syzbot

INFO: task syz.2.142:861 blocked for more than 127 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.142       state:D stack:0     pid:861   tgid:861   ppid:296    flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6054 [inline]
 __schedule+0x1496/0x20b0 kernel/sched/core.c:7867
 __schedule_loop kernel/sched/core.c:7944 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7959
 schedule_timeout+0xc7/0x3b0 kernel/time/timer.c:2596
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common kernel/sched/completion.c:116 [inline]
 wait_for_common+0x368/0x650 kernel/sched/completion.c:127
 wait_for_completion+0x1c/0x40 kernel/sched/completion.c:148
 rcu_barrier+0x45a/0x580 kernel/rcu/tree.c:4657
 netdev_run_todo+0x118/0xce0 net/core/dev.c:10912
 rtnl_unlock+0x12/0x20 net/core/rtnetlink.c:152
 tun_detach drivers/net/tun.c:704 [inline]
 tun_chr_close+0xc5/0x150 drivers/net/tun.c:3520
 __fput+0x20b/0xa30 fs/file_table.c:447
 ____fput+0x20/0x30 fs/file_table.c:475
 task_work_run+0x1e8/0x260 kernel/task_work.c:246
 exit_task_work include/linux/task_work.h:43 [inline]
 do_exit+0xa46/0x2850 kernel/exit.c:955
 do_group_exit+0x21f/0x2f0 kernel/exit.c:1098
 get_signal+0x134c/0x1490 kernel/signal.c:2933
 arch_do_signal_or_restart+0xbc/0x700 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x57/0xb0 kernel/entry/common.c:218
 do_syscall_64+0x63/0xf0 arch/x86/entry/common.c:84
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f583715e6ce
RSP: 002b:00007f58380aff58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6
RAX: fffffffffffffdfc RBX: 00007f58380b06c0 RCX: 00007f583715e6ce
RDX: 00007f58380affb0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f5837233eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5837426038 R14: 00007f5837425fa0 R15: 00007ffc2e295b08
 </TASK>
INFO: task syz.3.376:1744 blocked for more than 135 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.376       state:D stack:0     pid:1744  tgid:1744  ppid:293    flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6054 [inline]
 __schedule+0x1496/0x20b0 kernel/sched/core.c:7867
 __schedule_loop kernel/sched/core.c:7944 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7959
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:8016
 __mutex_lock_common kernel/locking/mutex.c:707 [inline]
 __mutex_lock+0x902/0x1b90 kernel/locking/mutex.c:806
 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1136
 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285
 rcu_barrier+0x4d/0x580 kernel/rcu/tree.c:4589
 kvm_mmu_uninit_tdp_mmu+0x1ea/0x210 arch/x86/kvm/mmu/tdp_mmu.c:51
 kvm_mmu_uninit_vm+0x27/0x60 arch/x86/kvm/mmu/mmu.c:6569
 kvm_arch_destroy_vm+0x395/0x410 arch/x86/kvm/x86.c:13008
 kvm_destroy_vm virt/kvm/kvm_main.c:1355 [inline]
 kvm_put_kvm+0xadf/0x12d0 virt/kvm/kvm_main.c:1392
 kvm_vm_release+0x47/0x70 virt/kvm/kvm_main.c:1415
 __fput+0x20b/0xa30 fs/file_table.c:447
 ____fput+0x20/0x30 fs/file_table.c:475
 task_work_run+0x1e8/0x260 kernel/task_work.c:246
 resume_user_mode_work+0x35/0x50 include/linux/resume_user_mode.h:50
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x63/0xb0 kernel/entry/common.c:218
 do_syscall_64+0x63/0xf0 arch/x86/entry/common.c:84
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7fbff5f9de99
RSP: 002b:00007ffeaccfae88 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007fbff6227da0 RCX: 00007fbff5f9de99
