According to Christopher Lameter two fixes have been merged for the same
problem. As far as I can tell, the code does not acquire the list_lock and
invoke kmalloc().
list_slab_objects() misses an unlock (the counterpart to get_map()) and
the memory allocated in free_partial() isn't used.
Revert the mentioned commit.
Fixes: aa456c7aebb14 ("slub: remove kmalloc under list_lock from list_slab_objects() V2")
Link: https://lkml.kernel.org/r/alpine.DEB.2.22.394.2006181501480.12014@xxxxxxxxxxxxxxx
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
---
mm/slub.c | 19 ++++---------------
1 file changed, 4 insertions(+), 15 deletions(-)
diff --git a/mm/slub.c b/mm/slub.c
index b8f798b50d44d..72195cafbb503 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3766,15 +3766,13 @@ static int kmem_cache_open(struct kmem_cache *s, slab_flags_t flags)
}
static void list_slab_objects(struct kmem_cache *s, struct page *page,
- const char *text, unsigned long *map)
+ const char *text)
{
#ifdef CONFIG_SLUB_DEBUG
void *addr = page_address(page);
+ unsigned long *map;
void *p;
- if (!map)
- return;
-
slab_err(s, page, text, s->name);
slab_lock(page);
@@ -3786,6 +3784,7 @@ static void list_slab_objects(struct kmem_cache *s, struct page *page,
print_tracking(s, p);
}
}
+ put_map(map);
slab_unlock(page);
#endif
}
@@ -3799,11 +3798,6 @@ static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
{
LIST_HEAD(discard);
struct page *page, *h;
- unsigned long *map = NULL;
-
-#ifdef CONFIG_SLUB_DEBUG
- map = bitmap_alloc(oo_objects(s->max), GFP_KERNEL);
-#endif
BUG_ON(irqs_disabled());
spin_lock_irq(&n->list_lock);
@@ -3813,16 +3807,11 @@ static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
list_add(&page->slab_list, &discard);
} else {
list_slab_objects(s, page,
- "Objects remaining in %s on __kmem_cache_shutdown()",
- map);
+ "Objects remaining in %s on __kmem_cache_shutdown()");
}
}
spin_unlock_irq(&n->list_lock);
-#ifdef CONFIG_SLUB_DEBUG
- bitmap_free(map);
-#endif
-
list_for_each_entry_safe(page, h, &discard, slab_list)
discard_slab(s, page);
}
--
2.27.0
