Description: mptcp: fix possible deadlock in subflow diag
References:
Notes:
 carnil> Introduced in b8adb69a7d29 ("mptcp: fix lockless access in subflow ULP diag").
 carnil> Vulnerable versions: 5.10.211 5.15.150 6.1.80 6.6.19 6.7.7 6.8-rc6.
Bugs:
upstream: released (6.8-rc7) [d6a9608af9a75d13243d217f6ce1e30e57d56ffe]
6.7-upstream-stable: released (6.7.9) [d487e7ba1bc7444d5f062c4930ef8436c47c7e63]
6.6-upstream-stable: released (6.6.21) [fa8c776f4c323a9fbc8ddf25edcb962083391430]
6.1-upstream-stable: released (6.1.81) [f27d319df055629480b84b9288a502337b6f2a2e]
5.10-upstream-stable: released (5.10.212) [70e5b013538d5e4cb421afed431a5fcd2a5d49ee]
4.19-upstream-stable: N/A "Vulnerable code not present"
sid: released (6.7.9-1)
6.1-bookworm-security: released (6.1.82-1)
5.10-bullseye-security: needed
4.19-buster-security: N/A "Vulnerable code not present"