From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
To: David Hildenbrand <david@redhat.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@kernel.org>
Subject: Re: [PATCH v2 2/2] mm/memory-failure.c: Don't access uninitialized memmaps in memory_failure()
Date: Thu, 10 Oct 2019 00:26:19 +0000 [thread overview]
Message-ID: <20191010002619.GB3585@hori.linux.bs1.fc.nec.co.jp> (raw)
In-Reply-To: <20191009142435.3975-3-david@redhat.com>
On Wed, Oct 09, 2019 at 04:24:35PM +0200, David Hildenbrand wrote:
> We should check for pfn_to_online_page() to not access uninitialized
> memmaps. Reshuffle the code so we don't have to duplicate the error
> message.
>
> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Michal Hocko <mhocko@kernel.org>
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
> mm/memory-failure.c | 14 ++++++++------
> 1 file changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index 7ef849da8278..e866e6e5660b 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -1253,17 +1253,19 @@ int memory_failure(unsigned long pfn, int flags)
> if (!sysctl_memory_failure_recovery)
> panic("Memory failure on page %lx", pfn);
>
> - if (!pfn_valid(pfn)) {
> + p = pfn_to_online_page(pfn);
> + if (!p) {
> + if (pfn_valid(pfn)) {
> + pgmap = get_dev_pagemap(pfn, NULL);
> + if (pgmap)
> + return memory_failure_dev_pagemap(pfn, flags,
> + pgmap);
> + }
> pr_err("Memory failure: %#lx: memory outside kernel control\n",
> pfn);
> return -ENXIO;
> }
>
> - pgmap = get_dev_pagemap(pfn, NULL);
> - if (pgmap)
> - return memory_failure_dev_pagemap(pfn, flags, pgmap);
> -
> - p = pfn_to_page(pfn);
This change seems to assume that memory_failure_dev_pagemap() is never
called for online pages. Is it an intended behavior?
Or the concept "online pages" is not applicable to zone device pages?
Thanks,
Naoya Horiguchi
next prev parent reply other threads:[~2019-10-10 0:27 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-09 14:24 [PATCH v2 0/2] mm: Don't access uninitialized memmaps in PFN walkers David Hildenbrand
2019-10-09 14:24 ` [PATCH v2 1/2] mm: Don't access uninitialized memmaps in fs/proc/page.c David Hildenbrand
2019-10-09 14:41 ` Michal Hocko
2019-10-14 8:44 ` David Hildenbrand
2019-10-09 14:24 ` [PATCH v2 2/2] mm/memory-failure.c: Don't access uninitialized memmaps in memory_failure() David Hildenbrand
2019-10-09 14:43 ` Michal Hocko
2019-10-10 7:27 ` David Hildenbrand
2019-10-10 7:35 ` Michal Hocko
2019-10-10 7:52 ` David Hildenbrand
2019-10-10 7:58 ` David Hildenbrand
2019-10-11 6:02 ` Naoya Horiguchi
2019-10-11 10:13 ` David Hildenbrand
2019-10-14 13:36 ` Michal Hocko
2019-10-15 14:23 ` Oscar Salvador
2019-10-10 0:26 ` Naoya Horiguchi [this message]
2019-10-10 7:17 ` David Hildenbrand
2019-10-11 6:50 ` Naoya Horiguchi
2019-10-19 2:05 ` Andrew Morton
2019-10-21 9:44 ` David Hildenbrand
2019-10-14 8:41 ` David Hildenbrand
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