linux-kernel - Re: [PATCH 1/2] mm/hwpoison: fix fail to split THP w/ refcount held

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20150810081019.GA21282@hori1.linux.bs1.fc.nec.co.jp>
Date:	Mon, 10 Aug 2015 08:10:20 +0000
From:	Naoya Horiguchi <n-horiguchi@...jp.nec.com>
To:	Wanpeng Li <wanpeng.li@...mail.com>
CC:	Andrew Morton <akpm@...ux-foundation.org>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] mm/hwpoison: fix fail to split THP w/ refcount held

On Mon, Aug 10, 2015 at 02:32:30PM +0800, Wanpeng Li wrote:
> THP pages will get a refcount in madvise_hwpoison() w/ MF_COUNT_INCREASED 
> flag, however, the refcount is still held when fail to split THP pages.
> 
> Fix it by reducing the refcount of THP pages when fail to split THP.
> 
> Signed-off-by: Wanpeng Li <wanpeng.li@...mail.com>

It seems that the same conditional put_page() would be added to
"soft offline: %#lx page already poisoned" branch too, right?

> ---
>  mm/memory-failure.c |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
> 
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index 8077b1c..56b8a71 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -1710,6 +1710,8 @@ int soft_offline_page(struct page *page, int flags)
>  		if (PageAnon(hpage) && unlikely(split_huge_page(hpage))) {
>  			pr_info("soft offline: %#lx: failed to split THP\n",
>  				pfn);
> +			if (flags & MF_COUNT_INCREASED)
> +				put_page(page);
>  			return -EBUSY;
>  		}
>  	}
> -- 
> 1.7.1
> 
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@...ck.org.  For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@...ck.org"> email@...ck.org </a>--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/