From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: aarcange@redhat.com, linux-mm@kvack.org, paulus@samba.org,
linuxppc-dev@lists.ozlabs.org, kirill.shutemov@linux.intel.com
Subject: Re: [PATCH V4] powerpc: thp: Fix crash on mremap
Date: Mon, 13 Jan 2014 18:32:54 +0200 [thread overview]
Message-ID: <20140113163254.GA4658@node.dhcp.inet.fi> (raw)
In-Reply-To: <1389593064-32664-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com>
On Mon, Jan 13, 2014 at 11:34:24AM +0530, Aneesh Kumar K.V wrote:
> From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
>
> This patch fix the below crash
>
> NIP [c00000000004cee4] .__hash_page_thp+0x2a4/0x440
> LR [c0000000000439ac] .hash_page+0x18c/0x5e0
> ...
> Call Trace:
> [c000000736103c40] [00001ffffb000000] 0x1ffffb000000(unreliable)
> [437908.479693] [c000000736103d50] [c0000000000439ac] .hash_page+0x18c/0x5e0
> [437908.479699] [c000000736103e30] [c00000000000924c] .do_hash_page+0x4c/0x58
>
> On ppc64 we use the pgtable for storing the hpte slot information and
> store address to the pgtable at a constant offset (PTRS_PER_PMD) from
> pmd. On mremap, when we switch the pmd, we need to withdraw and deposit
> the pgtable again, so that we find the pgtable at PTRS_PER_PMD offset
> from new pmd.
>
> We also want to move the withdraw and deposit before the set_pmd so
> that, when page fault find the pmd as trans huge we can be sure that
> pgtable can be located at the offset.
>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
--
Kirill A. Shutemov
prev parent reply other threads:[~2014-01-13 16:33 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-13 6:04 [PATCH V4] powerpc: thp: Fix crash on mremap Aneesh Kumar K.V
2014-01-13 7:36 ` Benjamin Herrenschmidt
2014-01-13 9:46 ` Aneesh Kumar K.V
2014-01-13 13:37 ` Benjamin Herrenschmidt
2014-01-13 16:32 ` Kirill A. Shutemov [this message]
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