Hi all,
Since updating to 6.0.16 the bind() system call no longer fails with EADDRINUSE when the address is already in use. Instead bind() returns 1 in such a case, which is not a valid return value for this system call.
It works with the 6.0.15 kernel and earlier, 6.1.4 and 6.2-rc3 also seem to work.
Fedora bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2159066
To reproduce you can just run `ncat -l 5000` two times, the second one should fail. However it just uses a random port instead.
As far as I can tell this problem is caused by https://lore.kernel.org/stable/20221228144337.512799851@linuxfoundation.org/ which did not backport commit 7a7160edf1bf properly. The line `int ret = -EADDRINUSE, port = snum, l3mdev;` is missing in net/ipv4/inet_connection_sock.c. This is the working 6.1 patch: https://lore.kernel.org/all/20221228144339.969733443@linuxfoundation.org/
Best regards, Paul