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Commit 974d4d03 authored by Stefan Wahren's avatar Stefan Wahren Committed by Greg Kroah-Hartman
Browse files

staging: vchiq_2835_arm: Fix NULL ptr dereference in free_pagelist 



This fixes a NULL pointer dereference on RPi 2 with multi_v7_defconfig.
The function page_address() could return NULL with enabled CONFIG_HIGHMEM.
So fix this by using kmap() instead.

Signed-off-by: default avatarStefan Wahren <stefan.wahren@i2se.com>
Fixes: 71bad7f0 ("staging: add bcm2708 vchiq driver")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent e5f5d0e2

drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c

+4 −2
Original line number Diff line number Diff line
@@ -612,18 +612,20 @@ free_pagelist(struct vchiq_pagelist_info *pagelistinfo, 
			if (head_bytes > actual)

				head_bytes = actual;



			memcpy((char *)page_address(pages[0]) +

			memcpy((char *)kmap(pages[0]) +

				pagelist->offset,

				fragments,

				head_bytes);

			kunmap(pages[0]);

		}

		if ((actual >= 0) && (head_bytes < actual) &&

			(tail_bytes != 0)) {

			memcpy((char *)page_address(pages[num_pages - 1]) +

			memcpy((char *)kmap(pages[num_pages - 1]) +

				((pagelist->offset + actual) &

				(PAGE_SIZE - 1) & ~(g_cache_line_size - 1)),

				fragments + g_cache_line_size,

				tail_bytes);

			kunmap(pages[num_pages - 1]);

		}



		down(&g_free_fragments_mutex);