[PATCH] ipmi: kcs_bmc: handle devm_kasprintf() failure case

[Nicholas Mc Guire]

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@xxxxxxxxx>
Fixes: cd2315d471f4 ("ipmi: kcs_bmc: don't change device name")
---

Problem located with experimental coccinelle script

Patch was compile tested with: aspeed_g5_defconfig (implies
CONFIG_IPMI_KCS_BMC=y)

Patch is against 4.20-rc3 (localversion-next is next-20181121)

 drivers/char/ipmi/kcs_bmc.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/char/ipmi/kcs_bmc.c b/drivers/char/ipmi/kcs_bmc.c
index e6124bd..86d29d2 100644
--- a/drivers/char/ipmi/kcs_bmc.c
+++ b/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;
-- 
2.1.4