crypto: api - Demote BUG_ON() in crypto_unregister_alg() to a WARN_ON()

The crypto_unregister_alg() function expects callers to ensure that any
algorithm that is unregistered has a refcnt of exactly 1, and issues a
BUG_ON() if this is not the case. However, there are in fact drivers that
will call crypto_unregister_alg() without ensuring that the refcnt has been
lowered first, most notably on system shutdown. This causes the BUG_ON() to
trigger, which prevents a clean shutdown and hangs the system.

To avoid such hangs on shutdown, demote the BUG_ON() in
crypto_unregister_alg() to a WARN_ON() with early return. Cc stable because
this problem was observed on a 6.2 kernel, cf the link below.

Link: https://lore.kernel.org/r/[email protected]
Cc: [email protected]
Signed-off-by: Toke Høiland-Jørgensen <[email protected]>
Signed-off-by: Herbert Xu <[email protected]>

0 files changed, 0 insertions, 0 deletions