rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P13/1:b..l P8235/1:b..l P11113/1:b..l P8142/1:b..l rcu: (detected by 0, t=10502 jiffies, g=40493, q=743 ncpus=2) task:udevd state:R running task stack:24904 pid:8142 tgid:8142 ppid:5220 task_flags:0x40014c flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6961 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7288 irqentry_exit+0x36/0x90 kernel/entry/common.c:197 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_release+0x183/0x2f0 kernel/locking/lockdep.c:5893 Code: 0f c1 05 b8 4c 3f 12 83 f8 01 0f 85 1d 01 00 00 9c 58 f6 c4 02 0f 85 08 01 00 00 41 f7 c5 00 02 00 00 74 01 fb 48 8b 44 24 10 <65> 48 2b 05 cd 0a 3f 12 0f 85 58 01 00 00 48 83 c4 18 5b 41 5c 41 RSP: 0018:ffffc900042ef710 EFLAGS: 00000206 RAX: 3c98761be0997100 RBX: ffffffff8e5c15a0 RCX: ffffc900042ef71c RDX: 0000000000000001 RSI: ffffffff8de2d8f8 RDI: ffffffff8c163400 RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 00000000000061ee R12: ffffffff816af8a4 R13: 0000000000000202 R14: ffff888026d30000 R15: 0000000000000002 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:871 [inline] class_rcu_destructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0x3f9/0x20a0 arch/x86/kernel/unwind_orc.c:479 __unwind_start+0x45f/0x7f0 arch/x86/kernel/unwind_orc.c:758 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0x73/0x100 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:548 slab_free_hook mm/slub.c:2383 [inline] slab_free mm/slub.c:4695 [inline] kmem_cache_free+0x15a/0x4d0 mm/slub.c:4797 exit_mmap+0x511/0xb90 mm/mmap.c:1305 __mmput+0x12a/0x410 kernel/fork.c:1129 mmput+0x62/0x70 kernel/fork.c:1152 exit_mm kernel/exit.c:582 [inline] do_exit+0x7c7/0x2bf0 kernel/exit.c:949 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102 __do_sys_exit_group kernel/exit.c:1113 [inline] __se_sys_exit_group kernel/exit.c:1111 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1111 x64_sys_call+0x14fa/0x1720 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f29728f16c5 RSP: 002b:00007ffdba1705f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 000055cc661e6770 RCX: 00007f29728f16c5 RDX: 00000000000000e7 RSI: fffffffffffffe68 RDI: 0000000000000000 RBP: 000055cc65d122c0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffdba170640 R14: 0000000000000000 R15: 0000000000000000 task:syz.5.1338 state:R running task stack:26264 pid:11113 tgid:11113 ppid:6589 task_flags:0x40044c flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6961 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:7145 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] zap_pte_range mm/memory.c:1756 [inline] zap_pmd_range mm/memory.c:1818 [inline] zap_pud_range mm/memory.c:1847 [inline] zap_p4d_range mm/memory.c:1868 [inline] unmap_page_range+0xf77/0x42c0 mm/memory.c:1889 unmap_single_vma.constprop.0+0x153/0x240 mm/memory.c:1932 unmap_vmas+0x218/0x470 mm/memory.c:1976 exit_mmap+0x1b9/0xb90 mm/mmap.c:1280 __mmput+0x12a/0x410 kernel/fork.c:1129 mmput+0x62/0x70 kernel/fork.c:1152 exit_mm kernel/exit.c:582 [inline] do_exit+0x7c7/0x2bf0 kernel/exit.c:949 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102 get_signal+0x2673/0x26d0 kernel/signal.c:3034 arch_do_signal_or_restart+0x8f/0x7d0 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x84/0x110 kernel/entry/common.c:40 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x41c/0x4e0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f860218eec9 RSP: 002b:00007ffe7fd5fc18 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: 0000000000000000 RBX: 000000000006e172 RCX: 00007f860218eec9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f86023e609c RBP: 0000000000000032 R08: 00007f8603095000 R09: 0000000e7fd5ff0f R10: 00007ffe7fd5fd10 R11: 0000000000000246 R12: 00007f86023e609c R13: 00007ffe7fd5fd10 R14: 000000000006e1a4 R15: 00007ffe7fd5fd30 task:udevd state:R running task stack:24712 pid:8235 tgid:8235 ppid:5220 task_flags:0x40014c flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6961 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7288 irqentry_exit+0x36/0x90 kernel/entry/common.c:197 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x62/0x350 kernel/locking/lockdep.c:5872 Code: 05 3f 12 83 f8 07 0f 87 bc 02 00 00 89 c0 48 0f a3 05 e2 9c 13 0f 0f 82 74 02 00 00 8b 35 9a ce 13 0f 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 39 05 3f 12 0f 85 c7 02 00 00 48 83 c4 RSP: 0018:ffffc90018957708 