From: Mike Rapoport <rppt@kernel.org>
To: David Hildenbrand <david@redhat.com>
Cc: linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
"Michael S. Tsirkin" <mst@redhat.com>,
Jason Wang <jasowang@redhat.com>,
Alexey Dobriyan <adobriyan@gmail.com>,
"Matthew Wilcox (Oracle)" <willy@infradead.org>,
Oscar Salvador <osalvador@suse.de>,
Michal Hocko <mhocko@suse.com>, Roman Gushchin <guro@fb.com>,
Alex Shi <alex.shi@linux.alibaba.com>,
Steven Price <steven.price@arm.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
Aili Yao <yaoaili@kingsoft.com>, Jiri Bohac <jbohac@suse.cz>,
"K. Y. Srinivasan" <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Stephen Hemminger <sthemmin@microsoft.com>,
Wei Liu <wei.liu@kernel.org>,
Naoya Horiguchi <naoya.horiguchi@nec.com>,
linux-hyperv@vger.kernel.org,
virtualization@lists.linux-foundation.org,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH v1 3/7] mm: rename and move page_is_poisoned()
Date: Sun, 2 May 2021 09:32:14 +0300 [thread overview]
Message-ID: <YI5HbhYPfENdQAre@kernel.org> (raw)
In-Reply-To: <20210429122519.15183-4-david@redhat.com>
On Thu, Apr 29, 2021 at 02:25:15PM +0200, David Hildenbrand wrote:
> Commit d3378e86d182 ("mm/gup: check page posion status for coredump.")
> introduced page_is_poisoned(), however, v5 [1] of the patch used
> "page_is_hwpoison()" and something went wrong while upstreaming. Rename the
> function and move it to page-flags.h, from where it can be used in other
> -- kcore -- context.
>
> Move the comment to the place where it belongs and simplify.
>
> [1] https://lkml.kernel.org/r/20210322193318.377c9ce9@alex-virtual-machine
>
> Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
> ---
> include/linux/page-flags.h | 7 +++++++
> mm/gup.c | 6 +++++-
> mm/internal.h | 20 --------------------
> 3 files changed, 12 insertions(+), 21 deletions(-)
Nice :)
>
> diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
> index 04a34c08e0a6..b8c56672a588 100644
> --- a/include/linux/page-flags.h
> +++ b/include/linux/page-flags.h
> @@ -694,6 +694,13 @@ PAGEFLAG_FALSE(DoubleMap)
> TESTSCFLAG_FALSE(DoubleMap)
> #endif
>
> +static inline bool is_page_hwpoison(struct page *page)
> +{
> + if (PageHWPoison(page))
> + return true;
> + return PageHuge(page) && PageHWPoison(compound_head(page));
> +}
> +
> /*
> * For pages that are never mapped to userspace (and aren't PageSlab),
> * page_type may be used. Because it is initialised to -1, we invert the
> diff --git a/mm/gup.c b/mm/gup.c
> index ef7d2da9f03f..000f3303e7f2 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -1536,7 +1536,11 @@ struct page *get_dump_page(unsigned long addr)
> if (locked)
> mmap_read_unlock(mm);
>
> - if (ret == 1 && is_page_poisoned(page))
> + /*
> + * We might have hwpoisoned pages still mapped into user space. Don't
> + * read these pages when creating a coredump, access could be fatal.
> + */
> + if (ret == 1 && is_page_hwpoison(page))
> return NULL;
>
> return (ret == 1) ? page : NULL;
> diff --git a/mm/internal.h b/mm/internal.h
> index cb3c5e0a7799..1432feec62df 100644
> --- a/mm/internal.h
> +++ b/mm/internal.h
> @@ -97,26 +97,6 @@ static inline void set_page_refcounted(struct page *page)
> set_page_count(page, 1);
> }
>
> -/*
> - * When kernel touch the user page, the user page may be have been marked
> - * poison but still mapped in user space, if without this page, the kernel
> - * can guarantee the data integrity and operation success, the kernel is
> - * better to check the posion status and avoid touching it, be good not to
> - * panic, coredump for process fatal signal is a sample case matching this
> - * scenario. Or if kernel can't guarantee the data integrity, it's better
> - * not to call this function, let kernel touch the poison page and get to
> - * panic.
> - */
> -static inline bool is_page_poisoned(struct page *page)
> -{
> - if (PageHWPoison(page))
> - return true;
> - else if (PageHuge(page) && PageHWPoison(compound_head(page)))
> - return true;
> -
> - return false;
> -}
> -
> extern unsigned long highest_memmap_pfn;
>
> /*
> --
> 2.30.2
>
--
Sincerely yours,
Mike.
next prev parent reply other threads:[~2021-05-02 6:32 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-29 12:25 [PATCH v1 0/7] fs/proc/kcore: don't read offline sections, logically offline pages and hwpoisoned pages David Hildenbrand
2021-04-29 12:25 ` [PATCH v1 1/7] fs/proc/kcore: drop KCORE_REMAP and KCORE_OTHER David Hildenbrand
2021-05-02 6:31 ` Mike Rapoport
2021-04-29 12:25 ` [PATCH v1 2/7] fs/proc/kcore: pfn_is_ram check only applies to KCORE_RAM David Hildenbrand
2021-05-02 6:31 ` Mike Rapoport
2021-04-29 12:25 ` [PATCH v1 3/7] mm: rename and move page_is_poisoned() David Hildenbrand
2021-05-02 6:32 ` Mike Rapoport [this message]
2021-05-05 13:13 ` Michal Hocko
2021-05-05 13:17 ` David Hildenbrand
2021-05-05 13:27 ` Michal Hocko
2021-05-05 13:39 ` David Hildenbrand
2021-05-05 13:45 ` Michal Hocko
2021-05-06 1:08 ` Aili Yao
2021-05-06 0:56 ` Aili Yao
2021-05-06 7:06 ` Michal Hocko
2021-05-06 7:28 ` Aili Yao
2021-05-06 7:55 ` Michal Hocko
2021-05-06 8:52 ` Aili Yao
2021-04-29 12:25 ` [PATCH v1 4/7] fs/proc/kcore: don't read offline sections, logically offline pages and hwpoisoned pages David Hildenbrand
2021-05-02 6:32 ` Mike Rapoport
2021-04-29 12:25 ` [PATCH v1 5/7] mm: introduce page_offline_(begin|end|freeze|unfreeze) to synchronize setting PageOffline() David Hildenbrand
2021-05-02 6:33 ` Mike Rapoport
2021-05-03 8:11 ` David Hildenbrand
2021-05-05 13:24 ` Michal Hocko
2021-05-05 15:10 ` David Hildenbrand
2021-05-05 17:41 ` Mike Rapoport
2021-04-29 12:25 ` [PATCH v1 6/7] virtio-mem: use page_offline_(start|end) when " David Hildenbrand
2021-05-02 6:33 ` Mike Rapoport
2021-05-03 8:16 ` David Hildenbrand
2021-05-03 8:23 ` Michael S. Tsirkin
2021-04-29 12:25 ` [PATCH v1 7/7] fs/proc/kcore: use page_offline_(freeze|unfreeze) David Hildenbrand
2021-05-02 6:34 ` Mike Rapoport
2021-05-03 8:28 ` David Hildenbrand
2021-05-03 9:28 ` Mike Rapoport
2021-05-03 10:13 ` David Hildenbrand
2021-05-03 11:33 ` Mike Rapoport
2021-05-03 11:35 ` David Hildenbrand
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