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authorToke Høiland-Jørgensen <toke@redhat.com>2023-03-13 10:17:24 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2023-05-11 23:03:02 +0900
commit42ca037d0c3fc4f7bb2ae2b47b6ea9ef59065fab (patch)
treeff0fe1147143e3e867aefc01c6fc6d6427d15a1f /crypto
parentd9834abd8b24d1fe8092859e436fe1e0fd467c61 (diff)
downloadlinux-42ca037d0c3fc4f7bb2ae2b47b6ea9ef59065fab.tar.gz
crypto: api - Demote BUG_ON() in crypto_unregister_alg() to a WARN_ON()
commit a543ada7db729514ddd3ba4efa45f4c7b802ad85 upstream.

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/87r0tyq8ph.fsf@toke.dk
Cc: stable@vger.kernel.org
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'crypto')
-rw-r--r--crypto/algapi.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/crypto/algapi.c b/crypto/algapi.c
index 5c69ff8e8fa5..c72622f20f52 100644
--- a/crypto/algapi.c
+++ b/crypto/algapi.c
@@ -472,7 +472,9 @@ void crypto_unregister_alg(struct crypto_alg *alg)
 	if (WARN(ret, "Algorithm %s is not registered", alg->cra_driver_name))
 		return;
 
-	BUG_ON(refcount_read(&alg->cra_refcnt) != 1);
+	if (WARN_ON(refcount_read(&alg->cra_refcnt) != 1))
+		return;
+
 	if (alg->cra_destroy)
 		alg->cra_destroy(alg);