Re: [PATCH 1/1] swiotlb: fix out-of-bounds TLB allocations with CONFIG_SWIOTLB_DYNAMIC

[Niklas Schnelle]

On Wed, 2023-11-08 at 13:21 +0100, Petr Tesařík wrote:
> On Wed,  8 Nov 2023 12:12:49 +0100
> Petr Tesarik <petrtesarik@xxxxxxxxxxxxxxx> wrote:
> 
> > From: Petr Tesarik <petr.tesarik1@xxxxxxxxxxxxxxxxxxx>
> > 
> > Limit the free list length to the size of the IO TLB. Transient pool can be
> > smaller than IO_TLB_SEGSIZE, but the free list is initialized with the
> > assumption that the total number of slots is a multiple of IO_TLB_SEGSIZE.
> > As a result, swiotlb_area_find_slots() may allocate slots past the end of
> > a transient IO TLB buffer.
> 
> Just to make it clear, this patch addresses only the memory corruption
> reported by Niklas, without addressing the underlying issues. Where
> corruption happened before, allocations will fail with this patch.
> 
> I am still looking into improving the allocation strategy itself.
> 
> Petr T

I know this has already been applied but for what its worth I did
finally manage to test this with my reproducer and the allocation
overrun is fixed by this change. I also confirmed that at least my
ConnectX VF TCP/IP test case seems to handle the DMA error gracefully
enough.

Thanks,
Niklas