Messages in this thread | | | Date | Wed, 24 Apr 2019 16:27:43 +0200 | From | Christoph Hellwig <> | Subject | Re: [PATCH] dma-mapping: remove an unnecessary NULL check |
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On Wed, Apr 24, 2019 at 05:24:37PM +0300, Dan Carpenter wrote: > We already dereferenced "dev" when we called get_dma_ops() so this NULL > check is too late. We're not supposed to pass NULL "dev" pointers to > dma_alloc_attrs().
Thanks, applied to the dma-mapping for-next tree.
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> > --- > There are still at least two drivers which do pass a NULL unfortunately. > > drivers/staging/comedi/drivers/comedi_isadma.c:195 comedi_isadma_alloc() error: NULL dereference inside function 'dma_alloc_coherent()' > drivers/staging/comedi/drivers/comedi_isadma.c:227 comedi_isadma_free() error: NULL dereference inside function 'dma_free_coherent()'
This is staging code. Per official decree from Linus we can just ignore it, and I tend to do so to keep my sanity.
> drivers/tty/synclink.c:3667 mgsl_alloc_buffer_list_memory() error: NULL dereference inside function 'dma_alloc_coherent()' > drivers/tty/synclink.c:3738 mgsl_free_buffer_list_memory() error: NULL dereference inside function 'dma_free_coherent()' > drivers/tty/synclink.c:3777 mgsl_alloc_frame_memory() error: NULL dereference inside function 'dma_alloc_coherent()' > drivers/tty/synclink.c:3811 mgsl_free_frame_memory() error: NULL dereference inside function 'dma_free_coherent()'
The !PCI case there is dead since I removed PCI support a while ago. Looks like it is still too convoluted for static checkers to notice that, though.
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