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| author | Catalin Marinas <catalin.marinas@arm.com> | 2013-11-12 15:07:45 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-11-13 12:09:07 +0900 |
| commit | 7f88f88f83ed609650a01b18572e605ea50cd163 (patch) | |
| tree | 7a515679de2418dbf006bdc40c23b8c6f6b73fce /mm/vmalloc.c | |
| parent | 81556b02525181e19ef073a798ba9d48db96f708 (diff) | |
| download | linux-7f88f88f83ed609650a01b18572e605ea50cd163.tar.bz2 | |
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>
Diffstat (limited to 'mm/vmalloc.c')
| -rw-r--r-- | mm/vmalloc.c | 14 |
1 files changed, 10 insertions, 4 deletions
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; |