re: net: add a hardware buffer management helper API

re: net: add a hardware buffer management helper API

[Dan Carpenter]

Hello Gregory CLEMENT,

The patch 8cb2d8bf57e6: "net: add a hardware buffer management helper
API" from Mar 14, 2016, leads to the following static checker warning:

	net/core/hwbm.c:46 hwbm_pool_refill()
	warn: possible memory leak of 'buf'

net/core/hwbm.c
    26  /* Refill processing for HW buffer management */
    27  int hwbm_pool_refill(struct hwbm_pool *bm_pool, gfp_t gfp)
    28  {
    29          int frag_size = bm_pool->frag_size;
    30          void *buf;
    31  
    32          if (likely(frag_size <= PAGE_SIZE))
    33                  buf = netdev_alloc_frag(frag_size);
    34          else
    35                  buf = kmalloc(frag_size, gfp);
    36  
    37          if (!buf)
    38                  return -ENOMEM;
    39  
    40          if (bm_pool->construct)

If we don't have a ->construct() then we leak memory.  This test should
probably be moved to the start of the function or deleted.

    41                  if (bm_pool->construct(bm_pool, buf)) {
    42                          hwbm_buf_free(bm_pool, buf);
    43                          return -ENOMEM;
    44                  }
    45  
    46          return 0;
    47  }
    48  EXPORT_SYMBOL_GPL(hwbm_pool_refill);

regards,
dan carpenter

Re: net: add a hardware buffer management helper API

[Gregory CLEMENT]

Hi Dan,
 
 On mer., mars 16 2016, Dan Carpenter <dan.carpenter@oracle.com> wrote:

> Hello Gregory CLEMENT,
>
> The patch 8cb2d8bf57e6: "net: add a hardware buffer management helper
> API" from Mar 14, 2016, leads to the following static checker warning:
>
> 	net/core/hwbm.c:46 hwbm_pool_refill()
> 	warn: possible memory leak of 'buf'
>
> net/core/hwbm.c
>     26  /* Refill processing for HW buffer management */
>     27  int hwbm_pool_refill(struct hwbm_pool *bm_pool, gfp_t gfp)
>     28  {
>     29          int frag_size = bm_pool->frag_size;
>     30          void *buf;
>     31  
>     32          if (likely(frag_size <= PAGE_SIZE))
>     33                  buf = netdev_alloc_frag(frag_size);
>     34          else
>     35                  buf = kmalloc(frag_size, gfp);
>     36  
>     37          if (!buf)
>     38                  return -ENOMEM;
>     39  
>     40          if (bm_pool->construct)
>
> If we don't have a ->construct() then we leak memory.  This test should
> probably be moved to the start of the function or deleted.

I will prepare a patch to fix it.

Thanks,

Gregory

>
>     41                  if (bm_pool->construct(bm_pool, buf)) {
>     42                          hwbm_buf_free(bm_pool, buf);
>     43                          return -ENOMEM;
>     44                  }
>     45  
>     46          return 0;
>     47  }
>     48  EXPORT_SYMBOL_GPL(hwbm_pool_refill);
>
> regards,
> dan carpenter

-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com