[PATCH 4.9 42/84] mm/memblock.c: reversed logic in memblock_discard()

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>

commit 91b540f98872a206ea1c49e4aa6ea8eed0886644 upstream.

In recently introduced memblock_discard() there is a reversed logic bug.
Memory is freed of static array instead of dynamically allocated one.

Link: http://lkml.kernel.org/r/1503511441-95478-2-git-send-email-pasha.tatashin@xxxxxxxxxx
Fixes: 3010f876500f ("mm: discard memblock data later")
Signed-off-by: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Reported-by: Woody Suwalski <terraluna977@xxxxxxxxx>
Tested-by: Woody Suwalski <terraluna977@xxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 mm/memblock.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -311,7 +311,7 @@ void __init memblock_discard(void)
 		__memblock_free_late(addr, size);
 	}
 
-	if (memblock.memory.regions == memblock_memory_init_regions) {
+	if (memblock.memory.regions != memblock_memory_init_regions) {
 		addr = __pa(memblock.memory.regions);
 		size = PAGE_ALIGN(sizeof(struct memblock_region) *
 				  memblock.memory.max);