[PATCH v2] s390: raw3270: Handle allocation failures

[PATCH v2] s390: raw3270: Handle allocation failures

[Triet Hoang]

Check the return values of kzalloc_obj() and kzalloc() before using the
allocated memory. Free the allocated resources on subsequent initialization
failures to avoid leaking memory.

Signed-off-by: Triet Hoang <triet.hoang.dev@gmail.com>
---
Changes in v2:
- Destroy the console device on allocation failure.
- Do not free rp after raw3270_setup_device() success.
---
 drivers/s390/char/raw3270.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/s390/char/raw3270.c b/drivers/s390/char/raw3270.c
index aa9c4d81225c..ff397396b440 100644
--- a/drivers/s390/char/raw3270.c
+++ b/drivers/s390/char/raw3270.c
@@ -814,10 +814,23 @@ struct raw3270 __init *raw3270_setup_console(void)
 		return ERR_CAST(cdev);
 
 	rp = kzalloc_obj(*rp, GFP_KERNEL | GFP_DMA);
+	if (!rp) {
+		ccw_device_destroy_console(cdev);
+		return ERR_PTR(-ENOMEM);
+	}
 	ascebc = kzalloc(256, GFP_KERNEL);
+	if (!ascebc) {
+		ccw_device_destroy_console(cdev);
+		kfree(rp);
+		return ERR_PTR(-ENOMEM);
+	}
 	rc = raw3270_setup_device(cdev, rp, ascebc);
-	if (rc)
+	if (rc) {
+		ccw_device_destroy_console(cdev);
+		kfree(rp->ascebc);
+		kfree(rp);
 		return ERR_PTR(rc);
+	}
 	set_bit(RAW3270_FLAGS_CONSOLE, &rp->flags);
 
 	rc = ccw_device_enable_console(cdev);
-- 
2.53.0

Re: [PATCH v2] s390: raw3270: Handle allocation failures

[Markus Elfring]

> Check the return values of kzalloc_obj() and kzalloc() before using the
> allocated memory. Free the allocated resources on subsequent initialization
> failures to avoid leaking memory.

* How do you think about to add any tags (like “Fixes” and “Cc”) accordingly?
  https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v7.2#n145
  https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/stable-kernel-rules.rst?h=v7.2#n34

* Please avoid duplicate source code also for an improved implementation of
  the function “raw3270_setup_console”.
  https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/coding-style.rst?h=v7.2#n526
  https://elixir.bootlin.com/linux/v7.2/source/drivers/s390/char/raw3270.c#L802-L839

* How do you think about to increase the application of scope-based resource management?


Regards,
Markus