rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P27576/1:b..l P31152/1:b..l rcu: (detected by 0, t=10502 jiffies, g=151557, q=586 ncpus=2) task:syz.5.7026 state:R running task stack:26376 pid:31152 tgid:31148 ppid:25831 task_flags:0x40044c flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7190 irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:231 [inline] RIP: 0010:unwind_next_frame+0x2af/0x20b0 arch/x86/kernel/unwind_orc.c:510 Code: 48 8b 54 24 30 8b 4c 24 28 8b 74 24 20 44 8b 5c 24 18 89 cf 8b 14 95 b4 a8 dc 91 48 8d 04 7f 48 8d 84 00 d4 b1 1a 91 83 c2 01 <48> 3d b4 a8 dc 91 0f 83 4d 08 00 00 41 89 d0 4f 8d 04 40 4f 8d 84 RSP: 0018:ffffc9000c7f6e20 EFLAGS: 00000202 RAX: ffffffff912e27cc RBX: 0000000000000001 RCX: 0000000000033e54 RDX: 0000000000033e5d RSI: 00000000000a7c45 RDI: 0000000000033e54 RBP: ffffc9000c7f6ed8 R08: 0000000000000000 R09: 000000002accd784 R10: 0000000000000002 R11: 0000000000011142 R12: ffffc9000c7f6ee0 R13: ffffc9000c7f6e90 R14: ffffc9000c7f6ec5 R15: ffffffff82114258 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 save_stack+0x160/0x1f0 mm/page_owner.c:165 __reset_page_owner+0x84/0x1a0 mm/page_owner.c:320 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1406 [inline] free_unref_folios+0xa22/0x1610 mm/page_alloc.c:3000 folios_put_refs+0x4be/0x750 mm/swap.c:1002 free_pages_and_swap_cache+0x245/0x4a0 mm/swap_state.c:355 __tlb_batch_free_encoded_pages+0xf9/0x290 mm/mmu_gather.c:136 tlb_batch_pages_flush mm/mmu_gather.c:149 [inline] tlb_flush_mmu_free mm/mmu_gather.c:397 [inline] tlb_flush_mmu+0xe9/0x5a0 mm/mmu_gather.c:404 zap_pte_range mm/memory.c:1893 [inline] zap_pmd_range mm/memory.c:1946 [inline] zap_pud_range mm/memory.c:1975 [inline] zap_p4d_range mm/memory.c:1996 [inline] unmap_page_range+0x1e64/0x43c0 mm/memory.c:2017 unmap_single_vma+0x153/0x240 mm/memory.c:2059 unmap_vmas+0x218/0x470 mm/memory.c:2101 exit_mmap+0x1b0/0xb60 mm/mmap.c:1277 __mmput+0x12a/0x410 kernel/fork.c:1173 mmput+0x62/0x70 kernel/fork.c:1196 exit_mm kernel/exit.c:581 [inline] do_exit+0x7d7/0x2bd0 kernel/exit.c:959 do_group_exit+0xd3/0x2a0 kernel/exit.c:1112 get_signal+0x2671/0x26d0 kernel/signal.c:3034 arch_do_signal_or_restart+0x8f/0x7e0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline] exit_to_user_mode_loop+0x8c/0x540 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x4ee/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f931ef8f749 RSP: 002b:00007f931fe3b038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: 0000000000010106 RBX: 00007f931f1e6090 RCX: 00007f931ef8f749 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000004 RBP: 00007f931f013f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f931f1e6128 R14: 00007f931f1e6090 R15: 00007fffd64b5c38 task:syz-executor state:R running task stack:22520 pid:27576 tgid:27576 ppid:27569 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 preempt_schedule_notrace+0x62/0xe0 kernel/sched/core.c:7140 preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13 rcu_is_watching+0x8e/0xc0 kernel/rcu/tree.c:752 trace_lock_acquire include/trace/events/lock.h:24 [inline] lock_acquire+0x2cd/0x330 kernel/locking/lockdep.c:5831 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:867 [inline] class_rcu_constructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0xd1/0x20b0 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415 kmalloc_node_noprof include/linux/slab.h:983 [inline] __get_vm_area_node+0x101/0x330 mm/vmalloc.c:3208 __vmalloc_node_range_noprof+0x247/0x16b0 mm/vmalloc.c:4011 __vmalloc_node_noprof+0xad/0xf0 mm/vmalloc.c:4111 alloc_counters net/ipv4/netfilter/ip_tables.c:799 [inline] 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+0x6b6/0xaa0 net/ipv4/netfilter/ip_tables.c:1668 nf_getsockopt+0x7c/0xe0 net/netfilter/nf_sockopt.c:116 ip_getsockopt+0x18c/0x1e0 net/ipv4/ip_sockglue.c:1777 tcp_getsockopt+0xa1/0x100 net/ipv4/tcp.c:4832 do_sock_getsockopt+0x324/0x410 net/socket.c:2383 __sys_getsockopt+0x12f/0x260 net/socket.c:2412 __do_sys_getsockopt net/socket.c:2419 [inline] __se_sys_getsockopt net/socket.c:2416 [inline] __x64_sys_getsockopt+0xbd/0x160 net/socket.c:2416 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f75a219148a RSP: 002b:00007fff0c9e1318 EFLAGS: 00000216 ORIG_RAX: 0000000000000037 RAX: ffffffffffffffda RBX: 00007fff0c9e13a0 RCX: 00007f75a219148a RDX: 0000000000000041 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 0000000000000003 R08: 00007fff0c9e133c R09: 0079746972756365 R10: 00007fff0c9e13a0 R11: 0000000000000216 R12: 00007f75a23b9960 R13: 00007fff0c9e133c R14: 0000000000000000 R15: 00007f75a23ba020 rcu: rcu_preempt kthread starved for 10593 jiffies! g151557 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:28064 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6960 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82 Code: a6 5f 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 13 19 12 00 fb f4 cc 35 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffffff8e007df8 EFLAGS: 000002c6 RAX: 0000000007a95109 RBX: 0000000000000000 RCX: ffffffff8b7846d9 RDX: 0000000000000000 RSI: ffffffff8dacea71 RDI: ffffffff8bf2b400 RBP: fffffbfff1c12f68 R08: 0000000000000001 R09: ffffed101708673d R10: ffff8880b84339eb R11: ffffffff8e098670 R12: 0000000000000000 R13: ffffffff8e097b40 R14: ffffffff9088b9d0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881248f5000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c337c51 CR3: 00000000a3157000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x38d/0x510 kernel/sched/idle.c:332 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430 rest_init+0x16b/0x2b0 init/main.c:757 start_kernel+0x3ef/0x4d0 init/main.c:1206 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x148