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authorAndrey Ryabinin <aryabinin@virtuozzo.com>2015-11-20 15:57:18 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-11-20 16:17:32 -0800
commit459372545c9c0d6f491e280dccc8a54a61b60e56 (patch)
tree3a49c12179dc5c0473f0d4e3716fe44af3c8069b /mm/kasan
parent928a477102c4fc6739883415b66987207e3502f4 (diff)
downloadlinux-459372545c9c0d6f491e280dccc8a54a61b60e56.tar.bz2
kasan: fix kmemleak false-positive in kasan_module_alloc()
Kmemleak reports the following leak: unreferenced object 0xfffffbfff41ea000 (size 20480): comm "modprobe", pid 65199, jiffies 4298875551 (age 542.568s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffff82354f5e>] kmemleak_alloc+0x4e/0xc0 [<ffffffff8152e718>] __vmalloc_node_range+0x4b8/0x740 [<ffffffff81574072>] kasan_module_alloc+0x72/0xc0 [<ffffffff810efe68>] module_alloc+0x78/0xb0 [<ffffffff812f6a24>] module_alloc_update_bounds+0x14/0x70 [<ffffffff812f8184>] layout_and_allocate+0x16f4/0x3c90 [<ffffffff812faa1f>] load_module+0x2ff/0x6690 [<ffffffff813010b6>] SyS_finit_module+0x136/0x170 [<ffffffff8239bbc9>] system_call_fastpath+0x16/0x1b [<ffffffffffffffff>] 0xffffffffffffffff kasan_module_alloc() allocates shadow memory for module and frees it on module unloading. It doesn't store the pointer to allocated shadow memory because it could be calculated from the shadowed address, i.e. kasan_mem_to_shadow(addr). Since kmemleak cannot find pointer to allocated shadow, it thinks that memory leaked. Use kmemleak_ignore() to tell kmemleak that this is not a leak and shadow memory doesn't contain any pointers. Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Acked-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/kasan')
-rw-r--r--mm/kasan/kasan.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c
index d41b21bce6a0..bc0a8d8b8f42 100644
--- a/mm/kasan/kasan.c
+++ b/mm/kasan/kasan.c
@@ -19,6 +19,7 @@
#include <linux/export.h>
#include <linux/init.h>
#include <linux/kernel.h>
+#include <linux/kmemleak.h>
#include <linux/memblock.h>
#include <linux/memory.h>
#include <linux/mm.h>
@@ -444,6 +445,7 @@ int kasan_module_alloc(void *addr, size_t size)
if (ret) {
find_vm_area(addr)->flags |= VM_KASAN;
+ kmemleak_ignore(ret);
return 0;
}