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Commit 57db53b0 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'slab/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux 

* 'slab/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux:
  slub: avoid potential NULL dereference or corruption
  slub: use irqsafe_cpu_cmpxchg for put_cpu_partial
  slub: move discard_slab out of node lock
  slub: use correct parameter to add a page to partial list tail
parents 883381d9 bc6697d8

mm/slub.c

+26 −16
Original line number Diff line number Diff line
@@ -1862,7 +1862,7 @@ static void unfreeze_partials(struct kmem_cache *s) 
{

	struct kmem_cache_node *n = NULL;

	struct kmem_cache_cpu *c = this_cpu_ptr(s->cpu_slab);

	struct page *page;

	struct page *page, *discard_page = NULL;



	while ((page = c->partial)) {

		enum slab_modes { M_PARTIAL, M_FREE };
@@ -1904,7 +1904,8 @@ static void unfreeze_partials(struct kmem_cache *s) 
				if (l == M_PARTIAL)

					remove_partial(n, page);

				else

					add_partial(n, page, 1);

					add_partial(n, page,

						DEACTIVATE_TO_TAIL);



				l = m;

			}
@@ -1915,14 +1916,22 @@ static void unfreeze_partials(struct kmem_cache *s) 
				"unfreezing slab"));



		if (m == M_FREE) {

			stat(s, DEACTIVATE_EMPTY);

			discard_slab(s, page);

			stat(s, FREE_SLAB);

			page->next = discard_page;

			discard_page = page;

		}

	}



	if (n)

		spin_unlock(&n->list_lock);



	while (discard_page) {

		page = discard_page;

		discard_page = discard_page->next;



		stat(s, DEACTIVATE_EMPTY);

		discard_slab(s, page);

		stat(s, FREE_SLAB);

	}

}



/*
@@ -1969,7 +1978,7 @@ int put_cpu_partial(struct kmem_cache *s, struct page *page, int drain) 
		page->pobjects = pobjects;

		page->next = oldpage;



	} while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page) != oldpage);

	} while (irqsafe_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page) != oldpage);

	stat(s, CPU_PARTIAL_FREE);

	return pobjects;

}
@@ -4435,30 +4444,31 @@ static ssize_t show_slab_objects(struct kmem_cache *s, 


		for_each_possible_cpu(cpu) {

			struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);

			int node = ACCESS_ONCE(c->node);

			struct page *page;



			if (!c || c->node < 0)

			if (node < 0)

				continue;



			if (c->page) {

			page = ACCESS_ONCE(c->page);

			if (page) {

				if (flags & SO_TOTAL)

						x = c->page->objects;

					x = page->objects;

				else if (flags & SO_OBJECTS)

					x = c->page->inuse;

					x = page->inuse;

				else

					x = 1;



				total += x;

				nodes[c->node] += x;

				nodes[node] += x;

			}

			page = c->partial;



			if (page) {

				x = page->pobjects;

				total += x;

                                nodes[c->node] += x;

				nodes[node] += x;

			}

			per_cpu[c->node]++;

			per_cpu[node]++;

		}

	}