Commit 835832ba authored by Jianqun Xu's avatar Jianqun Xu Committed by Linus Torvalds
Browse files

mm/cma.c: fix NULL pointer dereference when cma could not be activated 



In some case the cma area could not be activated, but the cma_alloc be
used under this case, then the kernel will crash caused by NULL pointer
dereference.

Add bitmap valid check in cma_alloc to avoid this issue.

Signed-off-by: default avatarJianqun Xu <jay.xu@rock-chips.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
Link: http://lkml.kernel.org/r/20200615010123.15596-1-jay.xu@rock-chips.com


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 1a5bae25

mm/cma.c

+1 −1
Original line number Diff line number Diff line
@@ -425,7 +425,7 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align, 
	struct page *page = NULL;

	int ret = -ENOMEM;



	if (!cma || !cma->count)

	if (!cma || !cma->count || !cma->bitmap)

		return NULL;



	pr_debug("%s(cma %p, count %zu, align %d)\n", __func__, (void *)cma,