Heuristic that checks if the memory pointer has been changed lacked a check
if the pointer was actually provided by the userspace, what allowed one to
queue a NULL pointer which was accepted without further checking. This
patch fixes this issue.
Reported-by: NSylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
CC: Pawel Osciak <pawel@osciak.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>