rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=6d94/1/0x4000000000000000 softirq=19081/19088 fqs=0 rcu: (detected by 1, t=10502 jiffies, g=12057, q=1465 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 6225 Comm: dhcpcd-run-hook Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x70 kernel/kcov.c:210 Code: 89 fb e8 23 00 00 00 48 8b 3d f4 65 fe 0b 48 89 de 5b e9 23 a1 58 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 8b 04 24 65 48 8b 0c 25 08 b0 a0 92 65 8b 15 18 f1 RSP: 0018:ffffc90000007d00 EFLAGS: 00000097 RAX: ffffffff81adf4ff RBX: ffff888078f70340 RCX: 0000000000010000 RDX: ffff8880273ada00 RSI: 0000000000000000 RDI: 0000000000000007 RBP: 0000000000000000 R08: ffffffff99cb0fa3 R09: 1ffffffff33961f4 R10: dffffc0000000000 R11: fffffbfff33961f5 R12: dffffc0000000000 R13: dffffc0000000000 R14: ffff8880b8627b80 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888125c15000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff2c110a286 CR3: 000000002fc88000 CR4: 00000000003526f0 Call Trace: cpu_max_bits_warn include/linux/cpumask.h:135 [inline] cpumask_check include/linux/cpumask.h:142 [inline] cpumask_test_cpu include/linux/cpumask.h:646 [inline] cpu_online include/linux/cpumask.h:1205 [inline] trace_hrtimer_start include/trace/events/timer.h:222 [inline] debug_activate kernel/time/hrtimer.c:485 [inline] enqueue_hrtimer+0x5e/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+0x108/0x410 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:rcu_preempt_read_enter kernel/rcu/tree_plugin.h:391 [inline] RIP: 0010:__rcu_read_lock+0x1c/0x60 kernel/rcu/tree_plugin.h:414 Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 53 65 48 8b 1c 25 08 b0 a0 92 48 81 c3 44 04 00 00 48 89 d8 48 c1 e8 03 <48> b9 00 00 00 00 00 fc ff df 0f b6 04 08 84 c0 75 18 ff 03 8b 03 RSP: 0018:ffffc90004e3ef08 EFLAGS: 00000a03 RAX: 1ffff11004e75bc8 RBX: ffff8880273ade44 RCX: 141e7c9edf883100 RDX: dffffc0000000000 RSI: ffffffff82186319 RDI: ffffc90004e3efe8 RBP: dffffc0000000000 R08: ffffc90004e3f0b0 R09: 0000000000000006 R10: ffffc90004e3f038 R11: ffffffff81ac4b00 R12: 1ffff920009c7dfd R13: ffffc90004e3f020 R14: ffffc90004e3efe8 R15: ffffc90004e3f690 rcu_read_lock include/linux/rcupdate.h:839 [inline] class_rcu_constructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0x9e/0x2390 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 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 unpoison_slab_object mm/kasan/common.c:330 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:356 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4191 [inline] slab_alloc_node mm/slub.c:4240 [inline] kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4247 kmem_alloc_batch lib/debugobjects.c:371 [inline] fill_pool+0x100/0x570 lib/debugobjects.c:403 debug_objects_fill_pool lib/debugobjects.c:725 [inline] debug_object_activate+0x383/0x420 lib/debugobjects.c:814 debug_rcu_head_queue kernel/rcu/rcu.h:236 [inline] __call_rcu_common kernel/rcu/tree.c:3108 [inline] call_rcu+0xaa/0x9c0 kernel/rcu/tree.c:3243 slab_free_hook mm/slub.c:2386 [inline] slab_free mm/slub.c:4695 [inline] kmem_cache_free+0x309/0x400 mm/slub.c:4797 exit_mmap+0x53f/0xb50 mm/mmap.c:1305 __mmput+0x118/0x430 kernel/fork.c:1129 exec_mmap+0x6ac/0x7d0 fs/exec.c:901 begin_new_exec+0x129c/0x2120 fs/exec.c:1156 load_elf_binary+0x998/0x2740 fs/binfmt_elf.c:995 search_binary_handler fs/exec.c:1670 [inline] exec_binprm fs/exec.c:1702 [inline] bprm_execve+0x99c/0x1450 fs/exec.c:1754 do_execveat_common+0x510/0x6a0 fs/exec.c:1860 do_execve fs/exec.c:1934 [inline] __do_sys_execve fs/exec.c:2010 [inline] __se_sys_execve fs/exec.c:2005 [inline] __x64_sys_execve+0x94/0xb0 fs/exec.c:2005 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: 0033:0x7ff2c1050107 Code: Unable to access opcode bytes at 0x7ff2c10500dd. RSP: 002b:00007ffd2adadbb8 EFLAGS: 00000246 ORIG_RAX: 000000000000003b RAX: ffffffffffffffda RBX: 00005636b8d91fe0 RCX: 00007ff2c1050107 RDX: 00005636b8d92000 RSI: 00005636b8d91fe0 RDI: 00005636b8d92088 RBP: 00005636b8d92088 R08: 00007ffd2adb0eac R09: 0000000000000000 R10: 0000000000000008 R11: 0000000000000246 R12: 00005636b8d92000 R13: 00007ff2c1215e8b R14: 00005636b8d92000 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10502 jiffies! g12057 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:27160 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+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x436/0x7d0 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: 6060 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xd38/0x12d0 kernel/smp.c:877 Code: 89 ee 83 e6 01 31 ff e8 56 63 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 01 5f 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 e5 5e 0b 00 eb e4 44 RSP: 0000:ffffc9000456f720 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 1ffff110170c8341 RCX: ffff888030618000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000456f8a0 R08: ffffffff8fa3a737 R09: 1ffffffff1f474e6 R10: dffffc0000000000 R11: fffffbfff1f474e7 R12: ffff8880b8641a08 R13: dffffc0000000000 R14: ffff8880b873b1c0 R15: 0000000000000000 FS: 00007f112dc8f880(0000) GS:ffff888125d15000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000559b2e99cf28 CR3: 000000007f948000 CR4: 00000000003526f0 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 flush_tlb_page arch/x86/include/asm/tlbflush.h:324 [inline] ptep_clear_flush+0x120/0x170 mm/pgtable-generic.c:101 wp_page_copy mm/memory.c:3618 [inline] do_wp_page+0x1bc2/0x5800 mm/memory.c:4013 handle_pte_fault mm/memory.c:6068 [inline] __handle_mm_fault+0x1033/0x5440 mm/memory.c:6195 handle_mm_fault+0x40a/0x8e0 mm/memory.c:6364 do_user_addr_fault+0xa81/0x1390 arch/x86/mm/fault.c:1336 handle_page_fault arch/x86/mm/fault.c:1476 [inline] exc_page_fault+0x76/0xf0 arch/x86/mm/fault.c:1532 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0033:0x7f112d4b5b69 Code: 10 48 81 f9 ff 03 00 00 76 28 48 8b 57 20 48 85 d2 74 1f 48 3b 7a 28 75 76 48 8b 4f 28 48 3b 79 20 75 6c 48 83 78 20 00 74 17 <48> 89 4a 28 48 89 51 20 48 83 c4 08 c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffd0c275630 EFLAGS: 00010206 RAX: 00007f112d5f2090 RBX: 0000000000000a10 RCX: 0000559b2e99cf00 RDX: 0000559b2e99cf00 RSI: 00007f112d5f2090 RDI: 0000559b2e99cf00 RBP: 00007f112d5f1ac0 R08: 0000000000000a10 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000559b2e998540 R13: 00007f112d5f1ac0 R14: 0000000000000a10 R15: 00007f112d5f1ac0