linux-kernel - Re: [Patch v2 2/4] mm/page_alloc.c: bad_[reason|flags] is not necessary when PageHWPoison

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: <3e7b4045-cd22-552a-c28d-1605a97bbdf7@arm.com>
Date:   Mon, 20 Jan 2020 11:58:04 +0530
From:   Anshuman Khandual <anshuman.khandual@....com>
To:     Wei Yang <richardw.yang@...ux.intel.com>, akpm@...ux-foundation.org
Cc:     linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        rientjes@...gle.com
Subject: Re: [Patch v2 2/4] mm/page_alloc.c: bad_[reason|flags] is not
 necessary when PageHWPoison



On 01/20/2020 08:34 AM, Wei Yang wrote:
> Since function returns directly, bad_[reason|flags] is not used any
> where.
> 
> This is a following cleanup for commit e570f56cccd21 ("mm:
> check_new_page_bad() directly returns in __PG_HWPOISON case")
> 
> Signed-off-by: Wei Yang <richardw.yang@...ux.intel.com>
> Acked-by: David Rientjes <rientjes@...gle.com>
> ---
>  mm/page_alloc.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 0cf6218aaba7..a43b9d2482f2 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -2051,8 +2051,6 @@ static void check_new_page_bad(struct page *page)
>  	if (unlikely(page_ref_count(page) != 0))
>  		bad_reason = "nonzero _refcount";
>  	if (unlikely(page->flags & __PG_HWPOISON)) {
> -		bad_reason = "HWPoisoned (hardware-corrupted)";
> -		bad_flags = __PG_HWPOISON;
>  		/* Don't complain about hwpoisoned pages */
>  		page_mapcount_reset(page); /* remove PageBuddy */
>  		return;

This bail out condition should be the first in the function
check_new_page_bad() before evaluating bad_[reason|flags]
as they will never be used.

>