INFO: task syz.0.611:2312 blocked for more than 123 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.611 state:D stack:0 pid:2312 tgid:2312 ppid:297 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:6026 [inline]
__schedule+0x1399/0x1fa0 kernel/sched/core.c:7880
__schedule_loop kernel/sched/core.c:7961 [inline]
schedule+0xc5/0x240 kernel/sched/core.c:7976
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+0x369/0x650 kernel/sched/completion.c:127
wait_for_completion+0x1c/0x40 kernel/sched/completion.c:148
rcu_barrier+0x415/0x540 kernel/rcu/tree.c:4657
netdev_run_todo+0x118/0xce0 net/core/dev.c:10900
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+0x1fe/0xa00 fs/file_table.c:429
____fput+0x20/0x30 fs/file_table.c:457
task_work_run+0x1e5/0x260 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: 0033:0x7fc7e6b9cdd9
RSP: 002b:00007ffcde0640c8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007fc7e6e17da0 RCX: 00007fc7e6b9cdd9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007fc7e6e17da0 R08: 00007fc7e6e16218 R09: 0000000000000000
R10: 00000000003ffc68 R11: 0000000000000246 R12: 00000000000256b9
R13: 00007fc7e6e1618c R14: 000000000002555a R15: 00007ffcde0641d0
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 f1e96da778e106ed2ad9fef94b5d954a2cba2451
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
__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+0xdad/0xf00 kernel/hung_task.c:423
kthread+0x2c9/0x370 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
Sending NMI from CPU 1 to CPUs 0:
net_ratelimit: 113877 callbacks suppressed
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:1a:d5:7a:c3:2a, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:1a:d5:7a:c3:2a, vlan:0)
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 20 Comm: rcuop/0 Not tainted syzkaller #0 f1e96da778e106ed2ad9fef94b5d954a2cba2451
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:get_current arch/x86/include/asm/current.h:49 [inline]
RIP: 0010:get_stack_info_noinstr+0x25/0x130 arch/x86/kernel/dumpstack_64.c:176
Code: 90 90 90 90 90 66 0f 1f 00 55 48 89 e5 41 57 41 56 41 55 41 54 53 49 89 d6 49 89 f4 49 89 ff e8 21 01 00 00 b3 01 84 c0 75 0f <65> 48 8b 05 33 2c 5d 7a 49 39 c4 74 14 31 db 89 d8 5b 41 5c 41 5d
RSP: 0018:ffffc90000007060 EFLAGS: 00000246
RAX: ffff888103663900 RBX: ffffc90000007101 RCX: ffffc90000140000
RDX: ffffc90000007148 RSI: ffffc90000148000 RDI: ffffc90000007138
RBP: ffffc90000007088 R08: ffffc90000007100 R09: 0000000000000000
R10: ffffc90000007148 R11: fffff52000000e35 R12: ffff888103663900
R13: ffffc90000007138 R14: ffffc90000007148 R15: ffffc90000007138
FS: 0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fedd9547e20 CR3: 000000010b3fa000 CR4: 00000000003526b0
Call Trace:
get_stack_info+0x3e/0x100 arch/x86/kernel/dumpstack_64.c:199
__unwind_start+0x20b/0x410 arch/x86/kernel/unwind_frame.c:405
unwind_start arch/x86/include/asm/unwind.h:64 [inline]
arch_stack_walk+0xf2/0x170 arch/x86/kernel/stacktrace.c:24
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+0x40/0x50 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_node_noprof+0x1ca/0x420 mm/slub.c:4305
kmalloc_reserve+0xcf/0x4f0 net/core/skbuff.c:596
__alloc_skb+0x144/0x370 net/core/skbuff.c:687
alloc_skb include/linux/skbuff.h:1363 [inline]
nlmsg_new include/net/netlink.h:1015 [inline]
fdb_notify+0x78/0x150 net/bridge/br_fdb.c:195
br_fdb_update+0x4b7/0x680 net/bridge/br_fdb.c:945
br_handle_frame_finish+0x399/0x17a0 net/bridge/br_input.c:141
nf_hook_bridge_pre net/bridge/br_input.c:301 [inline]
br_handle_frame+0x5a6/0xba0 net/bridge/br_input.c:424
__netif_receive_skb_core+0xfae/0x3ab0 net/core/dev.c:5683
__netif_receive_skb_one_core net/core/dev.c:5787 [inline]
__netif_receive_skb net/core/dev.c:5902 [inline]
process_backlog+0x3e5/0xad0 net/core/dev.c:6238
__napi_poll+0xd0/0x610 net/core/dev.c:6889
napi_poll net/core/dev.c:6958 [inline]
net_rx_action+0x5ea/0xd80 net/core/dev.c:7080
handle_softirqs+0x1aa/0x630 kernel/softirq.c:621
__do_softirq+0xf/0x16 kernel/softirq.c:659
do_softirq+0xb8/0x110 kernel/softirq.c:503
__local_bh_enable_ip+0x74/0x80 kernel/softirq.c:430
local_bh_enable include/linux/bottom_half.h:33 [inline]
rcu_do_batch+0x5d9/0xd40 kernel/rcu/tree.c:2594
nocb_cb_wait kernel/rcu/tree_nocb.h:923 [inline]
rcu_nocb_cb_kthread+0x524/0xb30 kernel/rcu/tree_nocb.h:957
kthread+0x2c9/0x370 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
net_ratelimit: 95399 callbacks suppressed
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:1a:d5:7a:c3:2a, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:1a:d5:7a:c3:2a, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)