EFLAGS: 00000206 RAX: 0000000000000046 RBX: ffffffff8e5c15a0 RCX: 00000000d3addaf6 RDX: 0000000000000000 RSI: ffffffff8de2d8f8 RDI: ffffffff8c163400 RBP: 0000000000000002 R08: 328b0d0cf36cb5da R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] is_bpf_text_address+0x36/0x1a0 kernel/bpf/core.c:776 kernel_text_address kernel/extable.c:125 [inline] kernel_text_address+0x8d/0x100 kernel/extable.c:94 __kernel_text_address+0xd/0x40 kernel/extable.c:79 unwind_get_return_address+0x59/0xa0 arch/x86/kernel/unwind_orc.c:369 arch_stack_walk+0xa6/0x100 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:243 [inline] __kasan_slab_free+0x60/0x70 mm/kasan/common.c:275 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2422 [inline] slab_free mm/slub.c:4695 [inline] kfree+0x2b4/0x4d0 mm/slub.c:4894 vma_numab_state_free include/linux/mm.h:667 [inline] vm_area_free+0x94/0x260 mm/vma_init.c:147 exit_mmap+0x511/0xb90 mm/mmap.c:1305 __mmput+0x12a/0x410 kernel/fork.c:1129 mmput+0x62/0x70 kernel/fork.c:1152 exit_mm kernel/exit.c:582 [inline] do_exit+0x7c7/0x2bf0 kernel/exit.c:949 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102 __do_sys_exit_group kernel/exit.c:1113 [inline] __se_sys_exit_group kernel/exit.c:1111 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1111 x64_sys_call+0x14fa/0x1720 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f29728f16c5 RSP: 002b:00007ffdba1705f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 000055cc65d124c0 RCX: 00007f29728f16c5 RDX: 00000000000000e7 RSI: fffffffffffffe68 RDI: 0000000000000000 RBP: 000055cc65d122c0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffdba170640 R14: 0000000000000000 R15: 0000000000000000 task:kworker/u8:1 state:R running task stack:23560 pid:13 tgid:13 ppid:2 task_flags:0x4208160 flags:0x00004000 Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6961 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7288 irqentry_exit+0x36/0x90 kernel/entry/common.c:197 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x62/0x350 kernel/locking/lockdep.c:5872 Code: 05 3f 12 83 f8 07 0f 87 bc 02 00 00 89 c0 48 0f a3 05 e2 9c 13 0f 0f 82 74 02 00 00 8b 35 9a ce 13 0f 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 39 05 3f 12 0f 85 c7 02 00 00 48 83 c4 RSP: 0018:ffffc90000127a48 EFLAGS: 00000206 RAX: 0000000000000046 RBX: ffffffff8e5c15a0 RCX: 00000000482b3777 RDX: 0000000000000000 RSI: ffffffff8de2d8f8 RDI: ffffffff8c163400 RBP: 0000000000000002 R08: 515094b9a20698f1 R09: 0000000000000000 R10: 0000000000000003 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] batadv_iv_ogm_slide_own_bcast_window net/batman-adv/bat_iv_ogm.c:762 [inline] batadv_iv_ogm_schedule_buff+0x5d0/0x14c0 net/batman-adv/bat_iv_ogm.c:834 batadv_iv_ogm_schedule net/batman-adv/bat_iv_ogm.c:874 [inline] batadv_iv_ogm_schedule net/batman-adv/bat_iv_ogm.c:867 [inline] batadv_iv_send_outstanding_bat_ogm_packet+0x329/0x920 net/batman-adv/bat_iv_ogm.c:1714 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:463 ret_from_fork+0x56a/0x730 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: rcu_preempt kthread starved for 10431 jiffies! g40493 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:27784 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:7058 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2285 kthread+0x3c2/0x780 kernel/kthread.c:463 ret_from_fork+0x56a/0x730 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82 Code: 3d 61 02 c3 cc cc cc cc 0f 1f 00 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 d3 16 15 00 fb f4 cc 09 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffc90000197df8 EFLAGS: 000002c2 RAX: 0000000001b37e65 RBX: 0000000000000001 RCX: ffffffff8b94fb49 RDX: 0000000000000000 RSI: ffffffff8de52e89 RDI: ffffffff8c163400 RBP: ffffed1003c5d488 R08: 0000000000000001 R09: ffffed10170a6655 R10: ffff8880b85332ab R11: 0000000000000000 R12: 0000000000000001 R13: ffff88801e2ea440 R14: ffffffff90ab7790 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881247b2000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc247e191c1 CR3: 0000000034db0000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:757 default_idle_call+0x6d/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:190 [inline] do_idle+0x391/0x510 kernel/sched/idle.c:330 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:428 start_secondary+0x21d/0x2b0 arch/x86/kernel/smpboot.c:315 common_startup_64+0x13e/0x148