[ Upstream commit de8a6b15d9654c3e4f672d76da9d9df8ee06331d ] Currently, we correlate the mctp_sk_key lifetime to the sock lifetime through the sock hash/unhash operations, but this is pretty tenuous, and there are cases where we may have a temporary reference to an unhashed sk. This change makes the reference more explicit, by adding a hold on the sock when it's associated with a mctp_sk_key, released on final key unref. Fixes: 73c618456dc5 ("mctp: locking, lifetime and validity changes for sk_keys") Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>