Description: mptcp: fix double-free on socket dismantle
References:
Notes:
 carnil> Introduced in cf7da0d66cc1 ("mptcp: Create SUBFLOW socket for incoming
 carnil> connections"). Vulnerable versions: 5.6-rc1.
Bugs:
upstream: released (6.8-rc7) [10048689def7e40a4405acda16fdc6477d4ecc5c]
6.7-upstream-stable: released (6.7.9) [85933e80d077c9ae2227226beb86c22f464059cc]
6.6-upstream-stable: released (6.6.21) [ce0809ada38dca8d6d41bb57ab40494855c30582]
6.1-upstream-stable: released (6.1.81) [d93fd40c62397326046902a2c5cb75af50882a85]
5.10-upstream-stable: released (5.10.212) [f74362a004225df935863dea6eb7d82daaa5b16e]
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"