Patch "arm64: dma-mapping: always clear allocated buffers" has been added to the 3.14-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    arm64: dma-mapping: always clear allocated buffers

to the 3.14-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:
     arm64-dma-mapping-always-clear-allocated-buffers.patch
and it can be found in the queue-3.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 6829e274a623187c24f7cfc0e3d35f25d087fcc5 Mon Sep 17 00:00:00 2001
From: Marek Szyprowski <m.szyprowski@samsung.com>
Date: Thu, 23 Apr 2015 12:46:16 +0100
Subject: arm64: dma-mapping: always clear allocated buffers

From: Marek Szyprowski <m.szyprowski@samsung.com>

commit 6829e274a623187c24f7cfc0e3d35f25d087fcc5 upstream.

Buffers allocated by dma_alloc_coherent() are always zeroed on Alpha,
ARM (32bit), MIPS, PowerPC, x86/x86_64 and probably other architectures.
It turned out that some drivers rely on this 'feature'. Allocated buffer
might be also exposed to userspace with dma_mmap() call, so clearing it
is desired from security point of view to avoid exposing random memory
to userspace. This patch unifies dma_alloc_coherent() behavior on ARM64
architecture with other implementations by unconditionally zeroing
allocated buffer.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
[will: ported to 3.14.y]
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/arm64/mm/dma-mapping.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -54,8 +54,7 @@ static void *arm64_swiotlb_alloc_coheren
 
 		*dma_handle = phys_to_dma(dev, page_to_phys(page));
 		addr = page_address(page);
-		if (flags & __GFP_ZERO)
-			memset(addr, 0, size);
+		memset(addr, 0, size);
 		return addr;
 	} else {
 		return swiotlb_alloc_coherent(dev, size, dma_handle, flags);


Patches currently in stable-queue which might be from m.szyprowski@samsung.com are

queue-3.14/arm64-dma-mapping-always-clear-allocated-buffers.patch