kmemcheck: remove annotations

Patch series "kmemcheck: kill kmemcheck", v2.

As discussed at LSF/MM, kill kmemcheck.

KASan is a replacement that is able to work without the limitation of
kmemcheck (single CPU, slow).  KASan is already upstream.

We are also not aware of any users of kmemcheck (or users who don't
consider KASan as a suitable replacement).

The only objection was that since KASAN wasn't supported by all GCC
versions provided by distros at that time we should hold off for 2
years, and try again.

Now that 2 years have passed, and all distros provide gcc that supports
KASAN, kill kmemcheck again for the very same reasons.

This patch (of 4):

Remove kmemcheck annotations, and calls to kmemcheck from the kernel.

[alexander.levin@verizon.com: correctly remove kmemcheck call from dma_map_sg_attrs]
  Link: http://lkml.kernel.org/r/20171012192151.26531-1-alexander.levin@verizon.com
Link: http://lkml.kernel.org/r/20171007030159.22241-2-alexander.levin@verizon.com
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tim Hansen <devtimhansen@gmail.com>
Cc: Vegard Nossum <vegardno@ifi.uio.no>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

5 files changed, 0 insertions, 59 deletions

diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index fca3452..e4738d5 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -110,7 +110,6 @@
 #include <linux/atomic.h>
 
 #include <linux/kasan.h>
-#include <linux/kmemcheck.h>
 #include <linux/kmemleak.h>
 #include <linux/memory_hotplug.h>
 
@@ -1238,9 +1237,6 @@ static bool update_checksum(struct kmemleak_object *object)
 {
 	u32 old_csum = object->checksum;
 
-	if (!kmemcheck_is_obj_initialized(object->pointer, object->size))
-		return false;
-
 	kasan_disable_current();
 	object->checksum = crc32(0, (void *)object->pointer, object->size);
 	kasan_enable_current();
@@ -1314,11 +1310,6 @@ static void scan_block(void *_start, void *_end,
 		if (scan_should_stop())
 			break;
 
-		/* don't scan uninitialized memory */
-		if (!kmemcheck_is_obj_initialized((unsigned long)ptr,
-						  BYTES_PER_POINTER))
-			continue;
-
 		kasan_disable_current();
 		pointer = *ptr;
 		kasan_enable_current();
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e6106d7..30a464b 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -24,7 +24,6 @@
 #include <linux/memblock.h>
 #include <linux/compiler.h>
 #include <linux/kernel.h>
-#include <linux/kmemcheck.h>
 #include <linux/kasan.h>
 #include <linux/module.h>
 #include <linux/suspend.h>
@@ -1013,7 +1012,6 @@ static __always_inline bool free_pages_prepare(struct page *page,
 	VM_BUG_ON_PAGE(PageTail(page), page);
 
 	trace_mm_page_free(page, order);
-	kmemcheck_free_shadow(page, order);
 
 	/*
 	 * Check tail pages before head page information is cleared to
@@ -2669,15 +2667,6 @@ void split_page(struct page *page, unsigned int order)
 	VM_BUG_ON_PAGE(PageCompound(page), page);
 	VM_BUG_ON_PAGE(!page_count(page), page);
 
-#ifdef CONFIG_KMEMCHECK
-	/*
-	 * Split shadow pages too, because free(page[0]) would
-	 * otherwise free the whole shadow.
-	 */
-	if (kmemcheck_page_is_tracked(page))
-		split_page(virt_to_page(page[0].shadow), order);
-#endif
-
 	for (i = 1; i < (1 << order); i++)
 		set_page_refcounted(page + i);
 	split_page_owner(page, order);
@@ -4223,9 +4212,6 @@ out:
 		page = NULL;
 	}
 
-	if (kmemcheck_enabled && page)
-		kmemcheck_pagealloc_alloc(page, order, gfp_mask);
-
 	trace_mm_page_alloc(page, order, alloc_mask, ac.migratetype);
 
 	return page;
diff --git a/mm/slab.c b/mm/slab.c
index 7a5e088..c84365e 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -114,7 +114,6 @@
 #include	<linux/rtmutex.h>
 #include	<linux/reciprocal_div.h>
 #include	<linux/debugobjects.h>
-#include	<linux/kmemcheck.h>
 #include	<linux/memory.h>
 #include	<linux/prefetch.h>
 #include	<linux/sched/task_stack.h>
@@ -1433,15 +1432,6 @@ static struct page *kmem_getpages(struct kmem_cache *cachep, gfp_t flags,
 	if (sk_memalloc_socks() && page_is_pfmemalloc(page))
 		SetPageSlabPfmemalloc(page);
 
