Merge branch 'vsock-fix-transport_-h2g-g2h-dgram-local-toctou-issues'

Michal Luczaj says:

====================
vsock: Fix transport_{h2g,g2h,dgram,local} TOCTOU issues

transport_{h2g,g2h,dgram,local} may become NULL on vsock_core_unregister().
Make sure a poorly timed `rmmod transport` won't lead to a NULL/stale
pointer dereference.

Note that these oopses are pretty unlikely to happen in the wild. Splats
were collected after sprinkling kernel with mdelay()s.

v3: https://lore.kernel.org/20250702-vsock-transports-toctou-v3-0-0a7e2e692987@rbox.co
v2: https://lore.kernel.org/20250620-vsock-transports-toctou-v2-0-02ebd20b1d03@rbox.co
v1: https://lore.kernel.org/20250618-vsock-transports-toctou-v1-0-dd2d2ede9052@rbox.co
====================

Link: https://patch.msgid.link/20250703-vsock-transports-toctou-v4-0-98f0eb530747@rbox.co


Signed-off-by: Jakub Kicinski <kuba@kernel.org>