[syzbot] [net?] INFO: task hung in inet6_rtm_newaddr (2)

[syzbot <syzbot+101224300649c3eb8af4@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    01f95500a162 Merge tag 'uml-for-linux-6.15-rc6' of git://g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13c0b0f4580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=91c351a0f6229e67
dashboard link: https://syzkaller.appspot.com/bug?extid=101224300649c3eb8af4
compiler:       Debian clang version 20.1.2 (++20250402124445+58df0ef89dd6-1~exp1~20250402004600.97), Debian LLD 20.1.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1223bb68580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-01f95500.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/db1628150472/vmlinux-01f95500.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ecd327744f2e/bzImage-01f95500.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+101224300649c3eb8af4@syzkaller.appspotmail.com

INFO: task syz-executor:5435 blocked for more than 143 seconds.
      Not tainted 6.15.0-rc5-syzkaller-00022-g01f95500a162 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:22056 pid:5435  tgid:5435  ppid:1      task_flags:0x400140 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x16e2/0x4cd0 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6860
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6917
 __mutex_lock_common kernel/locking/mutex.c:678 [inline]
 __mutex_lock+0x724/0xe80 kernel/locking/mutex.c:746
 rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 inet6_rtm_newaddr+0x5b7/0xd20 net/ipv6/addrconf.c:5028
 rtnetlink_rcv_msg+0x7cc/0xb70 net/core/rtnetlink.c:6955
 netlink_rcv_skb+0x219/0x490 net/netlink/af_netlink.c:2534
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0x758/0x8d0 net/netlink/af_netlink.c:1339
 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1883
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x219/0x270 net/socket.c:727
 __sys_sendto+0x3bd/0x520 net/socket.c:2180
 __do_sys_sendto net/socket.c:2187 [inline]
 __se_sys_sendto net/socket.c:2183 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2183
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff7979907fc
RSP: 002b:00007ffd90db52d0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007ff7986e4620 RCX: 00007ff7979907fc
RDX: 0000000000000040 RSI: 00007ff7986e4670 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007ffd90db5324 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 0000000000000000 R14: 00007ff7986e4670 R15: 0000000000000000
 </TASK>
INFO: task syz-executor:5442 blocked for more than 152 seconds.
      Not tainted 6.15.0-rc5-syzkaller-00022-g01f95500a162 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:21848 pid:5442  tgid:5442  ppid:1      task_flags:0x400140 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x16e2/0x4cd0 kernel/sched/core.c:6767


---
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