syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1):
 P7733/1:b..l

rcu: 	(detected by 1, t=10502 jiffies, g=37857, q=434 ncpus=2)
task:syz.4.521       state:R
  running task     stack:25976 pid:7733  tgid:7730  ppid:5641   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5510 [inline]
 __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7556
 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
 irqentry_exit+0x14f/0x8f0 kernel/entry/common.c:167
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:lock_acquire+0x221/0x350 kernel/locking/lockdep.c:5872
Code: ff ff ff e8 41 a0 12 0a f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 2b eb 9d 11 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 10 a1 15 0a cc 48 8d 3d 78 71 94
RSP: 0018:ffffc90004647448 EFLAGS: 00000286

RAX: 2d0e163ffe1fa500 RBX: 0000000000000000 RCX: 0000000000000046
RDX: 000000004faebf7a RSI: ffffffff8e25db1e RDI: ffffffff8c2ab780
RBP: ffffffff8176e21f R08: ffffffff8176e21f R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff8e959c20 R12: 0000000000000002
R13: ffffffff8e959c20 R14: 0000000000000000 R15: 0000000000000246
 rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 rcu_read_lock include/linux/rcupdate.h:840 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1183 [inline]
 unwind_next_frame+0xac/0x2550 arch/x86/kernel/unwind_orc.c:495
 __unwind_start+0x514/0x660 arch/x86/kernel/unwind_orc.c:787
 unwind_start arch/x86/include/asm/unwind.h:64 [inline]
 arch_stack_walk+0xe3/0x150 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
 ref_tracker_alloc+0x1b0/0x4b0 lib/ref_tracker.c:276
 __netdev_tracker_alloc include/linux/netdevice.h:4499 [inline]
 netdev_hold include/linux/netdevice.h:4528 [inline]
 neigh_parms_alloc+0x1ee/0x500 net/core/neighbour.c:1773
 ipv6_add_dev+0x40d/0x13a0 net/ipv6/addrconf.c:403
 addrconf_notify+0x771/0x1050 net/ipv6/addrconf.c:3685
 notifier_call_chain+0x1a5/0x3d0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2288 [inline]
 call_netdevice_notifiers net/core/dev.c:2302 [inline]
 register_netdevice+0x18a4/0x1eb0 net/core/dev.c:11478
 register_netdev+0x40/0x60 net/core/dev.c:11556
 ip6gre_init_net+0x28f/0x3b0 net/ipv6/ip6_gre.c:1609
 ops_init+0x35d/0x5d0 net/core/net_namespace.c:137
 setup_net+0x118/0x350 net/core/net_namespace.c:446
 copy_net_ns+0x4f9/0x720 net/core/net_namespace.c:579
 create_new_namespaces+0x3f0/0x6b0 kernel/nsproxy.c:132
 unshare_nsproxy_namespaces+0x149/0x190 kernel/nsproxy.c:234
 ksys_unshare+0x57d/0xa00 kernel/fork.c:3268
 __do_sys_unshare kernel/fork.c:3342 [inline]
 __se_sys_unshare kernel/fork.c:3340 [inline]
 __x64_sys_unshare+0x38/0x50 kernel/fork.c:3340
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd1b8b9ce59
RSP: 002b:00007fd1b6dd5028 EFLAGS: 00000246
 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00007fd1b8e16180 RCX: 00007fd1b8b9ce59
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000042060680
RBP: 00007fd1b8c32e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd1b8e16218 R14: 00007fd1b8e16180 R15: 00007fd1b8f3fa48
 </TASK>
rcu: rcu_preempt kthread starved for 9878 jiffies! g37857 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:27496 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5510 [inline]
 __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234
 __schedule_loop kernel/sched/core.c:7311 [inline]
 schedule+0x164/0x2b0 kernel/sched/core.c:7326
 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2123
 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
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 05/09/2026
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64
Code: ac 75 02 e9 13 05 03 00 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 f3 b9 14 00 fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90
RSP: 0018:ffffc90000197e40 EFLAGS: 00000246

RAX: 0000000000340ed1 RBX: ffffffff819aa25c RCX: 0000000080000001
RDX: 0000000000000001 RSI: ffffffff8dfe3478 RDI: ffffffff8c2ab780
RBP: ffffc90000197f10 R08: ffff8880b87338db R09: 1ffff110170e671b
R10: dffffc0000000000 R11: ffffed10170e671c R12: 0000000000000000
R13: 1ffff11003bd4000 R14: 1ffff92000032fd0 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff888125320000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb20427c9c1 CR3: 00000000787f0000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000001 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/kernel/process.c:767 [inline]
 default_idle+0x9/0x20 arch/x86/kernel/process.c:768
 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:199 [inline]
 do_idle+0x1cc/0x540 kernel/sched/idle.c:355
 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:454
 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312
 common_startup_64+0x13e/0x157
 </TASK>
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - urb shutting down with status: -2
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - nonzero urb status received: -71
usb 2-1: pegasus_irq - usb_submit_urb failed with result -19