Description: tty: n_gsm: fix the UAF caused by race condition in gsm_cleanup_mux
References:
 https://bugzilla.redhat.com/show_bug.cgi?id=2255498
Notes:
 carnil> Commit fixes 9b9c8195f3f0 ("tty: n_gsm: fix UAF in
 carnil> gsm_cleanup_mux") and aa371e96f05d ("tty: n_gsm: fix restart
 carnil> handling via CLD command") where the later was in 5.18-rc5 (and
 carnil> backported to 5.10.114 as well).
Bugs:
upstream: released (6.5-rc7) [3c4f8333b582487a2d1e02171f1465531cde53e3]
6.1-upstream-stable: released (6.1.47) [31311a9a4baae0ad47c85e448af21b2120344ff0]
5.10-upstream-stable: released (5.10.192) [869ce5e5984595bd2c62b598d977debc218b6f4d]
4.19-upstream-stable: N/A "Vulnerable code not present"
sid: released (6.4.13-1)
6.1-bookworm-security: released (6.1.52-1)
5.10-bullseye-security: released (5.10.197-1)
4.19-buster-security: N/A "Vulnerable code not present"