From: Michal Hocko <mhocko@kernel.org>
To: Qian Cai <cai@lca.pw>
Cc: akpm@linux-foundation.org, mingo@kernel.org, hpa@zytor.com,
mgorman@techsingularity.net, tglx@linutronix.de,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: skip checking poison pattern for page_to_nid()
Date: Wed, 19 Dec 2018 11:20:10 +0100 [thread overview]
Message-ID: <20181219102010.GF5758@dhcp22.suse.cz> (raw)
In-Reply-To: <20181219015732.26179-1-cai@lca.pw>
On Tue 18-12-18 20:57:32, Qian Cai wrote:
[...]
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 5411de93a363..f083f366ea90 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -985,9 +985,7 @@ extern int page_to_nid(const struct page *page);
> #else
> static inline int page_to_nid(const struct page *page)
> {
> - struct page *p = (struct page *)page;
> -
> - return (PF_POISONED_CHECK(p)->flags >> NODES_PGSHIFT) & NODES_MASK;
> + return (page->flags >> NODES_PGSHIFT) & NODES_MASK;
> }
> #endif
I didn't get to think about a proper fix but this is clearly worng. If
the page is still poisoned then flags are clearly bogus and the node you
get is a garbage as well. Have you actually tested this patch?
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2018-12-19 10:20 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1545172285.18411.26.camel@lca.pw>
2018-12-19 1:57 ` [PATCH] mm: skip checking poison pattern for page_to_nid() Qian Cai
2018-12-19 10:20 ` Michal Hocko [this message]
2018-12-19 12:46 ` Qian Cai
2018-12-20 6:03 ` [PATCH] mm/page_owner: fix for deferred struct page init Qian Cai
2018-12-20 9:22 ` Michal Hocko
2018-12-20 18:50 ` [PATCH v2] " Qian Cai
2018-12-20 20:31 ` [PATCH v3] " Qian Cai
2018-12-20 21:00 ` William Kucharski
2018-12-20 21:04 ` Qian Cai
2019-01-03 11:51 ` Michal Hocko
2019-01-03 16:38 ` Qian Cai
2019-01-03 16:59 ` Michal Hocko
2019-01-03 17:38 ` Qian Cai
2019-01-03 19:07 ` Michal Hocko
2019-01-03 19:53 ` Qian Cai
2019-01-03 20:22 ` Michal Hocko
2019-01-03 22:22 ` Qian Cai
2019-01-04 13:09 ` Michal Hocko
2019-01-04 15:01 ` Qian Cai
2019-01-04 15:17 ` Michal Hocko
2019-01-04 15:25 ` Qian Cai
2019-01-04 15:32 ` Michal Hocko
2019-01-04 20:18 ` Qian Cai
2019-01-07 18:43 ` Michal Hocko
2019-01-08 1:53 ` Qian Cai
2019-01-08 8:20 ` Michal Hocko
2019-01-08 13:19 ` Qian Cai
2019-01-08 22:02 ` Andrew Morton
2019-01-08 22:13 ` Qian Cai
2019-01-08 22:40 ` Michal Hocko
2019-01-09 7:34 ` [PATCH v2] " Michal Hocko
2019-01-15 20:28 ` [PATCH] Revert "mm: use early_pfn_to_nid in page_ext_init" Qian Cai
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20181219102010.GF5758@dhcp22.suse.cz \
--to=mhocko@kernel.org \
--cc=akpm@linux-foundation.org \
--cc=cai@lca.pw \
--cc=hpa@zytor.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@techsingularity.net \
--cc=mingo@kernel.org \
--cc=tglx@linutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).