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. > > Reported-by: Niklas Schnelle <schnelle@xxxxxxxxxxxxx> > Closes: https://lore.kernel.org/linux-iommu/104a8c8fedffd1ff8a2890983e2ec1c26bff6810.camel@xxxxxxxxxxxxx/ > Fixes: 79636caad361 ("swiotlb: if swiotlb is full, fall back to a transient memory pool") > Cc: Halil Pasic <pasic@xxxxxxxxxxxxx> > Cc: stable@xxxxxxxxxxxxxxx > Signed-off-by: Petr Tesarik <petr.tesarik1@xxxxxxxxxxxxxxxxxxx> Reviewed-by: Halil Pasic <pasic@xxxxxxxxxxxxx> I believe there is at least one stale comment in the code that says "The number of slot in an area should be a multiple of IO_TLB_SEGSIZE" but that is probably not stable material, so I do agree with keeping this patch minimal. Regards, Halil
