slub: cure list_slab_objects() from double fix (55860d96) · Commits · 戴 / test

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: ("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>

mm/slub.c

+4 −15

Original line number	Diff line number	Diff line
		@@ -3766,15 +3766,13 @@ error:
		}

		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);
		}

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