forked from Minki/linux
0142eae3ae
In the SLAB allocator kmemcheck_slab_alloc() is guarded against being called in case the object is NULL. In SLUB allocator this NULL pointer invocation can happen, which seems like an oversight. Move the NULL pointer check into kmemcheck code (kmemcheck_slab_alloc) so the check gets moved out of the fastpath, when not compiled with CONFIG_KMEMCHECK. This is a step towards sharing post_alloc_hook between SLUB and SLAB, because slab_post_alloc_hook() does not perform this check before calling kmemcheck_slab_alloc(). Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
127 lines
2.9 KiB
C
127 lines
2.9 KiB
C
#include <linux/gfp.h>
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#include <linux/mm_types.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include "slab.h"
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#include <linux/kmemcheck.h>
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void kmemcheck_alloc_shadow(struct page *page, int order, gfp_t flags, int node)
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{
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struct page *shadow;
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int pages;
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int i;
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pages = 1 << order;
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/*
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* With kmemcheck enabled, we need to allocate a memory area for the
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* shadow bits as well.
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*/
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shadow = alloc_pages_node(node, flags | __GFP_NOTRACK, order);
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if (!shadow) {
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if (printk_ratelimit())
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printk(KERN_ERR "kmemcheck: failed to allocate "
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"shadow bitmap\n");
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return;
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}
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for(i = 0; i < pages; ++i)
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page[i].shadow = page_address(&shadow[i]);
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/*
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* Mark it as non-present for the MMU so that our accesses to
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* this memory will trigger a page fault and let us analyze
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* the memory accesses.
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*/
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kmemcheck_hide_pages(page, pages);
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}
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void kmemcheck_free_shadow(struct page *page, int order)
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{
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struct page *shadow;
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int pages;
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int i;
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if (!kmemcheck_page_is_tracked(page))
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return;
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pages = 1 << order;
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kmemcheck_show_pages(page, pages);
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shadow = virt_to_page(page[0].shadow);
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for(i = 0; i < pages; ++i)
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page[i].shadow = NULL;
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__free_pages(shadow, order);
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}
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void kmemcheck_slab_alloc(struct kmem_cache *s, gfp_t gfpflags, void *object,
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size_t size)
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{
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if (unlikely(!object)) /* Skip object if allocation failed */
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return;
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/*
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* Has already been memset(), which initializes the shadow for us
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* as well.
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*/
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if (gfpflags & __GFP_ZERO)
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return;
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/* No need to initialize the shadow of a non-tracked slab. */
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if (s->flags & SLAB_NOTRACK)
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return;
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if (!kmemcheck_enabled || gfpflags & __GFP_NOTRACK) {
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/*
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* Allow notracked objects to be allocated from
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* tracked caches. Note however that these objects
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* will still get page faults on access, they just
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* won't ever be flagged as uninitialized. If page
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* faults are not acceptable, the slab cache itself
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* should be marked NOTRACK.
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*/
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kmemcheck_mark_initialized(object, size);
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} else if (!s->ctor) {
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/*
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* New objects should be marked uninitialized before
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* they're returned to the called.
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*/
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kmemcheck_mark_uninitialized(object, size);
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}
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}
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void kmemcheck_slab_free(struct kmem_cache *s, void *object, size_t size)
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{
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/* TODO: RCU freeing is unsupported for now; hide false positives. */
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if (!s->ctor && !(s->flags & SLAB_DESTROY_BY_RCU))
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kmemcheck_mark_freed(object, size);
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}
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void kmemcheck_pagealloc_alloc(struct page *page, unsigned int order,
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gfp_t gfpflags)
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{
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int pages;
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if (gfpflags & (__GFP_HIGHMEM | __GFP_NOTRACK))
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return;
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pages = 1 << order;
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/*
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* NOTE: We choose to track GFP_ZERO pages too; in fact, they
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* can become uninitialized by copying uninitialized memory
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* into them.
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*/
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/* XXX: Can use zone->node for node? */
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kmemcheck_alloc_shadow(page, order, gfpflags, -1);
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if (gfpflags & __GFP_ZERO)
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kmemcheck_mark_initialized_pages(page, pages);
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else
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kmemcheck_mark_uninitialized_pages(page, pages);
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}
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