mm/cma.c: fix crash on CMA allocation if bitmap allocation fails

f022d8cb7ec7 ("mm: cma: Don't crash on allocation if CMA area can't be
activated") fixes the crash issue when activation fails via setting
cma->count as 0, same logic exists if bitmap allocation fails.

Link: http://lkml.kernel.org/r/20190325081309.6004-1-zbestahu@gmail.com
Signed-off-by: Yue Hu <huyue2@yulong.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/mm/cma.c b/mm/cma.c
index d72a02fb7759..5e36d7418031 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -106,8 +106,10 @@ static int __init cma_activate_area(struct cma *cma)
 
         cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
 
-        if (!cma->bitmap)
+        if (!cma->bitmap) {
+                cma->count = 0;
                 return -ENOMEM;
+        }
 
         WARN_ON_ONCE(!pfn_valid(pfn));
         zone = page_zone(pfn_to_page(pfn));