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| author | Catalin Marinas <catalin.marinas@arm.com> | 2013-11-13 03:07:45 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-11-13 07:09:07 +0400 |
| commit | 7f88f88f83ed609650a01b18572e605ea50cd163 (patch) | |
| tree | 7a515679de2418dbf006bdc40c23b8c6f6b73fce | |
| parent | 81556b02525181e19ef073a798ba9d48db96f708 (diff) | |
| download | linux-7f88f88f83ed609650a01b18572e605ea50cd163.tar.xz | |
mm: kmemleak: avoid false negatives on vmalloc'ed objects
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>
| -rw-r--r-- | mm/kmemleak.c | 4 | ||||
| -rw-r--r-- | mm/vmalloc.c | 14 |
2 files changed, 13 insertions, 5 deletions
diff --git a/mm/kmemleak.c b/mm/kmemleak.c index e126b0ef9ad2..31f01c5011e5 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -753,7 +753,9 @@ 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 745fa9567475..0fdf96803c5b 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -359,6 +359,12 @@ 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); /* @@ -1645,11 +1651,11 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, clear_vm_uninitialized_flag(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; |