net: rose: lock the socket in rose_bind()

syzbot reported a soft lockup in rose_loopback_timer(),
with a repro calling bind() from multiple threads.

rose_bind() must lock the socket to avoid this issue.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Reported-by:  <syzbot+7ff41b5215f0c534534e@syzkaller.appspotmail.com>
Closes: https://lore.kernel.org/netdev/67a0f78d.050a0220.d7c5a.00a0.GAE@google.com/T/#u


Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Link: https://patch.msgid.link/20250203170838.3521361-1-edumazet@google.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>