rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5831/1:b..l P1100/1:b..l P5761/1:b..l P5136/1:b..l rcu: (detected by 1, t=10502 jiffies, g=9617, q=888 ncpus=2) task:udevd state:R running task stack:25160 pid:5136 ppid:1 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6866 preempt_schedule+0xab/0xc0 kernel/sched/core.c:6890 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3a/0x40 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] fast_dput+0x11e/0x280 fs/dcache.c:-1 dput+0xdd/0x1e0 fs/dcache.c:905 step_into+0x343/0xf10 fs/namei.c:1863 walk_component fs/namei.c:2016 [inline] link_path_walk+0x6df/0xe00 fs/namei.c:2337 path_openat+0x283/0x3190 fs/namei.c:3793 do_filp_open+0x1c5/0x3d0 fs/namei.c:3824 do_sys_openat2+0x12c/0x1c0 fs/open.c:1421 do_sys_open fs/open.c:1436 [inline] __do_sys_openat fs/open.c:1452 [inline] __se_sys_openat fs/open.c:1447 [inline] __x64_sys_openat+0x139/0x160 fs/open.c:1447 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f6484f15c3a RSP: 002b:00007fff634cc828 EFLAGS: 00000206 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 000056516eea94b0 RCX: 00007f6484f15c3a RDX: 0000000000090800 RSI: 000056516ee82790 RDI: 00000000ffffff9c RBP: 000056516ee82790 R08: 0000000000000000 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000206 R12: 000056516ee8e7b0 R13: 00000000000000ff R14: 000056514d901be0 R15: 00007fff634ccab0 task:syz-executor state:R running task stack:21384 pid:5761 ppid:5758 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6866 preempt_schedule+0xab/0xc0 kernel/sched/core.c:6890 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3a/0x40 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] copy_pte_range mm/memory.c:1107 [inline] copy_pmd_range mm/memory.c:1168 [inline] copy_pud_range mm/memory.c:1205 [inline] copy_p4d_range mm/memory.c:1229 [inline] copy_page_range+0x2b7c/0x3600 mm/memory.c:1323 dup_mmap kernel/fork.c:764 [inline] dup_mm kernel/fork.c:1692 [inline] copy_mm+0x11a8/0x1ca0 kernel/fork.c:1741 copy_process+0x16d3/0x3d70 kernel/fork.c:2506 kernel_clone+0x21b/0x840 kernel/fork.c:2914 __do_sys_clone kernel/fork.c:3057 [inline] __se_sys_clone kernel/fork.c:3041 [inline] __x64_sys_clone+0x18c/0x1e0 kernel/fork.c:3041 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fdfe8b85e93 RSP: 002b:00007ffe80e0de78 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fdfe8b85e93 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 000055557fa367d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 00000000000145b5 R15: 00007ffe80e0e010 task:kworker/u4:8 state:R running task stack:23944 pid:1100 ppid:2 flags:0x00004000 Workqueue: bat_events batadv_nc_worker Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009 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+0x1f2/0x410 kernel/locking/lockdep.c:5758 Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f5 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 66 43 c7 44 3c 09 00 00 43 c6 44 3c 0b 00 RSP: 0018:ffffc900046ffa40 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 142614b878571000 RDX: 0000000000000000 RSI: ffffffff8aaace60 RDI: ffffffff8afc6f80 RBP: ffffc900046ffb48 R08: dffffc0000000000 R09: 1ffffffff21b28a0 R10: dffffc0000000000 R11: fffffbfff21b28a1 R12: 1ffff920008dff54 R13: ffffffff8cd2ff20 R14: 0000000000000246 R15: dffffc0000000000 rcu_lock_acquire include/linux/rcupdate.h:334 [inline] rcu_read_lock include/linux/rcupdate.h:786 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline] batadv_nc_worker+0xef/0x610 net/batman-adv/network-coding.c:719 process_one_work kernel/workqueue.c:2634 [inline] process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792 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:kworker/0:4 state:R running task stack:23224 pid:5831 ppid:2 flags:0x00004000 Workqueue: events_power_efficient gc_worker Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009 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:seqcount_lockdep_reader_access+0x17f/0x1c0 include/linux/seqlock.h:105 Code: f8 4d 85 e4 75 16 e8 80 c1 e0 f8 eb 15 e8 79 c1 e0 f8 e8 04 a8 c2 01 4d 85 e4 74 ea e8 6a c1 e0 f8 fb 48 c7 04 24 0e 36 e0 45 <4b> c7 04 3e 00 00 00 00 66 43 c7 44 3e 09 00 00 43 c6 44 3e 0b 00 RSP: 0018:ffffc9000491f9a0 EFLAGS: 00000293 RAX: ffffffff88a4cf56 RBX: 0000000000000000 RCX: ffff88802c3f3c00 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc9000491fa50 R08: ffffffff90d94597 R09: 1ffffffff21b28b2 R10: dffffc0000000000 R11: fffffbfff21b28b3 R12: 0000000000000200 R13: dffffc0000000000 R14: 1ffff92000923f34 R15: dffffc0000000000 nf_conntrack_get_ht include/net/netfilter/nf_conntrack.h:350 [inline] gc_worker+0x317/0x14b0 net/netfilter/nf_conntrack_core.c:1504 process_one_work kernel/workqueue.c:2634 [inline] process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792 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: rcu_preempt kthread starved for 10607 jiffies! g9617 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:27160 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 schedule+0xbd/0x170 kernel/sched/core.c:6773 schedule_timeout+0x160/0x280 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x99/0x380 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 5877 Comm: syz.2.7 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:unwind_done arch/x86/include/asm/unwind.h:50 [inline] RIP: 0010:unwind_next_frame+0x98/0x2970 arch/x86/kernel/unwind_orc.c:475 Code: 5a a2 00 49 8b 44 24 38 48 89 84 24 90 00 00 00 4c 89 e3 48 c1 eb 03 42 0f b6 04 2b 84 c0 0f 85 df 21 00 00 41 8b 2c 24 31 ff <89> ee e8 91 f0 4a 00 89 ac 24 8c 00 00 00 85 ed 74 77 4c 89 74 24 RSP: 0018:ffffc90000007878 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 1ffff92000000f29 RCX: ffff888021180000 RDX: 0000000000010000 RSI: ffffffff8153bdfc RDI: 0000000000000000 RBP: 0000000000000002 R08: ffffc90000007a10 R09: 0000000000000004 R10: 0000000000000004 R11: 0000000000010000 R12: ffffc90000007948 R13: dffffc0000000000 R14: ffffc90000007980 R15: ffffffff8153bdfc FS: 00007fcc6e1956c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fdfe99156c0 CR3: 000000001ebfb000 CR4: 00000000003506f0 Call Trace: arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:52 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:328 kasan_slab_alloc include/linux/kasan.h:188 [inline] slab_post_alloc_hook+0x6e/0x4d0 mm/slab.h:767 slab_alloc_node mm/slub.c:3495 [inline] slab_alloc mm/slub.c:3503 [inline] __kmem_cache_alloc_lru mm/slub.c:3510 [inline] kmem_cache_alloc+0x11e/0x2e0 mm/slub.c:3519 __sigqueue_alloc+0x40c/0x520 kernel/signal.c:438 __send_signal_locked+0x22f/0xe00 kernel/signal.c:1130 do_send_sig_info kernel/signal.c:1312 [inline] group_send_sig_info+0x1fa/0x260 kernel/signal.c:1462 do_bpf_send_signal+0x7f/0x190 kernel/trace/bpf_trace.c:836 irq_work_single+0xd5/0x230 kernel/irq_work.c:221 irq_work_run_list kernel/irq_work.c:252 [inline] irq_work_run+0x156/0x2e0 kernel/irq_work.c:261 __sysvec_irq_work+0x98/0x380 arch/x86/kernel/irq_work.c:22 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline] sysvec_irq_work+0x9c/0xc0 arch/x86/kernel/irq_work.c:17 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:723 RIP: 0010:arch_static_branch arch/x86/include/asm/jump_label.h:27 [inline] RIP: 0010:static_key_false include/linux/jump_label.h:207 [inline] RIP: 0010:native_write_msr arch/x86/include/asm/msr.h:147 [inline] RIP: 0010:wrmsr arch/x86/include/asm/msr.h:254 [inline] RIP: 0010:native_apic_msr_write+0x39/0x50 arch/x86/include/asm/apic.h:196 Code: 74 2a 83 ff 30 74 25 eb 10 81 ff d0 00 00 00 74 1b 81 ff e0 00 00 00 74 13 c1 ef 04 81 c7 00 08 00 00 89 f9 89 f0 31 d2 0f 30 <66> 90 c3 f3 0f 1e fa 89 f6 31 d2 e9 f7 36 19 03 0f 1f 80 00 00 00 RSP: 0018:ffffc90004a3fcd8 EFLAGS: 00000246 RAX: 00000000000000f6 RBX: 0000000000000200 RCX: 000000000000083f RDX: 0000000000000000 RSI: 00000000000000f6 RDI: 000000000000083f RBP: 0000000000000000 R08: ffffc90004a3fc47 R09: 1ffff92000947f88 R10: dffffc0000000000 R11: fffff52000947f89 R12: ffff8880b8e35001 R13: dffffc0000000000 R14: ffff8880b8e35050 R15: 0000000000000020 __apic_send_IPI_self arch/x86/include/asm/apic.h:454 [inline] arch_irq_work_raise+0x68/0x70 arch/x86/kernel/irq_work.c:31 irq_work_queue+0x99/0x140 kernel/irq_work.c:124 bpf_send_signal_common+0x2b6/0x420 kernel/trace/bpf_trace.c:875 ____bpf_send_signal kernel/trace/bpf_trace.c:884 [inline] bpf_send_signal+0x19/0x20 kernel/trace/bpf_trace.c:882 bpf_prog_7ba5217f62dcd359+0x40/0x44 bpf_dispatcher_nop_func include/linux/bpf.h:1224 [inline] __bpf_prog_run include/linux/filter.h:612 [inline] bpf_prog_run include/linux/filter.h:619 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline] bpf_trace_run2+0x1d1/0x3c0 kernel/trace/bpf_trace.c:2361 trace_sys_enter+0x69/0x80 include/trace/events/syscalls.h:18 syscall_trace_enter+0xf0/0x150 kernel/entry/common.c:81 do_syscall_64+0x28/0xb0 arch/x86/entry/common.c:77 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fcc6d32b829 Code: 64 c7 00 16 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 0f 05 <0f> 1f 80 00 00 00 00 48 81 ec 48 01 00 00 49 89 d0 64 48 8b 04 25 RSP: 002b:00007fcc6e194b40 EFLAGS: 00000246 ORIG_RAX: 000000000000000f RAX: ffffffffffffffda RBX: 00007fcc6d5e6098 RCX: 00007fcc6d32b829 RDX: 00007fcc6e194b40 RSI: 00007fcc6e194c70 RDI: 0000000000000011 RBP: 00007fcc6d5e6090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fcc6d5e6128 R14: 00007fff361b1070 R15: 00007fff361b1158 sched: RT throttling activated