rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5823/1:b..l P6218/1:b..l P6207/1:b..l P5961/1:b..l P5975/1:b..l rcu: (detected by 1, t=10504 jiffies, g=12797, q=988 ncpus=2) task:kworker/u8:12 state:R running task stack:23000 pid:5975 tgid:5975 ppid:2 task_flags:0x4288060 flags:0x00080000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7193 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:kasan_check_range+0x1d4/0x2c0 mm/kasan/generic.c:200 Code: 01 f3 49 8d 5c 24 07 4d 85 e4 49 0f 49 dc 48 83 e3 f8 49 29 dc 74 12 41 80 3b 00 0f 85 b8 00 00 00 49 ff c3 49 ff cc 75 ee 5b <41> 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 45 84 ff 75 63 41 f7 RSP: 0018:ffffc90004c7eea8 EFLAGS: 00000256 RAX: ffffc90004c7f801 RBX: 0000000000000010 RCX: ffffffff81743d8e RDX: 0000000000000001 RSI: 0000000000000010 RDI: ffffc90004c7f018 RBP: 0000000000000000 R08: ffffc90004c7f027 R09: 1ffff9200098fe04 R10: dffffc0000000000 R11: fffff5200098fe05 R12: 0000000000000002 R13: 1ffff9200098fdfb R14: fffff5200098fe05 R15: 1ffff9200098fe03 __asan_memset+0x22/0x50 mm/kasan/shadow.c:84 unwind_next_frame+0xeae/0x23d0 arch/x86/kernel/unwind_orc.c:607 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556 __call_rcu_common kernel/rcu/tree.c:3119 [inline] call_rcu+0x157/0x9c0 kernel/rcu/tree.c:3239 kernfs_put+0x18e/0x470 fs/kernfs/dir.c:591 kernfs_remove_by_name_ns+0xb7/0x130 fs/kernfs/dir.c:1721 kernfs_remove_by_name include/linux/kernfs.h:633 [inline] remove_files fs/sysfs/group.c:28 [inline] sysfs_remove_group+0xfc/0x2f0 fs/sysfs/group.c:328 sysfs_remove_groups+0x54/0xb0 fs/sysfs/group.c:352 device_remove_groups drivers/base/core.c:2843 [inline] device_remove_attrs+0x208/0x260 drivers/base/core.c:2979 device_del+0x509/0x8e0 drivers/base/core.c:3877 unregister_netdevice_many_notify+0x1ddd/0x2340 net/core/dev.c:12435 ops_exit_rtnl_list net/core/net_namespace.c:187 [inline] ops_undo_list+0x3dc/0x990 net/core/net_namespace.c:248 cleanup_net+0x4d8/0x7a0 net/core/net_namespace.c:696 process_one_work+0x93a/0x15a0 kernel/workqueue.c:3279 process_scheduled_works kernel/workqueue.c:3362 [inline] worker_thread+0x9b0/0xee0 kernel/workqueue.c:3443 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 task:udevd state:R running task stack:24048 pid:5961 tgid:5961 ppid:5196 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7193 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_is_held_type+0x137/0x190 kernel/locking/lockdep.c:5945 Code: 01 75 44 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 75 4c 41 f7 c4 00 02 00 00 74 01 fb 65 48 8b 05 49 fa 41 07 <48> 3b 44 24 08 75 43 89 d8 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f RSP: 0018:ffffc90004c1f358 EFLAGS: 00000206 RAX: 3f443b3b591e5600 RBX: 0000000000000001 RCX: 3f443b3b591e5600 RDX: 0000000000000000 RSI: ffffffff8db7ed49 RDI: ffffffff8be07960 RBP: 00000000ffffffff R08: ffffffff8233ecda R09: ffffffff8e13f2e0 R10: dffffc0000000000 R11: ffffed1006327e36 R12: 0000000000000246 R13: ffff88802a103d00 R14: ffffffff8e13f2e0 R15: 0000000000000002 lookup_page_ext mm/page_ext.c:254 [inline] page_ext_lookup+0xe7/0x180 mm/page_ext.c:509 page_ext_iter_begin include/linux/page_ext.h:132 [inline] __page_table_check_zero+0x135/0x3e0 mm/page_table_check.c:139 page_table_check_alloc include/linux/page_table_check.h:35 [inline] post_alloc_hook+0x247/0x290 mm/page_alloc.c:1858 prep_new_page mm/page_alloc.c:1865 [inline] get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3915 