rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (0 ticks this GP) idle=891c/1/0x4000000000000000 softirq=158006/158006 fqs=0 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P36/1:b..l rcu: (detected by 1, t=10502 jiffies, g=104985, q=158 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 9210 Comm: kworker/u8:12 Not tainted 6.17.0-rc1-syzkaller-00211-g90d970cade8e #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Workqueue: kvfree_rcu_reclaim kfree_rcu_work RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x98/0x110 kernel/locking/spinlock.c:194 Code: 21 f6 4c 89 f7 e8 c8 04 22 f6 f7 c3 00 02 00 00 74 05 e8 8b 56 4b f6 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 <75> 4f f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 e8 f3 fd 13 f6 65 RSP: 0018:ffffc90000007be0 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 0000000000000012 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffff99c851d8 RBP: ffffc90000007c78 R08: ffffffff99c851db R09: 1ffffffff3390a3b R10: dffffc0000000000 R11: fffffbfff3390a3c R12: dffffc0000000000 R13: ffff88805aa49d58 R14: ffffffff99c851d8 R15: 1ffff92000000f7c FS: 0000000000000000(0000) GS:ffff888125c1b000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055556abd8588 CR3: 000000003963c000 CR4: 0000000000350ef0 Call Trace: debug_object_activate+0x2e2/0x420 lib/debugobjects.c:836 debug_hrtimer_activate kernel/time/hrtimer.c:445 [inline] debug_activate kernel/time/hrtimer.c:484 [inline] enqueue_hrtimer+0x30/0x3a0 kernel/time/hrtimer.c:1088 __run_hrtimer kernel/time/hrtimer.c:1778 [inline] __hrtimer_run_queues+0x656/0xc60 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:arch_stack_walk+0xfc/0x150 arch/x86/kernel/stacktrace.c:27 Code: 48 8d bd 78 ff ff ff 4c 89 e6 4c 89 fa e8 7c 4f 09 00 83 bd 78 ff ff ff 00 74 38 4c 8d bd 78 ff ff ff 4c 89 ff e8 c4 25 09 00 <48> 85 c0 74 24 48 89 df 48 89 c6 4d 89 f3 2e e8 10 a7 12 0a 84 c0 RSP: 0018:ffffc9000b30f5e8 EFLAGS: 00000246 RAX: ffffffff8218151e RBX: ffffc9000b30f6a0 RCX: 1a6b5d39611b9200 RDX: ffffffff90408101 RSI: ffffffff8be334e0 RDI: ffffffff8218151e RBP: ffffc9000b30f670 R08: ffffc9000b30f647 R09: ffffc9000b30f638 R10: dffffc0000000000 R11: fffff52001661ec9 R12: ffff888025881e00 R13: 0000000000000000 R14: ffffffff81ac3870 R15: ffffc9000b30f5e8 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:243 [inline] __kasan_slab_free+0x5b/0x80 mm/kasan/common.c:275 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2417 [inline] slab_free mm/slub.c:4680 [inline] kfree+0x18e/0x440 mm/slub.c:4879 kvfree_rcu_list+0x9e/0x110 mm/slab_common.c:1553 kfree_rcu_work+0x137/0x170 mm/slab_common.c:1605 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 task:kworker/u8:2 state:R running task stack:22120 pid:36 tgid:36 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+0x1798/0x4cc0 kernel/sched/core.c:6961 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7288 irqentry_exit+0x6f/0x90 kernel/entry/common.c:197 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:rcu_read_lock include/linux/rcupdate.h:842 [inline] RIP: 0010:batadv_iv_ogm_slide_own_bcast_window net/batman-adv/bat_iv_ogm.c:762 [inline] RIP: 0010:batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:834 [inline] RIP: 0010:batadv_iv_ogm_schedule+0x45f/0xf00 net/batman-adv/bat_iv_ogm.c:874 Code: 13 8e 31 f6 31 d2 b9 02 00 00 00 45 31 c0 45 31 c9 48 89 84 24 98 00 00 00 50 e8 cc 77 5b f6 48 83 c4 08 e8 e3 8b 37 00 89 c3 <31> ff 89 c6 e8 c8 cc 7d f6 85 db 74 10 e8 6f 7a 64 f6 84 c0 74 0e RSP: 0018:ffffc90000ac7880 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 3e88d24ead3b3800 RDX: 0000000000000000 RSI: ffffffff8be334e0 RDI: ffffffff8be334a0 RBP: ffffc90000ac79d0 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: ffffed100f939317 R12: ffff88803243d080 R13: ffff88803243d090 R14: dffffc0000000000 R15: ffff8880544a0618 batadv_iv_send_outstanding_bat_ogm_packet+0x6c6/0x7e0 net/batman-adv/bat_iv_ogm.c:1714 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3fc/0x770 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 10502 jiffies! g104985 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:27120 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x165/0x360 kernel/sched/core.c:7058 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3fc/0x770 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: CPU: 1 UID: 0 PID: 18228 Comm: syz-executor Not tainted 6.17.0-rc1-syzkaller-00211-g90d970cade8e #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xd33/0x12d0 kernel/smp.c:877 Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 b6 62 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 61 5e 0b 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 45 5e RSP: 0018:ffffc9000c8df540 EFLAGS: 00000293 RAX: ffffffff81b44d4b RBX: 1ffff110170c8341 RCX: ffff88807ae50000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000c8df6c0 R08: ffffffff8fa38137 R09: 1ffffffff1f47026 R10: dffffc0000000000 R11: fffffbfff1f47027 R12: ffff8880b8641a08 R13: dffffc0000000000 R14: ffff8880b873b1c0 R15: 0000000000000000 FS: 0000555565e8e500(0000) GS:ffff888125d1b000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f69c1fe7000 CR3: 0000000039cc0000 CR4: 0000000000350ef0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1044 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline] flush_tlb_mm_range+0x6b1/0x12d0 arch/x86/mm/tlb.c:1451 dup_mmap+0x15a0/0x1ac0 mm/mmap.c:1873 dup_mm kernel/fork.c:1485 [inline] copy_mm+0x13c/0x4b0 kernel/fork.c:1537 copy_process+0x1706/0x3c00 kernel/fork.c:2175 kernel_clone+0x21e/0x840 kernel/fork.c:2605 __do_sys_clone kernel/fork.c:2748 [inline] __se_sys_clone kernel/fork.c:2732 [inline] __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2732 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6d26d85453 Code: 1f 84 00 00 00 00 00 64 48 8b 04 25 10 00 00 00 45 31 c0 31 d2 31 f6 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 89 c2 85 c0 75 2c 64 48 8b 04 25 10 00 00 RSP: 002b:00007ffe26c44428 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f6d26d85453 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 0000555565e8e7d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 000000000011e012 R15: 00007ffe26c445c0