The patch titled
Subject: kasan: fix kmemleak false-positive in kasan_module_alloc()
has been added to the -mm tree. Its filename is
kasan-fix-kmemleak-false-positive-in-kasan_module_alloc.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/kasan-fix-kmemleak-false-positive-in-kasan_module_alloc.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/kasan-fix-kmemleak-false-positive-in-kasan_module_alloc.patch
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------------------------------------------------------
From: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Subject: 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@xxxxxxxxxxxxx>
Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/kasan/kasan.c | 2 ++
1 file changed, 2 insertions(+)
diff -puN mm/kasan/kasan.c~kasan-fix-kmemleak-false-positive-in-kasan_module_alloc mm/kasan/kasan.c
--- a/mm/kasan/kasan.c~kasan-fix-kmemleak-false-positive-in-kasan_module_alloc
+++ a/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_
if (ret) {
find_vm_area(addr)->flags |= VM_KASAN;
+ kmemleak_ignore(ret);
return 0;
}
_
Patches currently in -mm which might be from aryabinin@xxxxxxxxxxxxx are
kasan-fix-kmemleak-false-positive-in-kasan_module_alloc.patch
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