On Thu, Jan 19, 2023 at 08:31:19AM +0000, Yuan Can wrote: > As the dma_alloc_coherent may return NULL, the return value needs to be > checked to avoid NULL poineter dereference. > > Fixes: 33aa8d45a4fe ("staging: emxx_udc: Add Emma Mobile USB Gadget driver") This really is not a "fix" as you will never hit this in real life. I'll drop that tag. > Signed-off-by: Yuan Can <yuancan@xxxxxxxxxx> > --- > changes in v2: > - do the null pointer check right before the memcpy(). > changes in v3: > - do the null pointer check right after the dma_alloc_coherent(). > > drivers/staging/emxx_udc/emxx_udc.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/staging/emxx_udc/emxx_udc.c b/drivers/staging/emxx_udc/emxx_udc.c > index b4e19174bef2..f9765841c4aa 100644 > --- a/drivers/staging/emxx_udc/emxx_udc.c > +++ b/drivers/staging/emxx_udc/emxx_udc.c > @@ -2587,10 +2587,15 @@ static int nbu2ss_ep_queue(struct usb_ep *_ep, > req->unaligned = false; > > if (req->unaligned) { > - if (!ep->virt_buf) > + if (!ep->virt_buf) { > ep->virt_buf = dma_alloc_coherent(udc->dev, PAGE_SIZE, > &ep->phys_buf, > GFP_ATOMIC | GFP_DMA); Wait, why is this asking for GFP_DMA memory? That's probably a different bug... thanks, greg k-h