[PATCH] drivers: dma-coherent: free memory when failed to init DMA memory pool

[Duan Andy]

From: Mike Nazarewicz <mpn at google.com> Sent: Thursday, December 03, 2015 8:51 PM
> To: Duan Fugang-B38611; torvalds at linux-foundation.org;
> gregkh at linuxfoundation.org; m.szyprowski at samsung.com
> Cc: linux-arm-kernel at lists.infradead.org; arnd at arndb.de;
> iamjoonsoo.kim at lge.com; Duan Fugang-B38611
> Subject: Re: [PATCH] drivers: dma-coherent: free memory when failed to
> init DMA memory pool
> 
> On Thu, Dec 03 2015, Fugang Duan wrote:
> > Free dma coherent memory when it failed to init DMA memory pool after
> > calling .dma_init_coherent_memory(), otherwise it causes memmory leak.
> >
> > Signed-off-by: Fugang Duan <B38611 at freescale.com>
> > ---
> >  drivers/base/dma-coherent.c | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/base/dma-coherent.c b/drivers/base/dma-coherent.c
> > index 55b8398..beb6bbe 100644
> > --- a/drivers/base/dma-coherent.c
> > +++ b/drivers/base/dma-coherent.c
> > @@ -286,6 +286,7 @@ static int rmem_dma_device_init(struct reserved_mem
> *rmem, struct device *dev)
> >  				     &mem) != DMA_MEMORY_MAP) {
> >  		pr_err("Reserved memory: failed to init DMA memory pool
> at %pa, size %ld MiB\n",
> >  			&rmem->base, (unsigned long)rmem->size / SZ_1M);
> > +		kfree(mem);
> 
> mem == NULL at this point.  If dma_init_coherent_memory doesn’t return
> DMA_MEMORY_MAP, mem pointer is not assigned any value.  If you think
> there is a memory leak, please demonstrate a path of it happening.
> 
Kfree() will check mem NULL condition, so no need to add check in here.


> >  		return -ENODEV;
> >  	}
> >  	rmem->priv = mem;
> > --
> > 1.9.1
> >
> 
> --
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