From: Andrew Morton <akpm@linux-foundation.org>
To: Wei Yang <richard.weiyang@gmail.com>
Cc: mhocko@suse.com, yinghai@kernel.org, linux-mm@kvack.org,
hejianet@gmail.com, "3 . 12+" <stable@vger.kernel.org>
Subject: Re: [PATCH] mm/memblock: fix potential issue in memblock_search_pfn_nid()
Date: Fri, 30 Mar 2018 13:57:27 -0700 [thread overview]
Message-ID: <20180330135727.67251c7ea8c2db28b404e0e1@linux-foundation.org> (raw)
In-Reply-To: <20180330033055.22340-1-richard.weiyang@gmail.com>
On Fri, 30 Mar 2018 11:30:55 +0800 Wei Yang <richard.weiyang@gmail.com> wrote:
> memblock_search_pfn_nid() returns the nid and the [start|end]_pfn of the
> memory region where pfn sits in. While the calculation of start_pfn has
> potential issue when the regions base is not page aligned.
>
> For example, we assume PAGE_SHIFT is 12 and base is 0x1234. Current
> implementation would return 1 while this is not correct.
Why is this not correct? The caller might want the pfn of the page
which covers the base?
> This patch fixes this by using PFN_UP().
>
> The original commit is commit e76b63f80d93 ("memblock, numa: binary search
> node id") and merged in v3.12.
>
> Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
> Cc: 3.12+ <stable@vger.kernel.org>
Please fully describe the runtime effects of a bug when fixing that
bug. This description doesn't give enough justification for merging
the patch into mainline, let alone -stable.
next prev parent reply other threads:[~2018-03-30 20:57 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-30 3:30 [PATCH] mm/memblock: fix potential issue in memblock_search_pfn_nid() Wei Yang
2018-03-30 20:57 ` Andrew Morton [this message]
2018-04-02 1:50 ` Wei Yang
2018-04-03 11:30 ` Michal Hocko
2018-04-04 1:33 ` Wei Yang
2018-04-04 5:45 ` Michal Hocko
2018-04-06 1:35 ` Wei Yang
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