Re: [PATCH] igb: check memory allocation failure

[Christophe JAILLET]

Le 28/08/2017 Ã 01:09, Waskiewicz Jr, Peter a ÃcritÂ:
> On 8/27/17 2:42 AM, Christophe JAILLET wrote:
> > Check memory allocation failures and return -ENOMEM in such cases, as
> > already done for other memory allocations in this function.
> >
> > This avoids NULL pointers dereference.
> >
> > Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
> > ---
> >    drivers/net/ethernet/intel/igb/igb_main.c | 2 ++
> >    1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
> > index fd4a46b03cc8..837d9b46a390 100644
> > --- a/drivers/net/ethernet/intel/igb/igb_main.c
> > +++ b/drivers/net/ethernet/intel/igb/igb_main.c
> > @@ -3162,6 +3162,8 @@ static int igb_sw_init(struct igb_adapter *adapter)
> >    	/* Setup and initialize a copy of the hw vlan table array */
> >    	adapter->shadow_vfta = kcalloc(E1000_VLAN_FILTER_TBL_SIZE, sizeof(u32),
> >    				       GFP_ATOMIC);
> > +	if (!adapter->shadow_vfta)
> > +		return -ENOMEM;
> Looks reasonable to me.
>
> A larger issue though I see in this function is that if we return
> -ENOMEM here, and if we return -ENOMEM from igb_init_interrupt_scheme()
> below on failure, we leak adapter->mac_table (and adapter->shadow_vfta
> in the latter).  We should add a proper unwind to free up the memory on
> failure.
>
> -PJ
Hi,

in fact, there is no leak because the only caller of 'igb_sw_init()' 
(i.e. 'igb_probe()'), already frees these resources in case of error, 
see [1]

These resources are also freed in 'igb_remove()'.

Best reagrds,
CJ

[1]: 
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/drivers/net/ethernet/intel/igb/igb_main.c#n2775