Description: cifs: fix use-after-free caused by invalid pointer `hostname`
References:
 https://bugzilla.redhat.com/show_bug.cgi?id=2154171
Notes:
 carnil> Commit fixes 7be3248f3139 ("cifs: To match file servers, make
 carnil> sure the server hostname matches") in 5.16-rc1 (and backported
 carnil> to 5.15.3, 5.14.19).
Bugs:
upstream: released (6.1-rc3) [153695d36ead0ccc4d0256953c751cabf673e621]
6.1-upstream-stable: N/A "Fixed before branching point"
5.10-upstream-stable: N/A "Vulnerable code not present"
4.19-upstream-stable: N/A "Vulnerable code not present"
sid: released (6.1.4-1)
5.10-bullseye-security: N/A "Vulnerable code not present"
4.19-buster-security: N/A "Vulnerable code not present"