* [PATCH] 4.1.28 Fix bad backport of 8f182270dfec "mm/swap.c: flush lru pvecs on compound page arrival"
@ 2016-07-14 21:55 Steven Rostedt
2016-07-15 6:55 ` Michal Hocko
0 siblings, 1 reply; 3+ messages in thread
From: Steven Rostedt @ 2016-07-14 21:55 UTC (permalink / raw)
To: Sasha Levin; +Cc: stable, Andrew Morton, Michal Hocko
When I pulled in 4.1.28 into my stable 4.1-rt tree and ran the tests,
it crashed with a severe OOM killing everything. I then tested 4.1.28
without -rt and it had the same issue. I did a bisect between 4.1.27
and 4.1.28 and found that the bug started at:
commit 8f182270dfec "mm/swap.c: flush lru pvecs on compound page
arrival"
Looking at that patch and what's in mainline, I see that there's a
mismatch in one of the hunks:
Mainline:
@@ -391,9 +391,8 @@ static void __lru_cache_add(struct page *page)
struct pagevec *pvec = &get_cpu_var(lru_add_pvec);
get_page(page);
- if (!pagevec_space(pvec))
+ if (!pagevec_add(pvec, page) || PageCompound(page))
__pagevec_lru_add(pvec);
- pagevec_add(pvec, page);
put_cpu_var(lru_add_pvec);
}
Stable 4.1.28:
@@ -631,9 +631,8 @@ static void __lru_cache_add(struct page *page)
struct pagevec *pvec = &get_cpu_var(lru_add_pvec);
page_cache_get(page);
- if (!pagevec_space(pvec))
+ if (!pagevec_space(pvec) || PageCompound(page))
__pagevec_lru_add(pvec);
- pagevec_add(pvec, page);
put_cpu_var(lru_add_pvec);
}
Where mainline replace pagevec_space() with pagevec_add, and stable did
not.
Fixing this makes the OOM go away.
Note, 3.18 has the same bug.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
diff --git a/mm/swap.c b/mm/swap.c
index b523f0a4cbfb..ab3b9c2dd783 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -631,7 +631,7 @@ static void __lru_cache_add(struct page *page)
struct pagevec *pvec = &get_cpu_var(lru_add_pvec);
page_cache_get(page);
- if (!pagevec_space(pvec) || PageCompound(page))
+ if (!pagevec_add(pvec, page) || PageCompound(page))
__pagevec_lru_add(pvec);
put_cpu_var(lru_add_pvec);
}
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] 4.1.28 Fix bad backport of 8f182270dfec "mm/swap.c: flush lru pvecs on compound page arrival"
2016-07-14 21:55 [PATCH] 4.1.28 Fix bad backport of 8f182270dfec "mm/swap.c: flush lru pvecs on compound page arrival" Steven Rostedt
@ 2016-07-15 6:55 ` Michal Hocko
2016-07-15 11:51 ` Sasha Levin
0 siblings, 1 reply; 3+ messages in thread
From: Michal Hocko @ 2016-07-15 6:55 UTC (permalink / raw)
To: Steven Rostedt; +Cc: Sasha Levin, stable, Andrew Morton
On Thu 14-07-16 17:55:21, Steven Rostedt wrote:
> When I pulled in 4.1.28 into my stable 4.1-rt tree and ran the tests,
> it crashed with a severe OOM killing everything. I then tested 4.1.28
> without -rt and it had the same issue. I did a bisect between 4.1.27
> and 4.1.28 and found that the bug started at:
>
> commit 8f182270dfec "mm/swap.c: flush lru pvecs on compound page
> arrival"
>
> Looking at that patch and what's in mainline, I see that there's a
> mismatch in one of the hunks:
>
> Mainline:
>
> @@ -391,9 +391,8 @@ static void __lru_cache_add(struct page *page)
> struct pagevec *pvec = &get_cpu_var(lru_add_pvec);
>
> get_page(page);
> - if (!pagevec_space(pvec))
> + if (!pagevec_add(pvec, page) || PageCompound(page))
> __pagevec_lru_add(pvec);
> - pagevec_add(pvec, page);
> put_cpu_var(lru_add_pvec);
> }
>
>
> Stable 4.1.28:
>
> @@ -631,9 +631,8 @@ static void __lru_cache_add(struct page *page)
> struct pagevec *pvec = &get_cpu_var(lru_add_pvec);
>
> page_cache_get(page);
> - if (!pagevec_space(pvec))
> + if (!pagevec_space(pvec) || PageCompound(page))
> __pagevec_lru_add(pvec);
> - pagevec_add(pvec, page);
> put_cpu_var(lru_add_pvec);
> }
Heh, I've made the same mistake when backporting this to our older SLES
based kernel initially. I was lucky the system even didn't boot. Sorry
that I didn't find time to review the stable backport.
