This is a note to let you know that I've just added the patch titled staging: vchiq_2835_arm: Fix NULL ptr dereference in free_pagelist to my staging git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git in the staging-linus branch. The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.) The patch will hopefully also be merged in Linus's tree for the next -rc kernel release. If you have any questions about this process, please let me know. >From 974d4d03fc020af4fa4e9e72a86f0fefa37803c5 Mon Sep 17 00:00:00 2001 From: Stefan Wahren <stefan.wahren@xxxxxxxx> Date: Sun, 3 Sep 2017 19:06:31 +0200 Subject: 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: Stefan Wahren <stefan.wahren@xxxxxxxx> Fixes: 71bad7f08641 ("staging: add bcm2708 vchiq driver") Cc: stable <stable@xxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c index 0159ca4407d8..be08849175ea 100644 --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c @@ -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); -- 2.14.1