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007fbff6227da0 R08: 0000000000000006 R09: 0000000000000000
R10: 00007fbff6227cb0 R11: 0000000000000246 R12: 0000000000015269
R13: 00007fbff622609c R14: 000000000001500e R15: 00007ffeaccfaf90
 </TASK>
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 5adf726ab28801c07fd45706e49e1b3a66128c4b
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:94
 dump_stack_lvl+0x140/0x1c0 lib/dump_stack.c:120
 dump_stack+0x19/0x20 lib/dump_stack.c:129
 nmi_cpu_backtrace+0x2ba/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x142/0x2c0 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:41
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:267 [inline]
 watchdog+0xe45/0xf90 kernel/hung_task.c:423
 kthread+0x2c7/0x360 kernel/kthread.c:389
 ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 33 Comm: rcuop/1 Not tainted syzkaller #0 5adf726ab28801c07fd45706e49e1b3a66128c4b
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:update_stack_state+0x40f/0x4d0 arch/x86/kernel/unwind_frame.c:-1
Code: 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 d8 89 9b 00 4d 8b 36 48 8b 5d d0 48 83 c3 48 48 89 d8 48 c1 e8 03 42 80 3c 38 00 <74> 08 48 89 df e8 d7 8a 9b 00 4c 89 33 43 80 7c 3d 00 00 48 8b 5d
RSP: 0018:ffffc90000230108 EFLAGS: 00000246
RAX: 1ffff9200004604e RBX: ffffc90000230270 RCX: ffffc90000230701
RDX: ffffc90000230750 RSI: 1ffff92000046046 RDI: ffffc90000230250
RBP: ffffc900002301b8 R08: ffffc900002302f0 R09: ffffc900002302e8
R10: 0000000000000005 R11: ffffffff81759d20 R12: ffffc90000230280
R13: 1ffff9200004604d R14: ffffffff85153217 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005647b9c651f0 CR3: 00000001219a8000 CR4: 00000000003526b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 00000000fda3b69a DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 unwind_next_frame+0x39e/0x6b0 arch/x86/kernel/unwind_frame.c:315
 arch_stack_walk+0x138/0x170 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:49 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:70
 kasan_save_alloc_info+0x3a/0x50 mm/kasan/generic.c:565
 unpoison_slab_object mm/kasan/common.c:321 [inline]
 __kasan_slab_alloc+0x73/0x90 mm/kasan/common.c:347
 kasan_slab_alloc include/linux/kasan.h:251 [inline]
 slab_post_alloc_hook mm/slub.c:4202 [inline]
 slab_alloc_node mm/slub.c:4251 [inline]
 kmem_cache_alloc_noprof+0x1bf/0x410 mm/slub.c:4260
 skb_clone+0x21d/0x470 net/core/skbuff.c:2079
 deliver_clone net/bridge/br_forward.c:125 [inline]
 maybe_deliver net/bridge/br_forward.c:191 [inline]
 br_flood+0x4df/0x720 net/bridge/br_forward.c:237
 br_handle_frame_finish+0x1157/0x1620 net/bridge/br_input.c:215
 nf_hook_bridge_pre net/bridge/br_input.c:301 [inline]
 br_handle_frame+0x5a5/0xba0 net/bridge/br_input.c:424
 __netif_receive_skb_core+0xfc4/0x3a70 net/core/dev.c:5695
 __netif_receive_skb_one_core net/core/dev.c:5799 [inline]
 __netif_receive_skb net/core/dev.c:5914 [inline]
 process_backlog+0x40b/0xaf0 net/core/dev.c:6250
 __napi_poll+0xcd/0x600 net/core/dev.c:6901
 napi_poll net/core/dev.c:6970 [inline]
 net_rx_action+0x5dc/0xd70 net/core/dev.c:7092
 handle_softirqs+0x1aa/0x620 kernel/softirq.c:621
 __do_softirq+0xf/0x16 kernel/softirq.c:659
 do_softirq+0xb8/0x110 kernel/softirq.c:503
 </IRQ>