From: Ralf Baechle <ralf@linux-mips.org>
To: David Daney <ddaney.cavm@gmail.com>
Cc: linux-mips@linux-mips.org, David Daney <david.daney@cavium.com>,
stable@vger.kernel.org
Subject: Re: [PATCH] MIPS: Fix page table corruption on THP permission changes.
Date: Tue, 5 Jul 2016 17:10:26 +0200 [thread overview]
Message-ID: <20160705151026.GN7075@linux-mips.org> (raw)
In-Reply-To: <1466117431-18020-1-git-send-email-ddaney.cavm@gmail.com>
On Thu, Jun 16, 2016 at 03:50:31PM -0700, David Daney wrote:
> From: David Daney <david.daney@cavium.com>
>
> When the core THP code is modifying the permissions of a huge page it
> calls pmd_modify(), which unfortunately was clearing the _PAGE_HUGE bit
> of the page table entry. The result can be kernel messages like:
>
> mm/memory.c:397: bad pmd 000000040080004d.
> mm/memory.c:397: bad pmd 00000003ff00004d.
> mm/memory.c:397: bad pmd 000000040100004d.
>
> or:
>
> ------------[ cut here ]------------
> WARNING: at mm/mmap.c:3200 exit_mmap+0x150/0x158()
> Modules linked in: ipv6 at24 octeon3_ethernet octeon_srio_nexus m25p80
> CPU: 12 PID: 1295 Comm: pmderr Not tainted 3.10.87-rt80-Cavium-Octeon #4
> Stack : 0000000040808000 0000000014009ce1 0000000000400004 ffffffff81076ba0
> 0000000000000000 0000000000000000 ffffffff85110000 0000000000000119
> 0000000000000004 0000000000000000 0000000000000119 43617669756d2d4f
> 0000000000000000 ffffffff850fda40 ffffffff85110000 0000000000000000
> 0000000000000000 0000000000000009 ffffffff809207a0 0000000000000c80
> ffffffff80f1bf20 0000000000000001 000000ffeca36828 0000000000000001
> 0000000000000000 0000000000000001 000000ffeca7e700 ffffffff80886924
> 80000003fd7a0000 80000003fd7a39b0 80000003fdea8000 ffffffff80885780
> 80000003fdea8000 ffffffff80f12218 000000000000000c 000000000000050f
> 0000000000000000 ffffffff80865c4c 0000000000000000 0000000000000000
> ...
> Call Trace:
> [<ffffffff80865c4c>] show_stack+0x6c/0xf8
> [<ffffffff80885780>] warn_slowpath_common+0x78/0xa8
> [<ffffffff809207a0>] exit_mmap+0x150/0x158
> [<ffffffff80882d44>] mmput+0x5c/0x110
> [<ffffffff8088b450>] do_exit+0x230/0xa68
> [<ffffffff8088be34>] do_group_exit+0x54/0x1d0
> [<ffffffff8088bfc0>] __wake_up_parent+0x0/0x18
>
> ---[ end trace c7b38293191c57dc ]---
> BUG: Bad rss-counter state mm:80000003fa168000 idx:1 val:1536
>
> Fix by not clearing _PAGE_HUGE bit.
I resolved the conflict with my recent other fix for pmd_modify
and just applied and pushed this.
Ralf
next prev parent reply other threads:[~2016-07-05 15:10 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-16 22:50 [PATCH] MIPS: Fix page table corruption on THP permission changes David Daney
2016-06-17 12:00 ` Aaro Koskinen
2016-06-17 12:00 ` Aaro Koskinen
2016-06-17 16:22 ` David Daney
2016-06-17 16:22 ` David Daney
2016-06-23 12:09 ` Aaro Koskinen
2016-06-23 12:09 ` Aaro Koskinen
2016-07-05 15:10 ` Ralf Baechle [this message]
2016-08-16 8:11 ` Joshua Kinard
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