From: Dan Williams <dan.j.williams@intel.com>
To: Jan Kara <jack@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Linux MM <linux-mm@kvack.org>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
Chandan Rajendra <chandan@linux.ibm.com>,
stable <stable@vger.kernel.org>
Subject: Re: [PATCH] mm: Fix modifying of page protection by insert_pfn()
Date: Mon, 11 Mar 2019 10:22:44 -0700 [thread overview]
Message-ID: <CAPcyv4gBhTXs3Lf1ESgtaT4JUV8xiwNnM_OQU3-0ENB0hpAPng@mail.gmail.com> (raw)
In-Reply-To: <20190311084537.16029-1-jack@suse.cz>
On Mon, Mar 11, 2019 at 1:45 AM Jan Kara <jack@suse.cz> wrote:
>
> Aneesh has reported that PPC triggers the following warning when
> excercising DAX code:
>
> [c00000000007610c] set_pte_at+0x3c/0x190
> LR [c000000000378628] insert_pfn+0x208/0x280
> Call Trace:
> [c0000002125df980] [8000000000000104] 0x8000000000000104 (unreliable)
> [c0000002125df9c0] [c000000000378488] insert_pfn+0x68/0x280
> [c0000002125dfa30] [c0000000004a5494] dax_iomap_pte_fault.isra.7+0x734/0xa40
> [c0000002125dfb50] [c000000000627250] __xfs_filemap_fault+0x280/0x2d0
> [c0000002125dfbb0] [c000000000373abc] do_wp_page+0x48c/0xa40
> [c0000002125dfc00] [c000000000379170] __handle_mm_fault+0x8d0/0x1fd0
> [c0000002125dfd00] [c00000000037a9b0] handle_mm_fault+0x140/0x250
> [c0000002125dfd40] [c000000000074bb0] __do_page_fault+0x300/0xd60
> [c0000002125dfe20] [c00000000000acf4] handle_page_fault+0x18
>
> Now that is WARN_ON in set_pte_at which is
>
> VM_WARN_ON(pte_hw_valid(*ptep) && !pte_protnone(*ptep));
>
> The problem is that on some architectures set_pte_at() cannot cope with
> a situation where there is already some (different) valid entry present.
>
> Use ptep_set_access_flags() instead to modify the pfn which is built to
> deal with modifying existing PTE.
>
> CC: stable@vger.kernel.org
> Fixes: b2770da64254 "mm: add vm_insert_mixed_mkwrite()"
> Reported-by: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
> Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Andrew, can you pick this up?
next prev parent reply other threads:[~2019-03-11 17:22 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-11 8:45 Jan Kara
2019-03-11 11:59 ` Aneesh Kumar K.V
2019-03-11 17:22 ` Dan Williams [this message]
2019-03-27 17:33 ` Jan Kara
2019-03-27 21:14 ` Andrew Morton
2019-03-28 3:18 ` Aneesh Kumar K.V
2019-03-28 9:02 ` Jan Kara
2019-03-28 9:02 ` Jan Kara
2019-03-25 0:38 ` Sasha Levin
2019-03-25 17:02 ` Jan Kara
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