Commit 80552f0f authored by Qian Cai's avatar Qian Cai Committed by Borislav Petkov
Browse files

mm/slab: Remove store_stackinfo() 



store_stackinfo() does not seem used in actual SLAB debugging.
Potentially, it could be added to check_poison_obj() to provide more
information but this seems like an overkill due to the declining
popularity of SLAB, so just remove it instead.

Signed-off-by: default avatarQian Cai <cai@lca.pw>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Acked-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: linux-mm <linux-mm@kvack.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: rientjes@google.com
Cc: sean.j.christopherson@intel.com
Link: https://lkml.kernel.org/r/20190416142258.18694-1-cai@lca.pw
parent dc4060a5

mm/slab.c

+6 −42
Original line number Diff line number Diff line
@@ -1467,53 +1467,17 @@ static bool is_debug_pagealloc_cache(struct kmem_cache *cachep) 
}



#ifdef CONFIG_DEBUG_PAGEALLOC

static void store_stackinfo(struct kmem_cache *cachep, unsigned long *addr,

			    unsigned long caller)

{

	int size = cachep->object_size;



	addr = (unsigned long *)&((char *)addr)[obj_offset(cachep)];



	if (size < 5 * sizeof(unsigned long))

		return;



	*addr++ = 0x12345678;

	*addr++ = caller;

	*addr++ = smp_processor_id();

	size -= 3 * sizeof(unsigned long);

	{

		unsigned long *sptr = &caller;

		unsigned long svalue;



		while (!kstack_end(sptr)) {

			svalue = *sptr++;

			if (kernel_text_address(svalue)) {

				*addr++ = svalue;

				size -= sizeof(unsigned long);

				if (size <= sizeof(unsigned long))

					break;

			}

		}



	}

	*addr++ = 0x87654321;

}



static void slab_kernel_map(struct kmem_cache *cachep, void *objp,

				int map, unsigned long caller)

static void slab_kernel_map(struct kmem_cache *cachep, void *objp, int map)

{

	if (!is_debug_pagealloc_cache(cachep))

		return;



	if (caller)

		store_stackinfo(cachep, objp, caller);



	kernel_map_pages(virt_to_page(objp), cachep->size / PAGE_SIZE, map);

}



#else

static inline void slab_kernel_map(struct kmem_cache *cachep, void *objp,

				int map, unsigned long caller) {}

				int map) {}



#endif
@@ -1661,7 +1625,7 @@ static void slab_destroy_debugcheck(struct kmem_cache *cachep, 


		if (cachep->flags & SLAB_POISON) {

			check_poison_obj(cachep, objp);

			slab_kernel_map(cachep, objp, 1, 0);

			slab_kernel_map(cachep, objp, 1);

		}

		if (cachep->flags & SLAB_RED_ZONE) {

			if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
@@ -2434,7 +2398,7 @@ static void cache_init_objs_debug(struct kmem_cache *cachep, struct page *page) 
		/* need to poison the objs? */

		if (cachep->flags & SLAB_POISON) {

			poison_obj(cachep, objp, POISON_FREE);

			slab_kernel_map(cachep, objp, 0, 0);

			slab_kernel_map(cachep, objp, 0);

		}

	}

#endif
@@ -2813,7 +2777,7 @@ static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp, 


	if (cachep->flags & SLAB_POISON) {

		poison_obj(cachep, objp, POISON_FREE);

		slab_kernel_map(cachep, objp, 0, caller);

		slab_kernel_map(cachep, objp, 0);

	}

	return objp;

}
@@ -3077,7 +3041,7 @@ static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep, 
		return objp;

	if (cachep->flags & SLAB_POISON) {

		check_poison_obj(cachep, objp);

		slab_kernel_map(cachep, objp, 1, 0);

		slab_kernel_map(cachep, objp, 1);

		poison_obj(cachep, objp, POISON_INUSE);

	}

	if (cachep->flags & SLAB_STORE_USER)

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