syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P13948/1:b..l P14068/1:b..l P14069/1:b..l P8573/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=72453, q=400 ncpus=2)
task:kworker/u8:26   state:R  running task     stack:22264 pid:8573  tgid:8573  ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
 preempt_schedule_notrace+0x57/0x90 kernel/sched/core.c:7140
 preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13
 rcu_is_watching+0x7f/0xb0 kernel/rcu/tree.c:752
 rcu_read_unlock include/linux/rcupdate.h:895 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1195 [inline]
 unwind_next_frame+0x1a6d/0x23d0 arch/x86/kernel/unwind_orc.c:695
 __unwind_start+0x5b9/0x760 arch/x86/kernel/unwind_orc.c:773
 unwind_start arch/x86/include/asm/unwind.h:64 [inline]
 arch_stack_walk+0xe4/0x150 arch/x86/kernel/stacktrace.c:24
 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+0xee/0x890 kernel/rcu/tree.c:3239
 kernfs_put+0x18e/0x470 fs/kernfs/dir.c:591
 sysfs_put include/linux/sysfs.h:808 [inline]
 __kobject_del+0xe9/0x330 lib/kobject.c:605
 kobject_del+0x45/0x60 lib/kobject.c:627
 nfs_netns_sysfs_destroy+0x5c/0xb0 fs/nfs/sysfs.c:214
 nfs_clients_exit+0x4e/0x170 fs/nfs/client.c:1283
 ops_exit_list net/core/net_namespace.c:199 [inline]
 ops_undo_list+0x49a/0x990 net/core/net_namespace.c:252
 cleanup_net+0x4d8/0x7a0 net/core/net_namespace.c:696
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
task:syz.4.2045      state:R  running task     stack:26368 pid:14069 tgid:14066 ppid:11019  task_flags:0x400140 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7190
 irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x222/0x340 kernel/locking/lockdep.c:5872
Code: ff ff ff e8 20 b1 bb 09 f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 0a 20 e2 10 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 da 50 72 ff cc 48 8d 3d 37 78 e7
RSP: 0018:ffffc90003ddf8e8 EFLAGS: 00000286
RAX: 8cd801f23c15c900 RBX: 0000000000000000 RCX: 0000000000000046
RDX: 000000009b256778 RSI: ffffffff8d976049 RDI: ffffffff8bc08360
RBP: ffffffff821336b9 R08: ffffffff821336b9 R09: ffffffff8df41aa0
R10: dffffc0000000000 R11: ffffed10066cc7a1 R12: 0000000000000002
R13: ffffffff8df41aa0 R14: 0000000000000000 R15: 0000000000000246
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:867 [inline]
 ___pte_offset_map+0x45/0x240 mm/pgtable-generic.c:288
 __pte_offset_map include/linux/mm.h:3346 [inline]
 __pte_offset_map_lock+0x46/0x210 mm/pgtable-generic.c:399
 pte_offset_map_lock include/linux/mm.h:3361 [inline]
 follow_page_pte+0xc4/0x13e0 mm/gup.c:812
 follow_pmd_mask mm/gup.c:-1 [inline]
 follow_pud_mask mm/gup.c:967 [inline]
 follow_p4d_mask mm/gup.c:984 [inline]
 follow_page_mask mm/gup.c:1023 [inline]
 __get_user_pages+0xa6c/0x29f0 mm/gup.c:1426
 populate_vma_page_range+0x29f/0x3a0 mm/gup.c:1860
 __mm_populate+0x24c/0x380 mm/gup.c:1963
 mm_populate include/linux/mm.h:3701 [inline]
 vm_mmap_pgoff+0x387/0x4d0 mm/util.c:586
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f21aa18f749
RSP: 002b:00007f21ab08f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f21aa3e5fa0 RCX: 00007f21aa18f749
RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000200000000000
RBP: 00007f21aa213f91 R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f21aa3e6038 R14: 00007f21aa3e5fa0 R15: 00007ffe64c4f2c8
 </TASK>
task:syz.0.2046      state:R  running task     stack:27264 pid:14068 tgid:14068 ppid:9345   task_flags:0x40004c flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7047
 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+0x38bc/0x4170 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:1173
 exit_mm+0x169/0x230 kernel/exit.c:581
 do_exit+0x627/0x22f0 kernel/exit.c:959
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1112
 __do_sys_exit_group kernel/exit.c:1123 [inline]
 __se_sys_exit_group kernel/exit.c:1121 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1121
 x64_sys_call+0x2210/0x2210 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5229b8f749
RSP: 002b:00007ffef2983158 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f5229b8f749
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffef29831bc R08: 00000006f298324f R09: 00000000000927c0
