Re: [v2] cw1200: Don't leak memory if krealloc failes

[Kalle Valo]

Johannes Thumshirn  wrote:
> The call to krealloc() in wsm_buf_reserve() directly assigns the newly
> returned memory to buf->begin. This is all fine except when krealloc()
> failes we loose the ability to free the old memory pointed to by
> buf->begin. If we just create a temporary variable to assign memory to
> and assign the memory to it we can mitigate the memory leak.
> 
> Signed-off-by: Johannes Thumshirn 
> Cc: Johannes Berg 

Patch applied to wireless-drivers-next.git, thanks.

9afdd6128c39 cw1200: Don't leak memory if krealloc failes

-- 
https://patchwork.kernel.org/patch/9358185/

Documentation about submitting wireless patches and checking status
from patchwork:

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches

[PATCH v2] cw1200: Don't leak memory if krealloc failes

[Johannes Thumshirn]

The call to krealloc() in wsm_buf_reserve() directly assigns the newly
returned memory to buf->begin. This is all fine except when krealloc()
failes we loose the ability to free the old memory pointed to by
buf->begin. If we just create a temporary variable to assign memory to
and assign the memory to it we can mitigate the memory leak.

Signed-off-by: Johannes Thumshirn 
Cc: Johannes Berg 
---
 drivers/net/wireless/st/cw1200/wsm.c | 16 +---
 1 file changed, 9 insertions(+), 7 deletions(-)

Changes from v1:
* Do the correct check for a failed re-allocation (Johannes Berg)

diff --git a/drivers/net/wireless/st/cw1200/wsm.c 
b/drivers/net/wireless/st/cw1200/wsm.c
index 680d60e..ffb245e 100644
--- a/drivers/net/wireless/st/cw1200/wsm.c
+++ b/drivers/net/wireless/st/cw1200/wsm.c
@@ -1807,16 +1807,18 @@ static int wsm_buf_reserve(struct wsm_buf *buf, size_t 
extra_size)
 {
size_t pos = buf->data - buf->begin;
size_t size = pos + extra_size;
+   u8 *tmp;
 
size = round_up(size, FWLOAD_BLOCK_SIZE);
 
-   buf->begin = krealloc(buf->begin, size, GFP_KERNEL | GFP_DMA);
-   if (buf->begin) {
-   buf->data = >begin[pos];
-   buf->end = >begin[size];
-   return 0;
-   } else {
-   buf->end = buf->data = buf->begin;
+   tmp = krealloc(buf->begin, size, GFP_KERNEL | GFP_DMA);
+   if (!tmp) {
+   wsm_buf_deinit(buf);
return -ENOMEM;
}
+
+   buf->begin = tmp;
+   buf->data = >begin[pos];
+   buf->end = >begin[size];
+   return 0;
 }
-- 
1.8.5.6