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authorCatalin Marinas <catalin.marinas@arm.com>2013-11-12 15:07:45 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-07-31 12:54:53 -0700
commit7e2e611849fa3786431f86411346ecb70c3f4283 (patch)
tree0112264978b0294d2dadc7d4ab049ea26b0dd230
parentb06b5c6204bdc7c571feedb6b16188ba62feb9a6 (diff)
mm: kmemleak: avoid false negatives on vmalloc'ed objects
commit 7f88f88f83ed609650a01b18572e605ea50cd163 upstream. Commit 248ac0e1943a ("mm/vmalloc: remove guard page from between vmap blocks") had the side effect of making vmap_area.va_end member point to the next vmap_area.va_start. This was creating an artificial reference to vmalloc'ed objects and kmemleak was rarely reporting vmalloc() leaks. This patch marks the vmap_area containing pointers explicitly and reduces the min ref_count to 2 as vm_struct still contains a reference to the vmalloc'ed object. The kmemleak add_scan_area() function has been improved to allow a SIZE_MAX argument covering the rest of the object (for simpler calling sites). Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> [hq: Backported to 3.4: Adjust context] Signed-off-by: Qiang Huang <h.huangqiang@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--mm/kmemleak.c4
-rw-r--r--mm/vmalloc.c14
2 files changed, 13 insertions, 5 deletions
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 45eb6217bf38..ad6ee88a3d48 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -750,7 +750,9 @@ static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp)
}
spin_lock_irqsave(&object->lock, flags);
- if (ptr + size > object->pointer + object->size) {
+ if (size == SIZE_MAX) {
+ size = object->pointer + object->size - ptr;
+ } else if (ptr + size > object->pointer + object->size) {
kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr);
dump_object_info(object);
kmem_cache_free(scan_area_cache, area);
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 1196c7728ede..ad9d90064a4b 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -349,6 +349,12 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
if (unlikely(!va))
return ERR_PTR(-ENOMEM);
+ /*
+ * Only scan the relevant parts containing pointers to other objects
+ * to avoid false negatives.
+ */
+ kmemleak_scan_area(&va->rb_node, SIZE_MAX, gfp_mask & GFP_RECLAIM_MASK);
+
retry:
spin_lock(&vmap_area_lock);
/*
@@ -1669,11 +1675,11 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align,
insert_vmalloc_vmlist(area);
/*
- * A ref_count = 3 is needed because the vm_struct and vmap_area
- * structures allocated in the __get_vm_area_node() function contain
- * references to the virtual address of the vmalloc'ed block.
+ * A ref_count = 2 is needed because vm_struct allocated in
+ * __get_vm_area_node() contains a reference to the virtual address of
+ * the vmalloc'ed block.
*/
- kmemleak_alloc(addr, real_size, 3, gfp_mask);
+ kmemleak_alloc(addr, real_size, 2, gfp_mask);
return addr;