd1/0x2090 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 save_stack+0x162/0x1e0 mm/page_owner.c:165 __reset_page_owner+0x84/0x190 mm/page_owner.c:320 reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1406 [inline] __free_frozen_pages+0x79f/0x1090 mm/page_alloc.c:2950 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x47/0xf0 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286 __kasan_kmalloc+0x8a/0xb0 mm/kasan/common.c:406 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5334 [inline] __kmalloc_noprof+0x322/0x820 mm/slub.c:5359 _kmalloc_noprof include/linux/slab.h:992 [inline] _kzalloc_noprof include/linux/slab.h:1309 [inline] lsm_blob_alloc+0x68/0x90 security/security.c:218 lsm_sock_alloc security/security.c:4478 [inline] security_sk_alloc+0x2d/0x290 security/security.c:4494 sk_prot_alloc+0x1d1/0x2a0 net/core/sock.c:2255 sk_alloc+0x36/0xe80 net/core/sock.c:2308 inet_create net/ipv4/af_inet.c:333 [inline] inet_create+0x3a0/0x1060 net/ipv4/af_inet.c:259 __sock_create+0x339/0x860 net/socket.c:1651 sock_create net/socket.c:1709 [inline] __sys_socket_create net/socket.c:1746 [inline] __sys_socket+0x14d/0x260 net/socket.c:1793 __do_sys_socket net/socket.c:1807 [inline] __se_sys_socket net/socket.c:1805 [inline] __x64_sys_socket+0x72/0xb0 net/socket.c:1805 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0ae219f707 RSP: 002b:00007ffdf74acd48 EFLAGS: 00000206 ORIG_RAX: 0000000000000029 RAX: ffffffffffffffda RBX: 00007f0ae23ea460 RCX: 00007f0ae219f707 RDX: 0000000000000006 RSI: 0000000000000001 RDI: 0000000000000002 RBP: 00007ffdf74ad46c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000190 R13: 00000000000927c0 R14: 0000000000000000 R15: 00007ffdf74ad4c0 rcu: rcu_preempt kthread starved for 6125 jiffies! g59409 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:27880 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0xdd/0x2c0 kernel/sched/core.c:7326 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2325 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 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: 3225 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 07/16/2026 Workqueue: bat_events batadv_tt_purge RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:198 Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 56 20 28 f6 48 89 df e8 de 6f 28 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 a5 7f 17 f6 65 8b 05 ee 48 a6 08 85 c0 74 16 5b RSP: 0018:ffffc90000007c68 EFLAGS: 00000246 RAX: 0000000000000006 RBX: ffff88802a6bc000 RCX: 0000000000000004 RDX: 0000000000000000 RSI: ffffffff8e1a55a5 RDI: ffffffff8c401580 RBP: 0000000000000246 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffff8881a9b03310 R13: ffff8881a9b03308 R14: ffff88802a9034a3 R15: ffff88802a903410 FS: 0000000000000000(0000) GS:ffff888123dde000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000555569aa14e8 CR3: 000000001f6a1000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: spin_unlock_irqrestore include/linux/spinlock.h:408 [inline] dummy_timer+0x1db5/0x36c0 drivers/usb/gadget/udc/dummy_hcd.c:2022 __run_hrtimer kernel/time/hrtimer.c:2032 [inline] __hrtimer_run_queues+0x462/0x9c0 kernel/time/hrtimer.c:2096 hrtimer_run_softirq+0x17d/0x2c0 kernel/time/hrtimer.c:2113 handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622 do_softirq kernel/softirq.c:523 [inline] do_softirq+0xac/0xe0 kernel/softirq.c:510 __local_bh_enable_ip+0xf8/0x120 kernel/softirq.c:450 spin_unlock_bh include/linux/spinlock.h:396 [inline] batadv_tt_local_purge+0x21c/0x3d0 net/batman-adv/translation-table.c:1366 batadv_tt_purge+0x8b/0xbd0 net/batman-adv/translation-table.c:3565 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322 process_scheduled_works kernel/workqueue.c:3405 [inline] rescuer_thread+0x905/0x14a0 kernel/workqueue.c:3629 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245