> Where mainline replace pagevec_space() with pagevec_add, and stable did
> not.
>
> Fixing this makes the OOM go away.
>
> Note, 3.18 has the same bug.
>
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Michal Hocko <mhocko@suse.com>
> ---
> diff --git a/mm/swap.c b/mm/swap.c
> index b523f0a4cbfb..ab3b9c2dd783 100644
> --- a/mm/swap.c
> +++ b/mm/swap.c
> @@ -631,7 +631,7 @@ static void __lru_cache_add(struct page *page)
> struct pagevec *pvec = &get_cpu_var(lru_add_pvec);
>
> page_cache_get(page);
> - if (!pagevec_space(pvec) || PageCompound(page))
> + if (!pagevec_add(pvec, page) || PageCompound(page))
> __pagevec_lru_add(pvec);
> put_cpu_var(lru_add_pvec);
> }
--
Michal Hocko
SUSE Labs
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] 4.1.28 Fix bad backport of 8f182270dfec "mm/swap.c: flush lru pvecs on compound page arrival"
2016-07-15 6:55 ` Michal Hocko
@ 2016-07-15 11:51 ` Sasha Levin
0 siblings, 0 replies; 3+ messages in thread
From: Sasha Levin @ 2016-07-15 11:51 UTC (permalink / raw)
To: Michal Hocko, Steven Rostedt; +Cc: stable, Andrew Morton
On 07/15/2016 02:55 AM, Michal Hocko wrote:
> On Thu 14-07-16 17:55:21, Steven Rostedt wrote:
>> > When I pulled in 4.1.28 into my stable 4.1-rt tree and ran the tests,
>> > it crashed with a severe OOM killing everything. I then tested 4.1.28
>> > without -rt and it had the same issue. I did a bisect between 4.1.27
>> > and 4.1.28 and found that the bug started at:
>> >
>> > commit 8f182270dfec "mm/swap.c: flush lru pvecs on compound page
>> > arrival"
>> >
>> > Looking at that patch and what's in mainline, I see that there's a
>> > mismatch in one of the hunks:
>> >
>> > Mainline:
>> >
>> > @@ -391,9 +391,8 @@ static void __lru_cache_add(struct page *page)
>> > struct pagevec *pvec = &get_cpu_var(lru_add_pvec);
>> >
>> > get_page(page);
>> > - if (!pagevec_space(pvec))
>> > + if (!pagevec_add(pvec, page) || PageCompound(page))
>> > __pagevec_lru_add(pvec);
>> > - pagevec_add(pvec, page);
>> > put_cpu_var(lru_add_pvec);
>> > }
>> >
>> >
>> > Stable 4.1.28:
>> >
>> > @@ -631,9 +631,8 @@ static void __lru_cache_add(struct page *page)
>> > struct pagevec *pvec = &get_cpu_var(lru_add_pvec);
>> >
>> > page_cache_get(page);
>> > - if (!pagevec_space(pvec))
>> > + if (!pagevec_space(pvec) || PageCompound(page))
>> > __pagevec_lru_add(pvec);
>> > - pagevec_add(pvec, page);
>> > put_cpu_var(lru_add_pvec);
>> > }
> Heh, I've made the same mistake when backporting this to our older SLES
> based kernel initially. I was lucky the system even didn't boot. Sorry
> that I didn't find time to review the stable backport.
>
Thanks all! I've queued the fix.
Thanks,
Sasha
^ permalink raw reply [flat|nested] 3+ messages in thread
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2016-07-14 21:55 [PATCH] 4.1.28 Fix bad backport of 8f182270dfec "mm/swap.c: flush lru pvecs on compound page arrival" Steven Rostedt
2016-07-15 6:55 ` Michal Hocko
2016-07-15 11:51 ` Sasha Levin
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