syzbot

INFO: task syz-executor:2061 blocked for more than 122 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:0     pid:2061  tgid:2061  ppid:1      flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6016 [inline]
 __schedule+0x1399/0x1fa0 kernel/sched/core.c:7870
 __schedule_loop kernel/sched/core.c:7951 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7966
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:8023
 __mutex_lock_common kernel/locking/mutex.c:707 [inline]
 __mutex_lock+0x960/0x1bb0 kernel/locking/mutex.c:803
 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1134
 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285
 rtnl_lock net/core/rtnetlink.c:79 [inline]
 rtnetlink_rcv_msg+0x79e/0xa40 net/core/rtnetlink.c:6672
 netlink_rcv_skb+0x256/0x4f0 net/netlink/af_netlink.c:2545
 rtnetlink_rcv+0x20/0x30 net/core/rtnetlink.c:6693
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0x8c0/0xa60 net/netlink/af_netlink.c:1339
 netlink_sendmsg+0x7fe/0xb10 net/netlink/af_netlink.c:1889
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 __sys_sendto+0x718/0x790 net/socket.c:2216
 __do_sys_sendto net/socket.c:2228 [inline]
 __se_sys_sendto net/socket.c:2224 [inline]
 __x64_sys_sendto+0xe9/0x100 net/socket.c:2224
 x64_sys_call+0x2c2c/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:45
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f0631757997
RSP: 002b:00007ffe7c76ff80 EFLAGS: 00000202 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 000055556de16500 RCX: 00007f0631757997
RDX: 0000000000000028 RSI: 00007f0632544670 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00007ffe7c76ffe4 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000003
R13: 0000000000000000 R14: 00007f0632544670 R15: 0000000000000000
 </TASK>
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 f39b5fd6571327469eae9f28eb29c870797b656b
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
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+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
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 9 Comm: kworker/0:0 Not tainted syzkaller #0 f39b5fd6571327469eae9f28eb29c870797b656b
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Workqueue: mld mld_query_work
RIP: 0010:arch_stack_walk+0x129/0x170 arch/x86/kernel/stacktrace.c:27
Code: ff ff ff 4c 89 ff e8 56 95 06 00 48 85 c0 74 32 48 89 df 48 89 c6 4d 89 f3 41 ba 8a 95 9c d8 45 03 53 f1 74 02 0f 0b 41 ff d3 <0f> 1f 00 84 c0 74 11 4c 89 ff e8 78 96 06 00 83 bd 78 ff ff ff 00
RSP: 0018:ffffc900000976a8 EFLAGS: 00000282
RAX: 0000000000000001 RBX: ffffc90000097760 RCX: 0000000000097600
RDX: dffffc0000000000 RSI: ffffffff84ff48cb RDI: ffffc90000097760
RBP: ffffc90000097730 R08: ffffc90000097770 R09: ffffc90000097768
R10: 0000000000000006 R11: ffffffff8175d800 R12: ffff888102655f00
R13: 0000000000000000 R14: ffffffff8175d800 R15: ffffc900000976a8
FS:  0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f05e8547e20 CR3: 00000000074a8000 CR4: 00000000003526b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 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_free_info+0x4a/0x60 mm/kasan/generic.c:579
 poison_slab_object mm/kasan/common.c:249 [inline]
 __kasan_slab_free+0x5f/0x80 mm/kasan/common.c:266
 kasan_slab_free include/linux/kasan.h:234 [inline]
 slab_free_hook mm/slub.c:2445 [inline]
 slab_free mm/slub.c:4714 [inline]
 kmem_cache_free+0x1bd/0x4f0 mm/slub.c:4825
 kfree_skbmem net/core/skbuff.c:-1 [inline]
 __kfree_skb+0x18f/0x210 net/core/skbuff.c:1203
 consume_skb+0x65/0x1a0 net/core/skbuff.c:1434
 __mld_query_work net/ipv6/mcast.c:1504 [inline]
 mld_query_work+0xcfb/0x2c50 net/ipv6/mcast.c:1532
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x7d1/0x1020 kernel/workqueue.c:3319
 worker_thread+0xc70/0x10b0 kernel/workqueue.c:3400
 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
 </TASK>
net_ratelimit: 112994 callbacks suppressed
bridge0: received packet on veth1_to_bridge with own address as source address (addr:c6:17:d9:98:48:2c, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:c6:17:d9:98:48:2c, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:c6:17:d9:98:48:2c, vlan:0)
net_ratelimit: 118757 callbacks suppressed
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:c6:17:d9:98:48:2c, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth1_to_bridge with own address as source address (addr:c6:17:d9:98:48:2c, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:1c, vlan:0)
bridge0: received packet on bridge_slave_1 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)