[PATCH v2 4/4] mm: lock slub page when listing objects

[Yu Zhao]

Though I have no idea what the side effect of such race would be,
apparently we want to prevent the free list from being changed
while debugging the objects.

Signed-off-by: Yu Zhao <yuz...@google.com>
---
 mm/slub.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/mm/slub.c b/mm/slub.c
index baa60dd73942..1c9726c28f0b 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -4608,11 +4608,15 @@ static void process_slab(struct loc_track *t, struct 
kmem_cache *s,
        void *p;
        unsigned long *map;
 
+       slab_lock(page);
+
        map = get_map(s, page);
        for_each_object(p, s, addr, page->objects)
                if (!test_bit(slab_index(p, s, addr), map))
                        add_location(t, s, get_track(s, p, alloc));
        put_map(map);
+
+       slab_unlock(page);
 }
 
 static int list_locations(struct kmem_cache *s, char *buf,
-- 
2.23.0.162.g0b9fbb3734-goog