From: Yue Hu <huyue2@xxxxxxxxxx> [ Upstream commit f0fd50504a54f5548eb666dc16ddf8394e44e4b7 ] If not find zero bit in find_next_zero_bit(), it will return the size parameter passed in, so the start bit should be compared with bitmap_maxno rather than cma->count. Although getting maxchunk is working fine due to zero value of order_per_bit currently, the operation will be stuck if order_per_bit is set as non-zero. Link: http://lkml.kernel.org/r/20190319092734.276-1-zbestahu@xxxxxxxxx Signed-off-by: Yue Hu <huyue2@xxxxxxxxxx> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Joe Perches <joe@xxxxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Cc: Dmitry Safonov <d.safonov@xxxxxxxxxxxxxxxxxxx> Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- mm/cma_debug.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/cma_debug.c b/mm/cma_debug.c index f8e4b60db1672..da50dab56b700 100644 --- a/mm/cma_debug.c +++ b/mm/cma_debug.c @@ -57,7 +57,7 @@ static int cma_maxchunk_get(void *data, u64 *val) mutex_lock(&cma->lock); for (;;) { start = find_next_zero_bit(cma->bitmap, bitmap_maxno, end); - if (start >= cma->count) + if (start >= bitmap_maxno) break; end = find_next_bit(cma->bitmap, bitmap_maxno, start); maxchunk = max(end - start, maxchunk); -- 2.20.1
