On Wed, 8 Nov 2023 12:12:49 +0100 Petr Tesarik petrtesarik@huaweicloud.com wrote:
From: Petr Tesarik petr.tesarik1@huawei-partners.com
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@linux.ibm.com Closes: https://lore.kernel.org/linux-iommu/104a8c8fedffd1ff8a2890983e2ec1c26bff6810... Fixes: 79636caad361 ("swiotlb: if swiotlb is full, fall back to a transient memory pool") Cc: Halil Pasic pasic@linux.ibm.com Cc: stable@vger.kernel.org Signed-off-by: Petr Tesarik petr.tesarik1@huawei-partners.com
Reviewed-by: Halil Pasic pasic@linux.ibm.com
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