CVE-2026-80983

In the Linux kernel, the following vulnerability has been resolved:

net/smc: fix socket refcount leak in smc switch conns()

smc switch conns() takes a reference on the SMC socket before dropping lgr->conns lock, so the connection stays alive while the CDC slot is fetched:

sock hold(&smc->sk);
read unlock bh(&lgr->conns lock);
/* pre-fetch buffer outside of send lock, might sleep */
rc = smc cdc get free slot(conn, to lnk, &wr buf, NULL, &pend);
if (rc)
    goto err out;

The err out label only drops the wr tx link reference, so this early exit returns without the matching sock put(). The second error exit is not affected, because sock put() has already run by then.

A leaked sk refcnt means the smc sock is never destroyed. Its send and receive buffers stay allocated, and for a user socket the reference held on the network namespace is never released, so the netns can no longer be torn down.

smc cdc get free slot() fails when the target link goes down or when the connection has been killed while the switch is in progress. Both are reachable during the link failover this function implements, so the leak is triggered by the same hardware events that make smc switch conns() run in the first place.

Restructure so there is a single sock put() covering both outcomes, instead of adding a second one to the error path.