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s390/zcrypt: fix zcard and zqueue hot-unplug memleak

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commit 70fac8088c upstream.

Tests with kvm and a kmemdebug kernel showed, that on hot unplug the
zcard and zqueue structs for the unplugged card or queue are not
properly freed because of a mismatch with get/put for the embedded
kref counter.

This fix now adjusts the handling of the kref counters. With init the
kref counter starts with 1. This initial value needs to drop to zero
with the unregister of the card or queue to trigger the release and
free the object.

Fixes: 29c2680fd2 ("s390/ap: fix ap devices reference counting")
Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Cc: stable@vger.kernel.org
Reviewed-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Harald Freudenberger 2021-04-15 11:22:03 +02:00 • committed by Greg Kroah-Hartman
commit 026499a9c2
2 changed files with 2 additions and 0 deletions
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1
drivers/s390/crypto/zcrypt_card.c
View file

@ -192,5 +192,6 @@ void zcrypt_card_unregister(struct zcrypt_card *zc)
spin_unlock(&zcrypt_list_lock);
sysfs_remove_group(&zc->card->ap_dev.device.kobj,
&zcrypt_card_attr_group);
zcrypt_card_put(zc);
}
EXPORT_SYMBOL(zcrypt_card_unregister);

1
drivers/s390/crypto/zcrypt_queue.c
View file

@ -223,5 +223,6 @@ void zcrypt_queue_unregister(struct zcrypt_queue *zq)
sysfs_remove_group(&zq->queue->ap_dev.device.kobj,
&zcrypt_queue_attr_group);
zcrypt_card_put(zc);
zcrypt_queue_put(zq);
}
EXPORT_SYMBOL(zcrypt_queue_unregister);