From: Miroslav Franc <mfranc@suse.cz>
Date: Thu, 11 Jan 2024 15:42:25 +0100
Subject: [PATCH] s390/dasd: fix double module refcount decrement
Git-commit: c3116e62ddeff79cae342147753ce596f01fcf06
Patch-Mainline: v6.9-rc1
References: bsc#1141539 git-fixes CVE-2024-27054 bsc#1223819

Once the discipline is associated with the device, deleting the device
takes care of decrementing the module's refcount.  Doing it manually on
this error path causes refcount to artificially decrease on each error
while it should just stay the same.

Link: https://lore.kernel.org/linux-s390/87le8vyl7l.fsf@/

Fixes: c020d722b110 ("s390/dasd: fix panic during offline processing")
Signed-off-by: Miroslav Franc <mfranc@suse.cz>
---
 drivers/s390/block/dasd.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 833cfab7d877..8e453454c271 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -3533,12 +3533,11 @@ int dasd_generic_set_online(struct ccw_device *cdev,
 		dasd_delete_device(device);
 		return -EINVAL;
 	}
+	device->base_discipline = base_discipline;
 	if (!try_module_get(discipline->owner)) {
-		module_put(base_discipline->owner);
 		dasd_delete_device(device);
 		return -EINVAL;
 	}
-	device->base_discipline = base_discipline;
 	device->discipline = discipline;
 
 	/* check_device will allocate block device if necessary */
@@ -3546,8 +3545,6 @@ int dasd_generic_set_online(struct ccw_device *cdev,
 	if (rc) {
 		pr_warn("%s Setting the DASD online with discipline %s failed with rc=%i\n",
 			dev_name(&cdev->dev), discipline->name, rc);
-		module_put(discipline->owner);
-		module_put(base_discipline->owner);
 		dasd_delete_device(device);
 		return rc;
 	}