On Mon, 25 Jun 2018, Greg Kroah-Hartman wrote:

On Thu, Jun 14, 2018 at 09:29:11PM +0800, Zhouyang Jia wrote:

quoted

When kcalloc fails, the lack of error-handling code may
cause unexpected results.

This patch adds error-handling code after calling kcalloc.

Signed-off-by: Zhouyang Jia <redacted>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
---
v1->v2:
- Remove pr_warn statement.
---
 drivers/usb/storage/alauda.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/usb/storage/alauda.c b/drivers/usb/storage/alauda.c
index 900591d..4e17609 100644
--- a/drivers/usb/storage/alauda.c
+++ b/drivers/usb/storage/alauda.c

@@ -437,6 +437,9 @@ static int alauda_init_media(struct us_data *us)
 		+ MEDIA_INFO(us).blockshift + MEDIA_INFO(us).pageshift);
 	MEDIA_INFO(us).pba_to_lba = kcalloc(num_zones, sizeof(u16*), GFP_NOIO);
 	MEDIA_INFO(us).lba_to_pba = kcalloc(num_zones, sizeof(u16*), GFP_NOIO);
+	if ((MEDIA_INFO(us).pba_to_lba == NULL)
+		|| (MEDIA_INFO(us).lba_to_pba == NULL))
+		return USB_STOR_TRANSPORT_ERROR;

You just leaked memory if only one of these succeeded :(

That's not really true.  The memory gets deallocated later on in any 
case, when alauda_info_destructor() calls alauda_free_maps() if not 
before.

More troubling is the fact that this routine (i.e, alauda_init_media)  
gets called from only one place, in alauda_check_media, and the caller
completely ignores the return value!  Furthermore, the caller always
returns USB_STOR_TRANSPORT_FAILED.

So on the whole, I don't think this patch is going to make any 
difference to the driver's operation.

Alan Stern
---
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