Merge branch 'vsock-null-ptr-deref-when-so_linger-enabled'

Michal Luczaj says:

====================
vsock: null-ptr-deref when SO_LINGER enabled

syzbot pointed out that a recent patching of a use-after-free introduced a
null-ptr-deref. This series fixes the problem and adds a test.

v2: https://lore.kernel.org/20250206-vsock-linger-nullderef-v2-0-f8a1f19146f8@rbox.co
v1: https://lore.kernel.org/20250204-vsock-linger-nullderef-v1-0-6eb1760fa93e@rbox.co
====================

Link: https://patch.msgid.link/20250210-vsock-linger-nullderef-v3-0-ef6244d02b54@rbox.co
Signed-off-by: Jakub Kicinski <kuba@kernel.org>