* [PATCH] mm/memblock: skip kmemleak for kasan_init()
@ 2018-11-28 17:40 Qian Cai
2018-11-28 18:18 ` Catalin Marinas
0 siblings, 1 reply; 2+ messages in thread
From: Qian Cai @ 2018-11-28 17:40 UTC (permalink / raw)
To: akpm
Cc: catalin.marinas, mhocko, rppt, aryabinin, glider, dvyukov,
kasan-dev, linux-mm, linux-kernel, Qian Cai
Kmemleak does not play well with KASAN (tested on both HPE Apollo 70 and
Huawei TaiShan 2280 aarch64 servers).
After calling start_kernel()->setup_arch()->kasan_init(), kmemleak early
log buffer went from something like 280 to 260000 which caused kmemleak
disabled and crash dump memory reservation failed. The multitude of
kmemleak_alloc() calls is from,
for_each_memblock(memory, reg) x \
while (pgdp++, addr = next, addr != end) x \
while (pudp++, addr = next, addr != end && pud_none(READ_ONCE(*pudp))) \
while (pmdp++, addr = next, addr != end && pmd_none(READ_ONCE(*pmdp))) \
while (ptep++, addr = next, addr != end && pte_none(READ_ONCE(*ptep)))
Signed-off-by: Qian Cai <cai@gmx.us>
---
mm/memblock.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/mm/memblock.c b/mm/memblock.c
index 9a2d5ae..fd78e39 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -1412,6 +1412,8 @@ static void * __init memblock_alloc_internal(
done:
ptr = phys_to_virt(alloc);
+/* Skip kmemleak for kasan_init() due to high volume. */
+#ifndef CONFIG_KASAN
/*
* The min_count is set to 0 so that bootmem allocated blocks
* are never reported as leaks. This is because many of these blocks
@@ -1419,6 +1421,7 @@ static void * __init memblock_alloc_internal(
* looked up by kmemleak.
*/
kmemleak_alloc(ptr, size, 0, 0);
+#endif
return ptr;
}
--
1.8.3.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] mm/memblock: skip kmemleak for kasan_init()
2018-11-28 17:40 [PATCH] mm/memblock: skip kmemleak for kasan_init() Qian Cai
@ 2018-11-28 18:18 ` Catalin Marinas
0 siblings, 0 replies; 2+ messages in thread
From: Catalin Marinas @ 2018-11-28 18:18 UTC (permalink / raw)
To: Qian Cai
Cc: akpm, mhocko, rppt, aryabinin, glider, dvyukov, kasan-dev,
linux-mm, linux-kernel
On Wed, Nov 28, 2018 at 12:40:33PM -0500, Qian Cai wrote:
> Kmemleak does not play well with KASAN (tested on both HPE Apollo 70 and
> Huawei TaiShan 2280 aarch64 servers).
>
> After calling start_kernel()->setup_arch()->kasan_init(), kmemleak early
> log buffer went from something like 280 to 260000 which caused kmemleak
> disabled and crash dump memory reservation failed. The multitude of
> kmemleak_alloc() calls is from,
>
> for_each_memblock(memory, reg) x \
> while (pgdp++, addr = next, addr != end) x \
> while (pudp++, addr = next, addr != end && pud_none(READ_ONCE(*pudp))) \
> while (pmdp++, addr = next, addr != end && pmd_none(READ_ONCE(*pmdp))) \
> while (ptep++, addr = next, addr != end && pte_none(READ_ONCE(*ptep)))
>
> Signed-off-by: Qian Cai <cai@gmx.us>
Sorry, I didn't get the chance to investigate this further. Hopefully
early next week.
> diff --git a/mm/memblock.c b/mm/memblock.c
> index 9a2d5ae..fd78e39 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -1412,6 +1412,8 @@ static void * __init memblock_alloc_internal(
> done:
> ptr = phys_to_virt(alloc);
>
> +/* Skip kmemleak for kasan_init() due to high volume. */
> +#ifndef CONFIG_KASAN
> /*
> * The min_count is set to 0 so that bootmem allocated blocks
> * are never reported as leaks. This is because many of these blocks
> @@ -1419,6 +1421,7 @@ static void * __init memblock_alloc_internal(
> * looked up by kmemleak.
> */
> kmemleak_alloc(ptr, size, 0, 0);
> +#endif
This may render kmemleak unusable since it is not aware of the memblock
allocations and it would trigger lots of false positives.
--
Catalin
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