[PATCH 6.2 069/663] crypto: api - Demote BUG_ON() in crypto_unregister_alg() to a WARN_ON()

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



From: Toke Høiland-Jørgensen <toke@xxxxxxxxxx>

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@xxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Toke Høiland-Jørgensen <toke@xxxxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 crypto/algapi.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/crypto/algapi.c
+++ b/crypto/algapi.c
@@ -493,7 +493,9 @@ void crypto_unregister_alg(struct crypto
 	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);
 





[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux