rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 1, t=10502 jiffies, g=15845, q=4206 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 1722 (4294957130-4294955408), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 1722 jiffies! g15845 f0x2 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:27496 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 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: 5611 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 RIP: 0010:on_stack arch/x86/include/asm/stacktrace.h:56 [inline] RIP: 0010:stack_access_ok arch/x86/kernel/unwind_orc.c:409 [inline] RIP: 0010:deref_stack_reg arch/x86/kernel/unwind_orc.c:419 [inline] RIP: 0010:unwind_next_frame+0xb64/0x2550 arch/x86/kernel/unwind_orc.c:614 Code: 00 74 09 e8 4e 07 bd 00 4c 8b 04 24 4d 8b 7e 08 49 8d 7e 10 49 89 fc 49 c1 ec 03 48 b8 00 00 00 00 00 fc ff df 41 80 3c 04 00 <74> 09 e8 25 07 bd 00 4c 8b 04 24 49 8d 50 f8 4d 8b 6e 10 48 b8 00 RSP: 0018:ffffc90000a08840 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: 1ffff9200014111e RCX: ffffffff90709c60 RDX: ffffffff90ee8abc RSI: 0000000000000002 RDI: ffffc90000a088f8 RBP: 1ffffffff21dd157 R08: ffffc900037c7660 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8eb59c60 R12: 1ffff9200014111f R13: ffffffff90ee8ab8 R14: ffffc90000a088e8 R15: ffffc900037c0000 FS: 0000000000000000(0000) GS:ffff888125054000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fbb593ed2f8 CR3: 000000000e946000 CR4: 00000000003526f0 Call Trace: arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2705 [inline] slab_free mm/slub.c:6405 [inline] kmem_cache_free+0x182/0x650 mm/slub.c:6532 mac80211_hwsim_beacon_tx+0x396/0x820 drivers/net/wireless/virtual/mac80211_hwsim_main.c:2493 __iterate_interfaces+0x2af/0x5a0 net/mac80211/util.c:775 ieee80211_iterate_active_interfaces_atomic+0xdb/0x180 net/mac80211/util.c:811 mac80211_hwsim_beacon+0xaf/0x240 drivers/net/wireless/virtual/mac80211_hwsim_main.c:2525 __run_hrtimer kernel/time/hrtimer.c:2032 [inline] __hrtimer_run_queues+0x3bc/0xa10 kernel/time/hrtimer.c:2096 hrtimer_run_softirq+0x17a/0x240 kernel/time/hrtimer.c:2113 handle_softirqs+0x225/0x840 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0xca/0x220 kernel/softirq.c:735 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0x10b0/0x14b0 kernel/smp.c:892 Code: c0 75 73 41 8b 1e 89 de 83 e6 01 31 ff e8 d8 22 0c 00 83 e3 01 48 bb 00 00 00 00 00 fc ff df 75 07 e8 84 1e 0c 00 eb 37 f3 90 <41> 0f b6 04 1c 84 c0 75 10 41 f7 06 01 00 00 00 74 1e e8 69 1e 0c RSP: 0018:ffffc900037c7460 EFLAGS: 00000293 RAX: ffffffff81bae317 RBX: dffffc0000000000 RCX: ffff888032585d00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc900037c7588 R08: ffffffff90578f37 R09: 1ffffffff20af1e6 R10: dffffc0000000000 R11: fffffbfff20af1e7 R12: 1ffff110170c85fd R13: ffff8880b873c448 R14: ffff8880b8642fe8 R15: 0000000000000000 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1057 __flush_tlb_multi arch/x86/include/asm/paravirt.h:46 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline] flush_tlb_mm_range+0x5c4/0x1090 arch/x86/mm/tlb.c:1451 tlb_flush arch/x86/include/asm/tlb.h:23 [inline] tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:509 [inline] tlb_flush_mmu+0x1af/0xa30 mm/mmu_gather.c:423 tlb_finish_mmu+0xf4/0x220 mm/mmu_gather.c:549 free_ldt_pgtables+0x192/0x360 arch/x86/kernel/ldt.c:411 arch_exit_mmap arch/x86/include/asm/mmu_context.h:229 [inline] exit_mmap+0x1bf/0x9f0 mm/mmap.c:1285 __mmput+0x118/0x420 kernel/fork.c:1187 exit_mm+0x221/0x2d0 kernel/exit.c:615 do_exit+0x6cd/0x2360 kernel/exit.c:997 do_group_exit+0x22d/0x2f0 kernel/exit.c:1152 get_signal+0x121b/0x12c0 kernel/signal.c:3046 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x104/0x730 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb02ef59017 Code: Unable to access opcode bytes at 0x7fb02ef58fed. RSP: 002b:00007ffc792285c0 EFLAGS: 00000202 ORIG_RAX: 000000000000003d RAX: fffffffffffffe00 RBX: 000055555fa8e500 RCX: 00007fb02ef59017 RDX: 0000000040000000 RSI: 00007ffc7922861c RDI: ffffffffffffffff RBP: 00007ffc7922861c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000008 R13: 0000000000000003 R14: 00007ffc79228878 R15: 0000000000000000