> -----Original Message-----
> From: dmaengine-owner@xxxxxxxxxxxxxxx <dmaengine-
> owner@xxxxxxxxxxxxxxx> On Behalf Of Alexander.Barabash@xxxxxxxx
> Sent: Wednesday, December 25, 2019 10:56 AM
> To: dmaengine@xxxxxxxxxxxxxxx
> Cc: alexander.barabash@xxxxxxxxx
> Subject: [PATCH v2] ioat: ioat_alloc_ring() failure handling.
>
> If dma_alloc_coherent() returns NULL in ioat_alloc_ring(), ring allocation
> must not proceed.
>
> Until now, if the first call to dma_alloc_coherent() in
> ioat_alloc_ring() returned NULL, the processing could proceed, failing with
> NULL-pointer dereferencing further down the line.
>
> Signed-off-by: Alexander Barabash <alexander.barabash@xxxxxxxx>
Acked-by: Dave Jiang <dave.jiang@xxxxxxxxx>
> ---
> drivers/dma/ioat/dma.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/dma/ioat/dma.c b/drivers/dma/ioat/dma.c index
> 1a422a8..18c011e 100644
> --- a/drivers/dma/ioat/dma.c
> +++ b/drivers/dma/ioat/dma.c
> @@ -377,10 +377,11 @@ struct ioat_ring_ent **
>
> descs->virt = dma_alloc_coherent(to_dev(ioat_chan),
> SZ_2M, &descs->hw, flags);
> - if (!descs->virt && (i > 0)) {
> + if (!descs->virt) {
> int idx;
>
> for (idx = 0; idx < i; idx++) {
> + descs = &ioat_chan->descs[idx];
> dma_free_coherent(to_dev(ioat_chan),
> SZ_2M,
> descs->virt, descs->hw);
> descs->virt = NULL;
> --
> 1.8.3.1
