4.7-stable review patch. If anyone has any objections, please let me know.
------------------ From: Jan Beulich <[email protected]> commit d4c4fed08f31f3746000c46cb1b20bed2959547a upstream. While commit 55f1ea15216 ("efi: Fix for_each_efi_memory_desc_in_map() for empty memmaps") made an attempt to deal with empty memory maps, it didn't address the case where the map field never gets set, as is apparently the case when running under Xen. Reported-by: <[email protected]> Tested-by: <[email protected]> Cc: Vitaly Kuznetsov <[email protected]> Cc: Jiri Slaby <[email protected]> Cc: Mark Rutland <[email protected]> Signed-off-by: Jan Beulich <[email protected]> [ Guard the loop with a NULL check instead of pointer underflow ] Signed-off-by: Matt Fleming <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- include/linux/efi.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -1005,7 +1005,7 @@ extern int efi_memattr_apply_permissions /* Iterate through an efi_memory_map */ #define for_each_efi_memory_desc_in_map(m, md) \ for ((md) = (m)->map; \ - ((void *)(md) + (m)->desc_size) <= (m)->map_end; \ + (md) && ((void *)(md) + (m)->desc_size) <= (m)->map_end; \ (md) = (void *)(md) + (m)->desc_size) /**
