2015-04-17 02:09:57

by Naoya Horiguchi

Subject: [PATCH 1/2] mm/hwpoison-inject: fix refcounting in no-injection case

Hwpoison injection via debugfs:hwpoison/corrupt-pfn takes a refcount of
the target page. But current code doesn't release it if the target page
is not supposed to be injected, which results in memory leak.
This patch simply adds the refcount releasing code.

Signed-off-by: Naoya Horiguchi <[email protected]>
---
mm/hwpoison-inject.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git v4.0.orig/mm/hwpoison-inject.c v4.0/mm/hwpoison-inject.c
index 329caf56df22..2b3f933e3282 100644
--- v4.0.orig/mm/hwpoison-inject.c
+++ v4.0/mm/hwpoison-inject.c
@@ -40,7 +40,7 @@ static int hwpoison_inject(void *data, u64 val)
* This implies unable to support non-LRU pages.
*/
if (!PageLRU(p) && !PageHuge(p))
- return 0;
+ goto put_out;

/*
* do a racy check with elevated page count, to make sure PG_hwpoison
@@ -52,11 +52,14 @@ static int hwpoison_inject(void *data, u64 val)
err = hwpoison_filter(hpage);
unlock_page(hpage);
if (err)
- return 0;
+ goto put_out;

inject:
pr_info("Injecting memory failure at pfn %#lx\n", pfn);
return memory_failure(pfn, 18, MF_COUNT_INCREASED);
+put_out:
+ put_page(hpage);
+ return 0;
}

static int hwpoison_unpoison(void *data, u64 val)
--
2.1.0

2015-04-17 02:10:06

by Naoya Horiguchi

Subject: [PATCH 2/2] mm/hwpoison-inject: check PageLRU of hpage

Hwpoison injector checks PageLRU of the raw target page to find out whether
the page is an appropriate target, but current code now filters out thp tail
pages, which prevents us from testing for such cases via this interface.
So let's check hpage instead of p.

Signed-off-by: Naoya Horiguchi <[email protected]>
---
mm/hwpoison-inject.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git v4.0.orig/mm/hwpoison-inject.c v4.0/mm/hwpoison-inject.c
index 2b3f933e3282..4ca5fe0042e1 100644
--- v4.0.orig/mm/hwpoison-inject.c
+++ v4.0/mm/hwpoison-inject.c
@@ -34,12 +34,12 @@ static int hwpoison_inject(void *data, u64 val)
if (!hwpoison_filter_enable)
goto inject;

- if (!PageLRU(p) && !PageHuge(p))
- shake_page(p, 0);
+ if (!PageLRU(hpage) && !PageHuge(p))
+ shake_page(hpage, 0);
/*
* This implies unable to support non-LRU pages.
*/
- if (!PageLRU(p) && !PageHuge(p))
+ if (!PageLRU(hpage) && !PageHuge(p))
goto put_out;

/*
--
2.1.0

2015-04-24 00:42:43

by Dean Nelson

Subject: Re: [PATCH 1/2] mm/hwpoison-inject: fix refcounting in no-injection case

On 04/16/2015 09:08 PM, Naoya Horiguchi wrote:
> Hwpoison injection via debugfs:hwpoison/corrupt-pfn takes a refcount of
> the target page. But current code doesn't release it if the target page
> is not supposed to be injected, which results in memory leak.
> This patch simply adds the refcount releasing code.
>
> Signed-off-by: Naoya Horiguchi <[email protected]>

Acked-by: Dean Nelson <[email protected]>


> ---
> mm/hwpoison-inject.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git v4.0.orig/mm/hwpoison-inject.c v4.0/mm/hwpoison-inject.c
> index 329caf56df22..2b3f933e3282 100644
> --- v4.0.orig/mm/hwpoison-inject.c
> +++ v4.0/mm/hwpoison-inject.c
> @@ -40,7 +40,7 @@ static int hwpoison_inject(void *data, u64 val)
> * This implies unable to support non-LRU pages.
> */
> if (!PageLRU(p) && !PageHuge(p))
> - return 0;
> + goto put_out;
>
> /*
> * do a racy check with elevated page count, to make sure PG_hwpoison
> @@ -52,11 +52,14 @@ static int hwpoison_inject(void *data, u64 val)
> err = hwpoison_filter(hpage);
> unlock_page(hpage);
> if (err)
> - return 0;
> + goto put_out;
>
> inject:
> pr_info("Injecting memory failure at pfn %#lx\n", pfn);
> return memory_failure(pfn, 18, MF_COUNT_INCREASED);
> +put_out:
> + put_page(hpage);
> + return 0;
> }
>
> static int hwpoison_unpoison(void *data, u64 val)
>

2015-04-24 00:42:50

by Dean Nelson

Subject: Re: [PATCH 2/2] mm/hwpoison-inject: check PageLRU of hpage

On 04/16/2015 09:08 PM, Naoya Horiguchi wrote:
> Hwpoison injector checks PageLRU of the raw target page to find out whether
> the page is an appropriate target, but current code now filters out thp tail
> pages, which prevents us from testing for such cases via this interface.
> So let's check hpage instead of p.
>
> Signed-off-by: Naoya Horiguchi <[email protected]>

Acked-by: Dean Nelson <[email protected]>


> ---
> mm/hwpoison-inject.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git v4.0.orig/mm/hwpoison-inject.c v4.0/mm/hwpoison-inject.c
> index 2b3f933e3282..4ca5fe0042e1 100644
> --- v4.0.orig/mm/hwpoison-inject.c
> +++ v4.0/mm/hwpoison-inject.c
> @@ -34,12 +34,12 @@ static int hwpoison_inject(void *data, u64 val)
> if (!hwpoison_filter_enable)
> goto inject;
>
> - if (!PageLRU(p) && !PageHuge(p))
> - shake_page(p, 0);
> + if (!PageLRU(hpage) && !PageHuge(p))
> + shake_page(hpage, 0);
> /*
> * This implies unable to support non-LRU pages.
> */
> - if (!PageLRU(p) && !PageHuge(p))
> + if (!PageLRU(hpage) && !PageHuge(p))
> goto put_out;
>
> /*
>