R10: 0000000000000001 R11: 0000000000000246 R12: 00000000000000e3
R13: 00000000000927c0 R14: 0000000000117097 R15: 00007ffef2983210
 </TASK>
task:syz-executor    state:R  running task     stack:22392 pid:13948 tgid:13948 ppid:13934  task_flags:0x400140 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7190
 irqentry_exit+0x5e3/0x670 kernel/entry/common.c:216
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_release+0x2d8/0x3b0 kernel/locking/lockdep.c:5893
Code: 34 e2 10 00 00 00 00 eb b5 e8 84 7f bb 09 f7 c3 00 02 00 00 74 b9 65 48 8b 05 74 ee e1 10 48 3b 44 24 28 75 44 fb 48 83 c4 30 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 44 1f 72 ff cc 48 8d 3d 11 4a e7
RSP: 0018:ffffc90003b1e940 EFLAGS: 00000282
RAX: 26700bbe3d141200 RBX: 0000000000000202 RCX: 0000000000000046
RDX: 0000000000000002 RSI: ffffffff8d976049 RDI: ffffffff8bc08360
RBP: ffff888067fb6700 R08: ffffc90003b1fb50 R09: ffffc90003b1ea98
R10: dffffc0000000000 R11: fffff52000763d55 R12: 0000000000000002
R13: 0000000000000002 R14: ffffffff8df41aa0 R15: ffff888067fb5b80
 rcu_lock_release include/linux/rcupdate.h:341 [inline]
 rcu_read_unlock include/linux/rcupdate.h:897 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1195 [inline]
 unwind_next_frame+0x1ab1/0x23d0 arch/x86/kernel/unwind_orc.c:695
 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:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x3e2/0x700 mm/slub.c:5776
 kmalloc_noprof include/linux/slab.h:957 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 mctp_add_dev+0x6b/0x250 net/mctp/device.c:338
 mctp_register net/mctp/device.c:450 [inline]
 mctp_dev_notify+0x28b/0x300 net/mctp/device.c:465
 notifier_call_chain+0x19d/0x3a0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2268 [inline]
 call_netdevice_notifiers net/core/dev.c:2282 [inline]
 register_netdevice+0x15bd/0x1a70 net/core/dev.c:11431
 wg_newlink+0x391/0x670 drivers/net/wireguard/device.c:372
 rtnl_newlink_create+0x310/0xb00 net/core/rtnetlink.c:3840
 __rtnl_newlink net/core/rtnetlink.c:3957 [inline]
 rtnl_newlink+0x16e7/0x1c90 net/core/rtnetlink.c:4072
 rtnetlink_rcv_msg+0x7cf/0xb70 net/core/rtnetlink.c:6958
 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2550
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0x21c/0x270 net/socket.c:742
 __sys_sendto+0x3bd/0x520 net/socket.c:2206
 __do_sys_sendto net/socket.c:2213 [inline]
 __se_sys_sendto net/socket.c:2209 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2209
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fea1fb915dc
RSP: 002b:00007ffe26b2d910 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007fea20914620 RCX: 00007fea1fb915dc
RDX: 000000000000003c RSI: 00007fea20914670 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007ffe26b2d964 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000000 R14: 00007fea20914670 R15: 0000000000000000
 </TASK>
rcu: rcu_preempt kthread starved for 10677 jiffies! g72453 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:27568 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863
 __schedule_loop kernel/sched/core.c:6945 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6960
 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+0x510/0xa50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
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: 1e a4 b6 f5 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 53 b1 0e 00 f3 0f 1e fa fb f4 <e9> f3 a3 b6 f5 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90000197e20 EFLAGS: 000002c6
RAX: 0000000001d0504d RBX: ffffffff819713ee RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8d792135 RDI: ffffffff8bc08360
RBP: ffffc90000197f10 R08: ffff8880b87336db R09: 1ffff110170e66db
R10: dffffc0000000000 R11: ffffed10170e66dc R12: ffffffff8f822370
R13: 1ffff1100385fb70 R14: 0000000000000001 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff888125f1f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b32a15ff8 CR3: 0000000079b64000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 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+0x1be/0x4d0 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
 </TASK>