3.18-stable review patch. If anyone has any objections, please let me know.
------------------ From: Thierry Reding <[email protected]> commit 620951e2745750de1482128615adc15b74ee37ed upstream. kmemleak will add allocations as objects to a pool. The memory allocated for each object in this pool is periodically searched for pointers to other allocated objects. This only works for memory that is mapped into the kernel's virtual address space, which happens not to be the case for most CMA regions. Furthermore, CMA regions are typically used to store data transferred to or from a device and therefore don't contain pointers to other objects. Without this, the kernel crashes on the first execution of the scan_gray_list() because it tries to access highmem. Perhaps a more appropriate fix would be to reject any object that can't map to a kernel virtual address? [[email protected]: add comment] [[email protected]: fix comment, per Catalin] [[email protected]: include linux/io.h for phys_to_virt()] Signed-off-by: Thierry Reding <[email protected]> Cc: Michal Nazarewicz <[email protected]> Cc: Marek Szyprowski <[email protected]> Cc: Joonsoo Kim <[email protected]> Cc: "Aneesh Kumar K.V" <[email protected]> Cc: Catalin Marinas <[email protected]> Signed-off-by: Stephen Rothwell <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- mm/cma.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/mm/cma.c +++ b/mm/cma.c @@ -33,6 +33,7 @@ #include <linux/log2.h> #include <linux/cma.h> #include <linux/highmem.h> +#include <linux/io.h> struct cma { unsigned long base_pfn; @@ -325,6 +326,11 @@ int __init cma_declare_contiguous(phys_a } } + /* + * kmemleak scans/reads tracked objects for pointers to other + * objects but this address isn't mapped and accessible + */ + kmemleak_ignore(phys_to_virt(addr)); base = addr; }
