rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5972 rcu: (detected by 1, t=10503 jiffies, g=11225, q=1081 ncpus=2) task:syz.1.19 state:R running task stack:25736 pid:5972 ppid:5827 flags:0x0000400a Call Trace: sched_show_task+0x481/0x5a0 kernel/sched/core.c:9179 rcu_print_detail_task_stall_rnp kernel/rcu/tree_stall.h:261 [inline] print_other_cpu_stall+0xfa7/0x1340 kernel/rcu/tree_stall.h:637 check_cpu_stall kernel/rcu/tree_stall.h:809 [inline] rcu_pending kernel/rcu/tree.c:3950 [inline] rcu_sched_clock_irq+0x87c/0x1220 kernel/rcu/tree.c:2295 update_process_times+0x147/0x1b0 kernel/time/timer.c:2071 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x3a2/0x580 kernel/time/tick-sched.c:1492 __run_hrtimer kernel/time/hrtimer.c:1755 [inline] __hrtimer_run_queues+0x4df/0xc40 kernel/time/hrtimer.c:1819 hrtimer_interrupt+0x3c9/0x9c0 kernel/time/hrtimer.c:1881 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline] __sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline] sysvec_apic_timer_interrupt+0x51/0xc0 arch/x86/kernel/apic/apic.c:1088 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:212 Code: 00 0f 0b 0f 1f 80 00 00 00 00 f3 0f 1e fa 53 48 89 fb e8 13 00 00 00 48 8b 3d ec e8 c4 0c 48 89 de 5b e9 f3 74 56 00 cc cc cc 0f 1e fa 48 8b 04 24 65 48 8b 0d c0 23 7e 7e 65 8b 15 c1 23 7e RSP: 0018:ffffc900001f0468 EFLAGS: 00000246 RAX: 0000000000000020 RBX: 0000000000000004 RCX: 0000000000000005 RDX: ffffffff818760c5 RSI: ffffffff8cd79100 RDI: 0000000000000004 RBP: 00000000000008fc R08: ffff888078fb5a00 R09: 0000000000000020 R10: 000000000000001f R11: 0000000000000100 R12: dffffc0000000000 R13: f800000000000000 R14: ffff88801c6635d8 R15: 00000000000c31a4 rb_event_length+0x148/0x3f0 kernel/trace/ring_buffer.c:198 check_buffer+0x542/0x950 kernel/trace/ring_buffer.c:3491 __rb_reserve_next+0x511/0xd50 kernel/trace/ring_buffer.c:3624 rb_reserve_next_event kernel/trace/ring_buffer.c:3759 [inline] ring_buffer_lock_reserve+0xae1/0xed0 kernel/trace/ring_buffer.c:3818 __trace_buffer_lock_reserve kernel/trace/trace.c:992 [inline] trace_event_buffer_lock_reserve+0x1d0/0x6e0 kernel/trace/trace.c:2902 trace_event_buffer_reserve+0x29b/0x3c0 kernel/trace/trace_events.c:661 do_trace_event_raw_event_bpf_trace_printk kernel/trace/bpf_trace.h:11 [inline] trace_event_raw_event_bpf_trace_printk+0x101/0x210 kernel/trace/bpf_trace.h:11 trace_bpf_trace_printk+0x142/0x1a0 kernel/trace/bpf_trace.h:11 ____bpf_trace_printk kernel/trace/bpf_trace.c:388 [inline] bpf_trace_printk+0x11f/0x190 kernel/trace/bpf_trace.c:371 bpf_prog_0605f9f479290f07+0x37/0x3b bpf_dispatcher_nop_func include/linux/bpf.h:1213 [inline] __bpf_prog_run include/linux/filter.h:605 [inline] bpf_prog_run include/linux/filter.h:619 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline] bpf_trace_run1+0x30a/0x3b0 kernel/trace/bpf_trace.c:2360 __bpf_trace_rcu_utilization+0xa2/0xe0 include/trace/events/rcu.h:27 trace_rcu_utilization+0x179/0x1a0 include/trace/events/rcu.h:27 rcu_core+0x1341/0x1720 kernel/rcu/tree.c:2475 handle_softirqs+0x280/0x820 kernel/softirq.c:578 __do_softirq kernel/softirq.c:612 [inline] invoke_softirq kernel/softirq.c:452 [inline] __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline] sysvec_irq_work+0xa1/0xc0 arch/x86/kernel/irq_work.c:17 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:723 RIP: 0010:rcu_read_unlock_special+0x88/0x4c0 kernel/rcu/tree_plugin.h:682 Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 19 4e 93 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b RSP: 0018:ffffc90004ea7c00 EFLAGS: 00000206 RAX: d3849a87c1b1f100 RBX: 1ffff920009d4f88 RCX: d3849a87c1b1f100 RDX: dffffc0000000000 RSI: ffffffff8aaaba40 RDI: ffffffff8afc6680 RBP: ffffc90004ea7cf0 R08: ffffffff90da2537 R09: 1ffffffff21b44a6 R10: dffffc0000000000 R11: fffffbfff21b44a7 R12: 0000000000000000 R13: dffffc0000000000 R14: 0000000000000246 R15: ffffffff8cd354d8 __rcu_read_unlock+0x7c/0xd0 kernel/rcu/tree_plugin.h:426 rcu_read_unlock+0x85/0xa0 include/linux/rcupdate.h:818 dput+0xe6/0x1e0 fs/dcache.c:911 __fput+0x5e5/0x970 fs/file_table.c:392 task_work_run+0x1ce/0x250 kernel/task_work.c:239 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7feb9038e9a9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fff598ad388 