INFO: task syz.6.4259:10928 blocked for more than 124 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.4259 state:D stack:0 pid:10928 tgid:10927 ppid:2243 flags:0x00004006
Call Trace:
context_switch kernel/sched/core.c:5945 [inline]
__schedule+0x1322/0x1df0 kernel/sched/core.c:7791
__schedule_loop kernel/sched/core.c:7872 [inline]
schedule+0xc6/0x240 kernel/sched/core.c:7887
schedule_timeout+0xb2/0x3a0 kernel/time/timer.c:2595
do_wait_for_common kernel/sched/completion.c:95 [inline]
__wait_for_common kernel/sched/completion.c:116 [inline]
wait_for_common+0x359/0x630 kernel/sched/completion.c:127
wait_for_completion+0x1c/0x40 kernel/sched/completion.c:148
rcu_barrier+0x415/0x530 kernel/rcu/tree.c:4657
flush_rcu_work+0x71/0x90 kernel/workqueue.c:4292
kvfree_rcu_barrier+0x23c/0x2f0 kernel/rcu/tree.c:3955
kmem_cache_destroy+0x32/0x170 mm/slab_common.c:490
p9_client_destroy+0x42b/0x480 net/9p/client.c:1088
v9fs_session_close+0x52/0x1d0 fs/9p/v9fs.c:506
v9fs_kill_super+0x60/0x90 fs/9p/vfs_super.c:196
deactivate_locked_super+0xd5/0x2a0 fs/super.c:476
deactivate_super+0xb8/0xe0 fs/super.c:509
cleanup_mnt+0x3f1/0x480 fs/namespace.c:1370
__cleanup_mnt+0x1d/0x40 fs/namespace.c:1377
task_work_run+0x1e3/0x250 kernel/task_work.c:240
resume_user_mode_work+0x36/0x50 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+0x64/0xb0 kernel/entry/common.c:218
do_syscall_64+0x64/0xf0 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f9b9378eba9
RSP: 002b:00007f9b9467b038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: fffffffffffffffe RBX: 00007f9b939d5fa0 RCX: 00007f9b9378eba9
RDX: 0000200000000040 RSI: 0000200000000000 RDI: 0000000000000000
RBP: 00007f9b93811e19 R08: 0000200000000280 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9b939d6038 R14: 00007f9b939d5fa0 R15: 00007fff9e4e05b8
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 1113c6f757b896aae05d8aba828d71ec34ef4a9d
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
__dump_stack+0x21/0x30 lib/dump_stack.c:94
dump_stack_lvl+0x10c/0x190 lib/dump_stack.c:120
dump_stack+0x19/0x20 lib/dump_stack.c:129
nmi_cpu_backtrace+0x2bf/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+0xd8f/0xed0 kernel/hung_task.c:423
kthread+0x2c7/0x370 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 10976 Comm: syz.2.4291 Not tainted syzkaller #0 1113c6f757b896aae05d8aba828d71ec34ef4a9d
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:stack_trace_consume_entry+0x5/0x2a0 kernel/stacktrace.c:83
Code: 8d 65 f0 5b 41 5e 5d c3 cc cc cc cc cc e8 13 34 18 04 0f 1f 00 b8 46 bd a0 7c 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 <48> 89 e5 41 57 41 56 41 55 41 54 53 48 83 ec 20 48 ba 00 00 00 00
RSP: 0018:ffffc90000230158 EFLAGS: 00000257
RAX: ffffffff81dbf503 RBX: ffffc90000230220 RCX: 0000000000230100
RDX: ffffc90000230401 RSI: ffffffff81dbf503 RDI: ffffc90000230220
RBP: ffffc900002301f0 R08: ffffc90000230230 R09: ffffc90000230228
R10: 0000000000000000 R11: ffffffff81744550 R12: ffff88811cf7a600
R13: 0000000000082820 R14: ffffffff81744550 R15: ffffc90000230168
FS: 00007f44dc4426c0(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005617bfb4eb90 CR3: 0000000130ac8000 CR4: 00000000003526b0
DR0: 0000000000000000 DR1: 00000000fec00049 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
stack_trace_save+0x9d/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:48 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:69
