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Commit 43a867a2 authored by Ralph Wuerthner's avatar Ralph Wuerthner Committed by Martin Schwidefsky
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[S390] zcrypt: fix possible race when unloading zcrypt driver modules 



Move try_module_get() call into spin protected block to prevent zcrypt
driver module unload while submitting a request to driver.

Signed-off-by: default avatarRalph Wuerthner <rwuerthn@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent cf352ce0

drivers/s390/crypto/zcrypt_api.c

+6 −6
Original line number Diff line number Diff line
@@ -298,14 +298,14 @@ static long zcrypt_rsa_modexpo(struct ica_rsa_modexpo *mex) 
		get_device(&zdev->ap_dev->device);

		zdev->request_count++;

		__zcrypt_decrease_preference(zdev);

		spin_unlock_bh(&zcrypt_device_lock);

		if (try_module_get(zdev->ap_dev->drv->driver.owner)) {

			spin_unlock_bh(&zcrypt_device_lock);

			rc = zdev->ops->rsa_modexpo(zdev, mex);

			spin_lock_bh(&zcrypt_device_lock);

			module_put(zdev->ap_dev->drv->driver.owner);

		}

		else

			rc = -EAGAIN;

		spin_lock_bh(&zcrypt_device_lock);

		zdev->request_count--;

		__zcrypt_increase_preference(zdev);

		put_device(&zdev->ap_dev->device);
@@ -373,14 +373,14 @@ static long zcrypt_rsa_crt(struct ica_rsa_modexpo_crt *crt) 
		get_device(&zdev->ap_dev->device);

		zdev->request_count++;

		__zcrypt_decrease_preference(zdev);

		spin_unlock_bh(&zcrypt_device_lock);

		if (try_module_get(zdev->ap_dev->drv->driver.owner)) {

			spin_unlock_bh(&zcrypt_device_lock);

			rc = zdev->ops->rsa_modexpo_crt(zdev, crt);

			spin_lock_bh(&zcrypt_device_lock);

			module_put(zdev->ap_dev->drv->driver.owner);

		}

		else

			rc = -EAGAIN;

		spin_lock_bh(&zcrypt_device_lock);

		zdev->request_count--;

		__zcrypt_increase_preference(zdev);

		put_device(&zdev->ap_dev->device);
@@ -408,14 +408,14 @@ static long zcrypt_send_cprb(struct ica_xcRB *xcRB) 
		get_device(&zdev->ap_dev->device);

		zdev->request_count++;

		__zcrypt_decrease_preference(zdev);

		spin_unlock_bh(&zcrypt_device_lock);

		if (try_module_get(zdev->ap_dev->drv->driver.owner)) {

			spin_unlock_bh(&zcrypt_device_lock);

			rc = zdev->ops->send_cprb(zdev, xcRB);

			spin_lock_bh(&zcrypt_device_lock);

			module_put(zdev->ap_dev->drv->driver.owner);

		}

		else

			rc = -EAGAIN;

		spin_lock_bh(&zcrypt_device_lock);

		zdev->request_count--;

		__zcrypt_increase_preference(zdev);

		put_device(&zdev->ap_dev->device);