Currently, an integer is used to specify the size in unmap_sg(). With 2GB worth of pages (512k 4k pages), it requires 31 bits (i.e. (1 << 19) << 12), which overflows the integer, and ends up unmapping more pages than intended. Subsequently, this results in IO_PAGE_FAULT.
Uses size_t instead of int to pass parameter to __unmap_single().
Please note that this patch is only for the stable-kernels tree because the commit be62dbf554c5 ("iommu/amd: Convert AMD iommu driver to the dma-iommu api"), which removes the function unmap_sg() was introduced in v5.5. This patch is not applicable in subsequent kernel versions.
Cc: stable@vger.kernel.org Cc: iommu@lists.linux-foundation.org Reported-by: Robert Lippert rlippert@google.com Signed-off-by: Suravee Suthikulpanit suravee.suthikulpanit@amd.com ---
drivers/iommu/amd_iommu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c index 32de8e7bb8b4..7adc021932b8 100644 --- a/drivers/iommu/amd_iommu.c +++ b/drivers/iommu/amd_iommu.c @@ -2670,7 +2670,7 @@ static void unmap_sg(struct device *dev, struct scatterlist *sglist, struct protection_domain *domain; struct dma_ops_domain *dma_dom; unsigned long startaddr; - int npages; + size_t npages;
domain = get_domain(dev); if (IS_ERR(domain))
On Wed, Jun 24, 2020 at 08:41:21AM +0000, Suravee Suthikulpanit wrote:
Currently, an integer is used to specify the size in unmap_sg(). With 2GB worth of pages (512k 4k pages), it requires 31 bits (i.e. (1 << 19) << 12), which overflows the integer, and ends up unmapping more pages than intended. Subsequently, this results in IO_PAGE_FAULT.
Uses size_t instead of int to pass parameter to __unmap_single().
Please note that this patch is only for the stable-kernels tree because the commit be62dbf554c5 ("iommu/amd: Convert AMD iommu driver to the dma-iommu api"), which removes the function unmap_sg() was introduced in v5.5. This patch is not applicable in subsequent kernel versions.
So what exact stable kernel version(s) do you want to see this patch applied to?
thanks,
greg k-h
On Wed, Jun 24, 2020 at 01:58:27PM +0200, Joerg Roedel wrote:
Hi Greg,
On Wed, Jun 24, 2020 at 11:09:06AM +0200, Greg KH wrote:
So what exact stable kernel version(s) do you want to see this patch applied to?
It is needed in kernels <= v5.4. Linux v5.5 has replaced the code with the bug.
This doesn't apply to any older kernels that I can see :(
On Wed, Jun 24, 2020 at 08:41:21AM +0000, Suravee Suthikulpanit wrote:
Currently, an integer is used to specify the size in unmap_sg(). With 2GB worth of pages (512k 4k pages), it requires 31 bits (i.e. (1 << 19) << 12), which overflows the integer, and ends up unmapping more pages than intended. Subsequently, this results in IO_PAGE_FAULT.
Uses size_t instead of int to pass parameter to __unmap_single().
Please note that this patch is only for the stable-kernels tree because the commit be62dbf554c5 ("iommu/amd: Convert AMD iommu driver to the dma-iommu api"), which removes the function unmap_sg() was introduced in v5.5. This patch is not applicable in subsequent kernel versions.
Cc: stable@vger.kernel.org Cc: iommu@lists.linux-foundation.org Reported-by: Robert Lippert rlippert@google.com Signed-off-by: Suravee Suthikulpanit suravee.suthikulpanit@amd.com
Acked-by: Joerg Roedel jroedel@suse.de
linux-stable-mirror@lists.linaro.org
-
Greg KH -
Joerg Roedel -
Suravee Suthikulpanit