kasan_save_alloc_info+0x40/0x50 mm/kasan/generic.c:565
unpoison_slab_object mm/kasan/common.c:320 [inline]
__kasan_slab_alloc+0x73/0x90 mm/kasan/common.c:346
kasan_slab_alloc include/linux/kasan.h:250 [inline]
slab_post_alloc_hook mm/slub.c:4169 [inline]
slab_alloc_node mm/slub.c:4218 [inline]
kmem_cache_alloc_node_noprof+0x139/0x3b0 mm/slub.c:4272
kmalloc_reserve+0xcf/0x500 net/core/skbuff.c:596
__alloc_skb+0x144/0x370 net/core/skbuff.c:687
alloc_skb include/linux/skbuff.h:1331 [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:941
br_handle_frame_finish+0x39c/0x1720 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+0xf4b/0x3940 net/core/dev.c:5651
__netif_receive_skb_one_core net/core/dev.c:5755 [inline]
__netif_receive_skb net/core/dev.c:5870 [inline]
process_backlog+0x3e5/0xae0 net/core/dev.c:6206
__napi_poll+0xd3/0x610 net/core/dev.c:6857
napi_poll net/core/dev.c:6926 [inline]
net_rx_action+0x584/0xce0 net/core/dev.c:7048
handle_softirqs+0x1ab/0x630 kernel/softirq.c:621
__do_softirq+0xf/0x16 kernel/softirq.c:659
do_softirq+0xa6/0x100 kernel/softirq.c:503
__local_bh_enable_ip+0x74/0x80 kernel/softirq.c:430
local_bh_enable include/linux/bottom_half.h:33 [inline]
ipt_do_table+0x136f/0x15a0 net/ipv4/netfilter/ip_tables.c:357
iptable_mangle_hook+0x1a8/0x500 net/ipv4/netfilter/iptable_mangle.c:80
nf_hook_entry_hookfn include/linux/netfilter.h:155 [inline]
nf_hook_slow+0xd2/0x240 net/netfilter/core.c:626
nf_hook include/linux/netfilter.h:272 [inline]
NF_HOOK_COND include/linux/netfilter.h:305 [inline]
ip_output+0x25f/0x2a0 net/ipv4/ip_output.c:434
dst_output include/net/dst.h:459 [inline]
ip_local_out net/ipv4/ip_output.c:130 [inline]
ip_send_skb+0x173/0x1b0 net/ipv4/ip_output.c:1496
udp_send_skb+0xa1b/0x1340 net/ipv4/udp.c:1041
udp_sendmsg+0x1640/0x21f0 net/ipv4/udp.c:1335
inet_sendmsg+0xef/0x120 net/ipv4/af_inet.c:858
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
____sys_sendmsg+0x82a/0xa70 net/socket.c:2610
___sys_sendmsg+0x220/0x2a0 net/socket.c:2664
__sys_sendmmsg+0x271/0x470 net/socket.c:2750
__do_sys_sendmmsg net/socket.c:2779 [inline]
__se_sys_sendmmsg net/socket.c:2776 [inline]
__x64_sys_sendmmsg+0xa4/0xc0 net/socket.c:2776
x64_sys_call+0xfec/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:308
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x58/0xf0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f44db58eba9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f44dc442038 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007f44db7d5fa0 RCX: 00007f44db58eba9
RDX: 000000000800001d RSI: 0000200000007fc0 RDI: 0000000000000003
RBP: 00007f44db611e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f44db7d6038 R14: 00007f44db7d5fa0 R15: 00007ffe927c6598
net_ratelimit: 113218 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 veth0_to_bridge with own address as source address (addr:26:cd:d0:5f:aa:e8, 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 30ªö»ôM with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:26:cd:d0:5f:aa:e8, vlan:0)
bridge0: received packet on 30ªö»ôM with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on 30ªö»ôM with own address as source address (addr:aa:aa:aa:aa:aa:0c, 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 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:0c, vlan:0)