[6.2][regression] after commit ffcb754584603adf7039d7972564fbf6febdc542 all sound devices disappeared (due BUG at mm/page_alloc.c:3592!)

[Christoph Hellwig]

On Fri, Dec 16, 2022 at 11:40:57AM +0000, Robin Murphy wrote:
> On 2022-12-16 06:46, Christoph Hellwig wrote:
>> Ok, it seems like the sound noncontig alloc code that I already
>> commented on as potentially bogus GFP_GOMP mapping trips this.  I think
>> for now the right thing would be to revert the hunk in dma-iommu.c
>> (see patch below).  The other thing to try would be to remove both
>> uses GFP_COMP in sound/core/memalloc.c, which should have the same
>> effect.
>
> Or we explicitly strip the flag in dma_alloc_noncontiguous() (and maybe 
> dma_alloc_pages() as well) for consistency with dma_alloc_attrs(). That 
> seems like it might be the most robust option.

In the long run warning there and returning an error seems like the
right thing to do, yes. I'm just a little worried doing this right now
after the merge window.