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00000000000541f0 RCX: 00007feb9038e9a9 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007feb905b7ba0 R08: 0000000000000001 R09: 0000000f598ad67f R10: 00007feb90000000 R11: 0000000000000246 R12: 00007feb905b5fac R13: 00007feb905b5fa0 R14: ffffffffffffffff R15: 00007fff598ad4a0 rcu: rcu_preempt kthread starved for 10429 jiffies! g11225 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:27496 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x14e2/0x4580 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 schedule_timeout+0x160/0x280 kernel/time/timer.c:2167 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: 5976 Comm: syz.0.21 Not tainted 6.6.99-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:102 [inline] RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:227 [inline] RIP: 0010:unwind_next_frame+0x4cb/0x2970 arch/x86/kernel/unwind_orc.c:494 Code: 04 10 84 c0 75 3e 4d 63 2f 4d 01 fd 4c 89 ef 4c 89 f6 e8 c8 f0 4a 00 49 8d 47 04 4d 39 f5 4c 0f 46 e0 49 8d 47 fc 48 0f 47 d8 <49> 0f 46 ef 49 39 dc 77 28 e8 97 ee 4a 00 48 ba 00 00 00 00 00 fc RSP: 0018:ffffc90000007598 EFLAGS: 00000216 RAX: ffffffff8e624b3c RBX: ffffffff8e624b3c RCX: ffff888026911e00 RDX: 0000000000000100 RSI: ffffffff81dc8a7f RDI: ffffffff81dc8ae8 RBP: ffffffff8e624b3c R08: ffffc90000007730 R09: 0000000000000003 R10: 0000000000000004 R11: 0000000000000100 R12: ffffffff8e624b3c R13: ffffffff81dc8ae8 R14: ffffffff81dc8a7f R15: ffffffff8e624b40 FS: 000055556aca0500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b30111ff8 CR3: 000000002e367000 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_save_free_info+0x2e/0x50 mm/kasan/generic.c:522 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:236 kasan_slab_free include/linux/kasan.h:164 [inline] slab_free_hook mm/slub.c:1806 [inline] slab_free_freelist_hook+0x130/0x1b0 mm/slub.c:1832 slab_free mm/slub.c:3816 [inline] kmem_cache_free+0xf8/0x280 mm/slub.c:3838 skb_kfree_head net/core/skbuff.c:943 [inline] skb_free_head net/core/skbuff.c:957 [inline] skb_release_data+0x60a/0x800 net/core/skbuff.c:987 skb_release_all net/core/skbuff.c:1053 [inline] __kfree_skb net/core/skbuff.c:1067 [inline] consume_skb+0xb2/0x110 net/core/skbuff.c:1283 mac80211_hwsim_beacon_tx+0x3e9/0x780 drivers/net/wireless/virtual/mac80211_hwsim.c:2269 __iterate_interfaces+0x243/0x500 net/mac80211/util.c:766 ieee80211_iterate_active_interfaces_atomic+0xdb/0x180 net/mac80211/util.c:802 mac80211_hwsim_beacon+0xbb/0x1b0 drivers/net/wireless/virtual/mac80211_hwsim.c:2295 __run_hrtimer kernel/time/hrtimer.c:1755 [inline] __hrtimer_run_queues+0x51e/0xc40 kernel/time/hrtimer.c:1819 hrtimer_run_softirq+0x187/0x2b0 kernel/time/hrtimer.c:1836 handle_softirqs+0x280/0x820 kernel/softirq.c:578 __do_softirq kernel/softirq.c:612 [inline] invoke_softirq kernel/softirq.c:452 [inline] __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline] sysvec_irq_work+0xa1/0xc0 arch/x86/kernel/irq_work.c:17 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:723 RIP: 0010:rcu_read_unlock_special+0x88/0x4c0 kernel/rcu/tree_plugin.h:682 Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 19 4e 93 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b RSP: 0018:ffffc90004eb7c00 EFLAGS: 00000206 RAX: 7cd19f3c4ca8f100 RBX: 1ffff920009d6f88 RCX: 7cd19f3c4ca8f100 RDX: dffffc0000000000 RSI: ffffffff8aaaba40 RDI: ffffffff8afc6680 RBP: ffffc90004eb7cf0 R08: ffffffff90da2537 R09: 1ffffffff21b44a6 R10: dffffc0000000000 R11: fffffbfff21b44a7 R12: 0000000000000000 R13: dffffc0000000000 R14: 0000000000000246 R15: ffffffff8cd354d8 __rcu_read_unlock+0x7c/0xd0 kernel/rcu/tree_plugin.h:426 rcu_read_unlock+0x85/0xa0 include/linux/rcupdate.h:818 dput+0xe6/0x1e0 fs/dcache.c:911 __fput+0x5e5/0x970 fs/file_table.c:392 task_work_run+0x1ce/0x250 kernel/task_work.c:239 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f636b58e9a9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fffd4339c68 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007f636b7b7ba0 RCX: 00007f636b58e9a9 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007f636b7b7ba0 R08: 000000000000da1c R09: 00000016d4339f5f R10: 00007f636b7b7ac0 R11: 0000000000000246 R12: 0000000000054809 R13: 00007f636b7b6160 R14: ffffffffffffffff R15: 00007fffd4339d80