This is a note to let you know that I've just added the patch titled s390/zcrypt: fix zcard and zqueue hot-unplug memleak to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: s390-zcrypt-fix-zcard-and-zqueue-hot-unplug-memleak.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 70fac8088cfad9f3b379c9082832b4d7532c16c2 Mon Sep 17 00:00:00 2001 From: Harald Freudenberger <freude@xxxxxxxxxxxxx> Date: Thu, 15 Apr 2021 11:22:03 +0200 Subject: s390/zcrypt: fix zcard and zqueue hot-unplug memleak From: Harald Freudenberger <freude@xxxxxxxxxxxxx> commit 70fac8088cfad9f3b379c9082832b4d7532c16c2 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: 29c2680fd2bf ("s390/ap: fix ap devices reference counting") Reported-by: Marc Hartmayer <mhartmay@xxxxxxxxxxxxx> Signed-off-by: Harald Freudenberger <freude@xxxxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Reviewed-by: Julian Wiedmann <jwi@xxxxxxxxxxxxx> Signed-off-by: Heiko Carstens <hca@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/s390/crypto/zcrypt_card.c | 1 + drivers/s390/crypto/zcrypt_queue.c | 1 + 2 files changed, 2 insertions(+) --- a/drivers/s390/crypto/zcrypt_card.c +++ b/drivers/s390/crypto/zcrypt_card.c @@ -192,5 +192,6 @@ void zcrypt_card_unregister(struct zcryp 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); --- a/drivers/s390/crypto/zcrypt_queue.c +++ b/drivers/s390/crypto/zcrypt_queue.c @@ -223,5 +223,6 @@ void zcrypt_queue_unregister(struct zcry 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); Patches currently in stable-queue which might be from freude@xxxxxxxxxxxxx are queue-5.10/s390-zcrypt-fix-zcard-and-zqueue-hot-unplug-memleak.patch