-	if (kmemcheck_enabled && !(cachep->flags & SLAB_NOTRACK)) {
-		kmemcheck_alloc_shadow(page, cachep->gfporder, flags, nodeid);
-
-		if (cachep->ctor)
-			kmemcheck_mark_uninitialized_pages(page, nr_pages);
-		else
-			kmemcheck_mark_unallocated_pages(page, nr_pages);
-	}
-
 	return page;
 }
 
@@ -1453,8 +1443,6 @@ static void kmem_freepages(struct kmem_cache *cachep, struct page *page)
 	int order = cachep->gfporder;
 	unsigned long nr_freed = (1 << order);
 
-	kmemcheck_free_shadow(page, order);
-
 	if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
 		mod_lruvec_page_state(page, NR_SLAB_RECLAIMABLE, -nr_freed);
 	else
@@ -3515,8 +3503,6 @@ void ___cache_free(struct kmem_cache *cachep, void *objp,
 	kmemleak_free_recursive(objp, cachep->flags);
 	objp = cache_free_debugcheck(cachep, objp, caller);
 
-	kmemcheck_slab_free(cachep, objp, cachep->object_size);
-
 	/*
 	 * Skip calling cache_free_alien() when the platform is not numa.
 	 * This will avoid cache misses that happen while accessing slabp (which
diff --git a/mm/slab.h b/mm/slab.h
index e192556..e60a3d1 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -40,7 +40,6 @@ struct kmem_cache {
 
 #include <linux/memcontrol.h>
 #include <linux/fault-inject.h>
-#include <linux/kmemcheck.h>
 #include <linux/kasan.h>
 #include <linux/kmemleak.h>
 #include <linux/random.h>
@@ -439,7 +438,6 @@ static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags,
 	for (i = 0; i < size; i++) {
 		void *object = p[i];
 
-		kmemcheck_slab_alloc(s, flags, object, slab_ksize(s));
 		kmemleak_alloc_recursive(object, s->object_size, 1,
 					 s->flags, flags);
 		kasan_slab_alloc(s, object, flags);
diff --git a/mm/slub.c b/mm/slub.c
index 51484f0..ac3b50b 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -22,7 +22,6 @@
 #include <linux/notifier.h>
 #include <linux/seq_file.h>
 #include <linux/kasan.h>
-#include <linux/kmemcheck.h>
 #include <linux/cpu.h>
 #include <linux/cpuset.h>
 #include <linux/mempolicy.h>
@@ -1377,7 +1376,6 @@ static inline void *slab_free_hook(struct kmem_cache *s, void *x)
 		unsigned long flags;
 
 		local_irq_save(flags);
-		kmemcheck_slab_free(s, x, s->object_size);
 		debug_check_no_locks_freed(x, s->object_size);
 		local_irq_restore(flags);
 	}
@@ -1598,22 +1596,6 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
 		stat(s, ORDER_FALLBACK);
 	}
 
-	if (kmemcheck_enabled &&
-	    !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) {
-		int pages = 1 << oo_order(oo);
-
-		kmemcheck_alloc_shadow(page, oo_order(oo), alloc_gfp, node);
-
-		/*
-		 * Objects from caches that have a constructor don't get
-		 * cleared when they're allocated, so we need to do it here.
-		 */
-		if (s->ctor)
-			kmemcheck_mark_uninitialized_pages(page, pages);
-		else
-			kmemcheck_mark_unallocated_pages(page, pages);
-	}
-
 	page->objects = oo_objects(oo);
 
 	order = compound_order(page);
@@ -1689,8 +1671,6 @@ static void __free_slab(struct kmem_cache *s, struct page *page)
 			check_object(s, page, p, SLUB_RED_INACTIVE);
 	}
 
-	kmemcheck_free_shadow(page, compound_order(page));
-
 	mod_lruvec_page_state(page,
 		(s->flags & SLAB_RECLAIM_ACCOUNT) ?
 		NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,