CVE-2026-80984 net/smc: do not dereference an unset send buffer on the SMC-D teardown path

In the Linux kernel, the following vulnerability has been resolved: net/smc: do not dereference an unset send buffer on the SMC-D teardown path smcclosestreamwait calls smctxpreparedsends from inside its skwaitevent condition, and skwaitevent evaluates that condition once with the socket lock...