ipmi: kcs_bmc: handle devm_kasprintf() failure case

[ Upstream commit 42c7c6ef ]

devm_kasprintf() may return NULL if internal allocation failed so this
assignment is not safe. Moved the error exit path and added the !NULL
which then allows the devres manager to take care of cleanup.
Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Fixes: cd2315d4 ("ipmi: kcs_bmc: don't change device name")
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Reviewed-by: Haiyue Wang <haiyue.wang@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/char/ipmi/kcs_bmc.c

@@ -440,12 +440,13 @@ struct kcs_bmc *kcs_bmc_alloc(struct device *dev, int sizeof_priv, u32 channel)
 	kcs_bmc->data_in = devm_kmalloc(dev, KCS_MSG_BUFSIZ, GFP_KERNEL);
 	kcs_bmc->data_out = devm_kmalloc(dev, KCS_MSG_BUFSIZ, GFP_KERNEL);
 	kcs_bmc->kbuffer = devm_kmalloc(dev, KCS_MSG_BUFSIZ, GFP_KERNEL);
-	if (!kcs_bmc->data_in || !kcs_bmc->data_out || !kcs_bmc->kbuffer)
-		return NULL;
 
 	kcs_bmc->miscdev.minor = MISC_DYNAMIC_MINOR;
 	kcs_bmc->miscdev.name = devm_kasprintf(dev, GFP_KERNEL, "%s%u",
 					       DEVICE_NAME, channel);
+	if (!kcs_bmc->data_in || !kcs_bmc->data_out || !kcs_bmc->kbuffer ||
+	    !kcs_bmc->miscdev.name)
+		return NULL;
 	kcs_bmc->miscdev.fops = &kcs_bmc_fops;
 
 	return kcs_bmc;