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slub: cure list_slab_objects() from double fix

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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.

Link: http://lkml.kernel.org/r/20200618201234.795692-1-bigeasy@linutronix.de
Fixes: aa456c7aeb ("slub: remove kmalloc under list_lock from list_slab_objects() V2")
Link: https://lkml.kernel.org/r/alpine.DEB.2.22.394.2006181501480.12014@www.lameter.com
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Sebastian Andrzej Siewior 2020-06-25 20:29:55 -07:00 committed by Linus Torvalds
parent 8982ae527f
commit 55860d96ca
1 changed files with 4 additions and 15 deletions
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19
mm/slub.c
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@ -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);
}