rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=ac44/1/0x4000000000000000 softirq=19516/19517 fqs=1 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5962/1:b..l rcu: (detected by 1, t=10504 jiffies, g=13993, q=505 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5194 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:check_preemption_disabled+0x40/0x120 lib/smp_processor_id.c:53 Code: 08 65 8b 05 b6 74 49 07 65 8b 0d ab 74 49 07 f7 c1 ff ff ff 7f 74 23 65 48 8b 0d 8b 74 49 07 48 3b 4c 24 08 0f 85 cc 00 00 00 <48> 83 c4 10 5b 41 5e 41 5f 5d c3 cc cc cc cc cc 48 c7 04 24 00 00 RSP: 0018:ffffc90000007cb0 EFLAGS: 00000046 RAX: 0000000000000000 RBX: ffff8880217cd340 RCX: 80d8d757fc46db00 RDX: ffff88807beb8000 RSI: ffffffff8bc03b40 RDI: ffffffff8bc03b00 RBP: 0000000000000001 R08: ffffffff8f9d4c37 R09: 1ffffffff1f3a986 R10: dffffc0000000000 R11: fffffbfff1f3a987 R12: dffffc0000000000 R13: 0000000000000000 R14: ffff8880b8627bc0 R15: 0000000000000000 FS: 00007f2949213880(0000) GS:ffff888125d3b000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fadba9b12f8 CR3: 000000007c354000 CR4: 00000000003526f0 Call Trace: rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline] rcu_is_watching+0x15/0xb0 kernel/rcu/tree.c:751 trace_hrtimer_start include/trace/events/timer.h:222 [inline] debug_activate kernel/time/hrtimer.c:478 [inline] enqueue_hrtimer+0x9d/0x3a0 kernel/time/hrtimer.c:1081 __run_hrtimer kernel/time/hrtimer.c:1794 [inline] __hrtimer_run_queues+0x656/0xc60 kernel/time/hrtimer.c:1841 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline] __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1058 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1052 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:seqcount_lockdep_reader_access+0x17d/0x1c0 include/linux/seqlock.h:75 Code: ff 4d 85 ed 75 16 e8 02 0b 86 ff eb 15 e8 fb 0a 86 ff e8 c6 b1 0b 09 4d 85 ed 74 ea e8 ec 0a 86 ff fb 48 c7 04 24 0e 36 e0 45 <4b> c7 04 27 00 00 00 00 66 43 c7 44 27 09 00 00 43 c6 44 27 0b 00 RSP: 0018:ffffc900031377a0 EFLAGS: 00000293 RAX: ffffffff82391084 RBX: 0000000000000000 RCX: ffff88807beb8000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90003137860 R08: ffffffff8f9d4c37 R09: 1ffffffff1f3a986 R10: dffffc0000000000 R11: fffffbfff1f3a987 R12: dffffc0000000000 R13: 0000000000000200 R14: ffffffff82391681 R15: 1ffff92000626ef4 read_seqbegin include/linux/seqlock.h:836 [inline] set_root+0x161/0x3b0 fs/namei.c:1015 nd_jump_root+0x2b4/0x430 fs/namei.c:1036 path_init+0x373/0x1350 fs/namei.c:2583 path_lookupat+0x27/0x430 fs/namei.c:2666 filename_lookup+0x212/0x570 fs/namei.c:2705 vfs_statx+0xf8/0x550 fs/stat.c:353 vfs_fstatat+0x118/0x170 fs/stat.c:375 __do_sys_newfstatat fs/stat.c:542 [inline] __se_sys_newfstatat fs/stat.c:536 [inline] __x64_sys_newfstatat+0x116/0x190 fs/stat.c:536 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2948b11b0a Code: 48 8b 15 f1 f2 0d 00 f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 41 89 ca b8 06 01 00 00 0f 05 <3d> 00 f0 ff ff 77 07 31 c0 c3 0f 1f 40 00 48 8b 15 b9 f2 0d 00 f7 RSP: 002b:00007ffd742a25a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000106 RAX: ffffffffffffffda RBX: 000055c6010ad410 RCX: 00007f2948b11b0a RDX: 00007ffd742a25b0 RSI: 000055c60109b2a8 RDI: 00000000ffffff9c RBP: 000055c627b92148 R08: 00063478c1c69200 R09: 3fffffffffffffff R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffd742a25b0 R14: 0000000000000000 R15: 00063478c1c69200 task:syz-executor state:R running task stack:21768 pid:5962 tgid:5962 ppid:5954 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707 RIP: 0010:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5872 Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 6b ec f1 10 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc90003046e78 EFLAGS: 00000206 RAX: 3bb31842ff8c5b00 RBX: 0000000000000000 RCX: 3bb31842ff8c5b00 RDX: 0000000000000000 RSI: ffffffff8d9c68ab RDI: ffffffff8bc03b60 RBP: ffffffff8172ad05 R08: 0000000000000000 R09: ffffffff8172ad05 R10: ffffc90003047038 R11: ffffffff81ab4450 R12: 0000000000000002 R13: ffffffff8e13a960 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] class_rcu_constructor include/linux/rcupdate.h:1169 [inline] unwind_next_frame+0xc2/0x2390 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_node_noprof+0x1bb/0x3c0 mm/slub.c:4292 alloc_vmap_area+0x271/0x14a0 mm/vmalloc.c:2043 __get_vm_area_node+0x1f8/0x300 mm/vmalloc.c:3187 __vmalloc_node_range_noprof+0x301/0x12f0 mm/vmalloc.c:3853 __vmalloc_node_noprof mm/vmalloc.c:3956 [inline] vzalloc_noprof+0xb2/0xf0 mm/vmalloc.c:4030 alloc_counters+0xd3/0x6d0 net/ipv4/netfilter/ip_tables.c:799 copy_entries_to_user net/ipv4/netfilter/ip_tables.c:821 [inline] get_entries net/ipv4/netfilter/ip_tables.c:1022 [inline] do_ipt_get_ctl+0xaac/0x1180 net/ipv4/netfilter/ip_tables.c:1668 nf_getsockopt+0x26b/0x290 net/netfilter/nf_sockopt.c:116 ip_getsockopt+0x1c4/0x220 net/ipv4/ip_sockglue.c:1777 do_sock_getsockopt+0x372/0x450 net/socket.c:2421 __sys_getsockopt net/socket.c:2450 [inline] __do_sys_getsockopt net/socket.c:2457 [inline] __se_sys_getsockopt net/socket.c:2454 [inline] __x64_sys_getsockopt+0x1a5/0x250 net/socket.c:2454 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fadba790c0a RSP: 002b:00007fffc4416768 EFLAGS: 00000202 ORIG_RAX: 0000000000000037 RAX: ffffffffffffffda RBX: 00007fffc44167f0 RCX: 00007fadba790c0a RDX: 0000000000000041 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 0000000000000003 R08: 00007fffc441678c R09: 00007fffc4416ba7 R10: 00007fffc44167f0 R11: 0000000000000202 R12: 00007fadba9b62a0 R13: 00007fffc441678c R14: 0000000000000000 R15: 00007fadba9b7020 rcu: rcu_preempt kthread timer wakeup didn't happen for 10498 jiffies! g13993 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=6851 rcu: rcu_preempt kthread starved for 10499 jiffies! g13993 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27080 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0x165/0x360 kernel/sched/core.c:7026 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+0x4b9/0x870 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245