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486 folio_alloc_mpol_noprof+0x39/0x70 mm/mempolicy.c:2505 shmem_alloc_folio mm/shmem.c:1902 [inline] shmem_alloc_and_add_folio+0x423/0xf40 mm/shmem.c:1944 shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2568 shmem_get_folio mm/shmem.c:2674 [inline] shmem_write_begin+0x16c/0x330 mm/shmem.c:3327 generic_perform_write+0x2c5/0x900 mm/filemap.c:4314 shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3502 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x5c9/0xb30 fs/read_write.c:686 ksys_write+0x145/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f99e54a7407 RSP: 002b:00007ffca9478cb0 EFLAGS: 00000202 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f99e5bb4880 RCX: 00007f99e54a7407 RDX: 0000000000000020 RSI: 00005593b3a1fa00 RDI: 0000000000000009 RBP: 00005593b3a1fa00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000020 R13: 00005593b3a1d7a0 R14: 00007f99e55efea0 R15: 000055938b7f89dd task:syz.3.80 state:R running task stack:26648 pid:6207 tgid:6206 ppid:5835 task_flags:0x40044c flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7050 preempt_schedule+0xae/0xc0 kernel/sched/core.c:7074 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] zap_pte_range mm/memory.c:1884 [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+0x3c17/0x44e0 mm/memory.c:2017 unmap_single_vma mm/memory.c:2059 [inline] unmap_vmas+0x399/0x580 mm/memory.c:2101 exit_mmap+0x239/0xb10 mm/mmap.c:1277 __mmput+0x118/0x430 kernel/fork.c:1177 exit_mm+0x1da/0x2c0 kernel/exit.c:581 do_exit+0x850/0x25b0 kernel/exit.c:959 do_group_exit+0x21c/0x2d0 kernel/exit.c:1112 get_signal+0x1285/0x1340 kernel/signal.c:3034 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline] exit_to_user_mode_loop+0x87/0x4f0 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+0x2d0/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f7f66f8f749 RSP: 002b:00007f7f67d9e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: 0000000000000004 RBX: 00007f7f671e5fa0 RCX: 00007f7f66f8f749 RDX: 0000000000000000 RSI: 000000000000ae01 RDI: 0000000000000003 RBP: 00007f7f67013f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f7f671e6038 R14: 00007f7f671e5fa0 R15: 00007ffe95b1bf58 task:modprobe state:R running task stack:24312 pid:6218 tgid:6218 ppid:5971 task_flags:0x400000 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7193 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x16c/0x340 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 44 41 01 11 <48> 3b 44 24 58 0f 85 e5 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e RSP: 0000:ffffc9000b74f178 EFLAGS: 00000206 RAX: bbbb3ef37588ed00 RBX: 0000000000000000 RCX: bbbb3ef37588ed00 RDX: 00000000e56347a1 RSI: ffffffff8db7ed49 RDI: ffffffff8be07960 RBP: ffffffff81742f85 R08: ffffffff81742f85 R09: ffffffff8e13f2e0 R10: ffffc9000b74f338 R11: ffffffff81ad9d50 R12: 0000000000000002 R13: ffffffff8e13f2e0 R14: 0000000000000000 R15: 0000000000000246 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+0xc2/0x23d0 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 save_stack+0xf5/0x1f0 mm/page_owner.c:165 __set_page_owner+0x8d/0x4c0 mm/page_owner.c:341 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x234/0x290 mm/page_alloc.c:1857 prep_new_page mm/page_alloc.c:1865 [inline] get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3915 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2486 folio_alloc_mpol_noprof mm/mempolicy.c:2505 [inline] vma_alloc_folio_noprof+0xe4/0x200 mm/mempolicy.c:2540 folio_prealloc+0x30/0x180 mm/memory.c:-1 alloc_anon_folio mm/memory.c:5165 [inline] do_anonymous_page mm/memory.c:5222 [inline] do_pte_missing+0x14e8/0x3330 mm/memory.c:4399 handle_pte_fault mm/memory.c:6273 [inline] __handle_mm_fault mm/memory.c:6411 [inline] handle_mm_fault+0x1b26/0x32b0 mm/memory.c:6580 do_user_addr_fault+0xa7c/0x1380 arch/x86/mm/fault.c:1336 handle_page_fault arch/x86/mm/fault.c:1476 [inline] exc_page_fault+0x82/0x100 arch/x86/mm/fault.c:1532 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7f8c8bd2a7a1 RSP: 002b:00007fffaaa30bd0 EFLAGS: 00010206 RAX: 00007f8c8ba20000 RBX: 0000000000000006 RCX: 0000000000000005 RDX: 00007f8c8bd50df3 RSI: 00007fffaaa30da0 RDI: 00007f8c8ba20000 RBP: 00007fffaaa311d0 R08: 00000000ffffffff R09: 0000000000000000 R10: 0000000000000022 R11: 0000000000000246 R12: 00007fffaaa30c70 R13: 0000000000000000 R14: 00007f8c8bd1d0c0 R15: 00007f8c8ba20000 task:syz-executor state:R running task stack:19496 pid:5823 tgid:5823 ppid:5818 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7050 preempt_schedule+0xae/0xc0 kernel/sched/core.c:7074 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] copy_pte_range mm/memory.c:1331 [inline] copy_pmd_range+0x7773/0x8060 mm/memory.c:1392 copy_pud_range mm/memory.c:1429 [inline] copy_p4d_range mm/memory.c:1453 [inline] copy_page_range+0xb88/0x11d0 mm/memory.c:1535 dup_mmap+0xf4a/0x1b80 mm/mmap.c:1827 dup_mm kernel/fork.c:1533 [inline] copy_mm+0x14f/0x770 kernel/fork.c:1585 copy_process+0x165d/0x3950 kernel/fork.c:2225 kernel_clone+0x21e/0x820 kernel/fork.c:2655 __do_sys_clone kernel/fork.c:2796 [inline] __se_sys_clone kernel/fork.c:2780 [inline] __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2780 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f68b8f85e93 RSP: 002b:00007ffde5757cd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f68b8f85e93 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 000055555d4d97d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 000000000001dd52 R15: 00007ffde5757e70 rcu: rcu_preempt kthread starved for 10698 jiffies! g12797 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:27128 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 __schedule_loop kernel/sched/core.c:6948 [inline] schedule+0x165/0x360 kernel/sched/core.c:6963 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+0x599/0xb30 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: 1 UID: 0 PID: 0 Comm: swapper/1 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+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: cc cc cc cc cc cc cc 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 33 9e 2a 00 f3 0f 1e fa fb f4 48 ee 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90000197de0 EFLAGS: 000002c6 RAX: 9a9af686f85b1900 RBX: ffffffff819786ba RCX: 9a9af686f85b1900 RDX: 0000000000000001 RSI: ffffffff8d997e54 RDI: ffffffff8be07960 RBP: ffffc90000197f10 R08: ffff8880b87336db R09: 1ffff110170e66db R10: dffffc0000000000 R11: ffffed10170e66dc R12: ffffffff8fa22f70 R13: 1ffff11003b56b70 R14: 0000000000000001 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888125d25000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f233cd72a60 CR3: 000000007eba2000 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+0x73/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x1ea/0x520 kernel/sched/idle.c:332 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x147