This is a note to let you know that I've just added the patch titled MIPS: vDSO: Fix Malta EVA mapping to vDSO page structs to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mips-vdso-fix-malta-eva-mapping-to-vdso-page-structs.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 554af0c396380baf416f54c439b99b495180b2f4 Mon Sep 17 00:00:00 2001 From: James Hogan <james.hogan@xxxxxxxxxx> Date: Wed, 7 Sep 2016 13:37:01 +0100 Subject: MIPS: vDSO: Fix Malta EVA mapping to vDSO page structs From: James Hogan <james.hogan@xxxxxxxxxx> commit 554af0c396380baf416f54c439b99b495180b2f4 upstream. The page structures associated with the vDSO pages in the kernel image are calculated using virt_to_page(), which uses __pa() under the hood to find the pfn associated with the virtual address. The vDSO data pointers however point to kernel symbols, so __pa_symbol() should really be used instead. Since there is no equivalent to virt_to_page() which uses __pa_symbol(), fix init_vdso_image() to work directly with pfns, calculated with __phys_to_pfn(__pa_symbol(...)). This issue broke the Malta Enhanced Virtual Addressing (EVA) configuration which has a non-default implementation of __pa_symbol(). This is because it uses a physical alias so that the kernel executes from KSeg0 (VA 0x80000000 -> PA 0x00000000), while RAM is provided to the kernel in the KUSeg range (VA 0x00000000 -> PA 0x80000000) which uses the same underlying RAM. Since there are no page structures associated with the low physical address region, some arbitrary kernel memory would be interpreted as a page structure for the vDSO pages and badness ensues. Fixes: ebb5e78cc634 ("MIPS: Initial implementation of a VDSO") Signed-off-by: James Hogan <james.hogan@xxxxxxxxxx> Cc: Leonid Yegoshin <leonid.yegoshin@xxxxxxxxxx> Cc: linux-mips@xxxxxxxxxxxxxx Patchwork: https://patchwork.linux-mips.org/patch/14229/ Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/mips/kernel/vdso.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/arch/mips/kernel/vdso.c +++ b/arch/mips/kernel/vdso.c @@ -39,16 +39,16 @@ static struct vm_special_mapping vdso_vv static void __init init_vdso_image(struct mips_vdso_image *image) { unsigned long num_pages, i; + unsigned long data_pfn; BUG_ON(!PAGE_ALIGNED(image->data)); BUG_ON(!PAGE_ALIGNED(image->size)); num_pages = image->size / PAGE_SIZE; - for (i = 0; i < num_pages; i++) { - image->mapping.pages[i] = - virt_to_page(image->data + (i * PAGE_SIZE)); - } + data_pfn = __phys_to_pfn(__pa_symbol(image->data)); + for (i = 0; i < num_pages; i++) + image->mapping.pages[i] = pfn_to_page(data_pfn + i); } static int __init init_vdso(void) Patches currently in stable-queue which might be from james.hogan@xxxxxxxxxx are queue-4.4/mips-vdso-fix-malta-eva-mapping-to-vdso-page-structs.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html