rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P12792/1:b..l P6699/1:b..l rcu: (detected by 0, t=10502 jiffies, g=75389, q=32 ncpus=2) task:kworker/u4:15 state:R running task stack:22824 pid:6699 ppid:2 flags:0x00004000 Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x15ae/0x4660 kernel/sched/core.c:6701 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7011 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:lock_acquire+0xe/0x420 kernel/locking/lockdep.c:5722 Code: 65 8b 05 ed 32 9b 7e a9 00 ff ff 00 0f 95 c0 c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 f3 0f 1e fa 55 48 89 e5 41 57 41 56 41 55 <41> 54 53 48 83 e4 e0 48 81 ec e0 00 00 00 4c 89 4c 24 28 4c 89 44 RSP: 0018:ffffc90019ca7990 EFLAGS: 00000246 RAX: ffffffff8a525afb RBX: 0000000000000254 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8d131da0 RBP: ffffc90019ca79a8 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: fffffbfff1d190e6 R12: ffff88802ed2ffc0 R13: dffffc0000000000 R14: dffffc0000000000 R15: ffff88801ef292a0 rcu_lock_acquire include/linux/rcupdate.h:334 [inline] rcu_read_lock include/linux/rcupdate.h:786 [inline] batadv_iv_ogm_slide_own_bcast_window net/batman-adv/bat_iv_ogm.c:768 [inline] batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:848 [inline] batadv_iv_ogm_schedule+0x45c/0x1080 net/batman-adv/bat_iv_ogm.c:907 batadv_iv_send_outstanding_bat_ogm_packet+0x6ed/0x800 net/batman-adv/bat_iv_ogm.c:1804 process_one_work kernel/workqueue.c:2657 [inline] process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734 worker_thread+0xa5e/0xfe0 kernel/workqueue.c:2815 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 task:syz.3.1731 state:R running task stack:25608 pid:12792 ppid:8144 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x15ae/0x4660 kernel/sched/core.c:6701 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7011 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:692 RIP: 0010:kasan_check_range+0x1b9/0x290 mm/kasan/generic.c:-1 Code: f4 49 01 dc 4d 01 f3 49 8d 5c 24 07 4d 85 e4 49 0f 49 dc 48 83 e3 f8 49 29 dc 74 0e 41 80 3b 00 75 6b 49 ff c3 49 ff cc 75 f2 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 45 84 ff 0f 85 91 00 00 00 41 f7 RSP: 0018:ffffc9000461f6a8 EFLAGS: 00000256 RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff816885e7 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e8c8728 RBP: ffffc9000461f7f0 R08: ffffffff8e8c872f R09: 1ffffffff1d190e5 R10: dffffc0000000000 R11: fffffbfff1d190e6 R12: 0000000000000001 R13: ffffffff8d131da0 R14: fffffbfff1d190e6 R15: 1ffffffff1d190e5 instrument_atomic_read include/linux/instrumented.h:68 [inline] _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] cpumask_test_cpu include/linux/cpumask.h:504 [inline] cpu_online include/linux/cpumask.h:1082 [inline] trace_lock_acquire include/trace/events/lock.h:24 [inline] lock_acquire+0xb7/0x420 kernel/locking/lockdep.c:5725 rcu_lock_acquire include/linux/rcupdate.h:334 [inline] rcu_read_lock include/linux/rcupdate.h:786 [inline] __pte_offset_map+0x48/0x280 mm/pgtable-generic.c:287 __pte_offset_map_lock+0x47/0x1d0 mm/pgtable-generic.c:371 pte_offset_map_lock include/linux/mm.h:3016 [inline] finish_fault+0x718/0xce0 mm/memory.c:4492 do_read_fault mm/memory.c:4642 [inline] do_fault mm/memory.c:4775 [inline] do_pte_missing mm/memory.c:3689 [inline] handle_pte_fault mm/memory.c:5047 [inline] __handle_mm_fault mm/memory.c:5188 [inline] handle_mm_fault+0x3972/0x4a50 mm/memory.c:5353 faultin_page mm/gup.c:868 [inline] __get_user_pages+0x604/0x1580 mm/gup.c:1167 populate_vma_page_range+0x2c1/0x380 mm/gup.c:1593 __mm_populate+0x260/0x390 mm/gup.c:1696 mm_populate include/linux/mm.h:3383 [inline] vm_mmap_pgoff+0x2da/0x3f0 mm/util.c:561 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f7a9059e159 RSP: 002b:00007f7a914a4028 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007f7a90826090 RCX: 00007f7a9059e159 RDX: b635773f06ebbeef RSI: 0000000000b36000 RDI: 0000200000000000 RBP: 00007f7a90635024 R08: ffffffffffffffff R09: 0000000000000000 R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f7a90826128 R14: 00007f7a90826090 R15: 00007ffe47a84168 rcu: rcu_preempt kthread starved for 10562 jiffies! g75389 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:27432 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x15ae/0x4660 kernel/sched/core.c:6701 schedule+0xbd/0x170 kernel/sched/core.c:6775 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x30d/0x1590 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:pv_native_safe_halt+0xf/0x10 arch/x86/kernel/paravirt.c:148 Code: d9 19 02 c3 cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d a3 a5 38 00 fb f4 66 0f 1f 00 55 41 57 41 56 41 54 53 50 8b 2f eb 2c 89 cb 80 f9 RSP: 0018:ffffc90000187de0 EFLAGS: 000002c2 RAX: acb70dcbba2ce600 RBX: ffffffff81630c41 RCX: acb70dcbba2ce600 RDX: 0000000000000001 RSI: ffffffff8acacbe0 RDI: ffffffff8b1d3360 RBP: ffffc90000187f20 R08: ffff8880b8f36b6b R09: 1ffff110171e6d6d R10: dffffc0000000000 R11: ffffed10171e6d6e R12: 1ffff92000030fc8 R13: dffffc0000000000 R14: 1ffff110036ce780 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b31a23ffc CR3: 000000002b48b000 CR4: 00000000003506e0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:753 default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97 cpuidle_idle_call kernel/sched/idle.c:178 [inline] do_idle+0x221/0x5c0 kernel/sched/idle.c:302 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:401 start_secondary+0xee/0xf0 arch/x86/kernel/smpboot.c:323 secondary_startup_64_no_verify+0x179/0x17b