From: Yue Hu huyue2@yulong.com
[ 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@gmail.com Signed-off-by: Yue Hu huyue2@yulong.com Reviewed-by: Andrew Morton akpm@linux-foundation.org Cc: Michal Hocko mhocko@suse.com Cc: Joe Perches joe@perches.com Cc: David Rientjes rientjes@google.com Cc: Dmitry Safonov d.safonov@partner.samsung.com Cc: Joonsoo Kim iamjoonsoo.kim@lge.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 275df8b5b22e7..c47ea3cfee791 100644 --- a/mm/cma_debug.c +++ b/mm/cma_debug.c @@ -58,7 +58,7 @@ 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);