On Wed, May 24, 2017 at 02:02:04PM +0100, James Morse wrote:
> memory_failure() chooses a recovery action function based on the page
> flags. For huge pages it uses the tail page flags which don't have
> anything interesting set, resulting in:
> > Memory failure: 0x9be3b4: Unknown page state
> > Memory failure: 0x9be3b4: recovery action for unknown page: Failed
>
> Instead, save a copy of the head page's flags if this is a huge page,
> this means if there are no relevant flags for this tail page, we use
> the head pages flags instead. This results in the me_huge_page()
> recovery action being called:
> > Memory failure: 0x9b7969: recovery action for huge page: Delayed
>
> For hugepages that have not yet been allocated, this allows the hugepage
> to be dequeued.
>
> CC: Punit Agrawal <punit.agrawal@xxxxxxx>
> Signed-off-by: James Morse <james.morse@xxxxxxx>
Looks good to me.
Acked-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
> ---
> This is intended as a fix, but I can't find the patch that introduced this
> behaviour. (not recent, and there is a lot of history down there!)
Please add a tag
Fixes: 524fca1e7356 ("HWPOISON: fix misjudgement of page_action() for errors on mlocked pages")
>
> This doesn't apply to stable trees before v3.10...
> Cc: stable@xxxxxxxxxxxxxxx # 3.10.105
You can skip older stable kernels to which the fix isn't cleanly applicable.
Thanks,
Naoya Horiguchi
>
> mm/memory-failure.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index 2527dfeddb00..44a6a33af219 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -1184,7 +1184,10 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
> * page_remove_rmap() in try_to_unmap_one(). So to determine page status
> * correctly, we save a copy of the page flags at this time.
> */
> - page_flags = p->flags;
> + if (PageHuge(p))
> + page_flags = hpage->flags;
> + else
> + page_flags = p->flags;
>
> /*
> * unpoison always clear PG_hwpoison inside page lock
> --
> 2.11.0
>
>
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