mm: cma: Don't crash on allocation if CMA area can't be activated

commit f022d8cb7ec70fe8edd56383d876001317ee76b1 upstream.

If activation of the CMA area fails its mutex won't be initialized,
leading to an oops at allocation time when trying to lock the mutex. Fix
this by setting the cma area count field to 0 when activation fails,
leading to allocation returning NULL immediately.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/mm/cma.c b/mm/cma.c
index 0ab564623ea8..2904f45beab7 100644
--- a/mm/cma.c
+++ b/mm/cma.c
@@ -123,6 +123,7 @@ static int __init cma_activate_area(struct cma *cma)
 
 err:
 	kfree(cma->bitmap);
+	cma->count = 0;
 	return -EINVAL;
 }