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staging: vchiq_2835_arm: Fix NULL ptr dereference in free_pagelist

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commit 974d4d03fc020af4fa4e9e72a86f0fefa37803c5 upstream.

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: Stefan Wahren <stefan.wahren@i2se.com>
Fixes: 71bad7f08641 ("staging: add bcm2708 vchiq driver")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Stefan Wahren 2017-09-03 19:06:31 +02:00 committed by Greg Kroah-Hartman
parent 8928c5b2d3
commit 8a056a1152
1 changed files with 4 additions and 2 deletions
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6
drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c
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@ -538,18 +538,20 @@ free_pagelist(PAGELIST_T *pagelist, int actual)
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);