From: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
To: "'David Gibson'" <david@gibson.dropbear.id.au>,
<linux-ia64@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: RE: IA64 non-contiguous memory space bugs
Date: Tue, 21 Feb 2006 18:53:32 -0800 [thread overview]
Message-ID: <200602220253.k1M2rWg10346@unix-os.sc.intel.com> (raw)
In-Reply-To: <20060222001359.GA23574@localhost.localdomain>
David Gibson wrote on Tuesday, February 21, 2006 4:14 PM
> First bug (confirmed many months ago by Chris Wedgwood) - you can get
> weird effects if you attempt to mmap() something into one of the
> address space gaps. The ia64 outer wrapper for mmap2() tries to
> prevent it, but doesn't do a good enough job, it's still possible
> indirectly with shmat() and maybe mremap(). Basic trouble is that
> most of the checks applied by the generic code assume that everything
> between 0 and TASK_SIZE is valid.
Ha ha ha.
On ia64, the low level tlb fault handler (vhpt_miss and nested_dtlb_miss)
checks that all unused address bits (between REGION_NUMBER and PGDIR_SHIFT)
should be all zero. If they are not zero, it will fall into page fault
handler and in there, ia64 should just send SEGV instead of happily hand
over a page. Buggy buggy....
- Ken
next prev parent reply other threads:[~2006-02-22 2:53 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-02-22 0:13 IA64 non-contiguous memory space bugs David Gibson
2006-02-22 0:39 ` David S. Miller
2006-02-22 2:17 ` David Gibson
2006-02-22 1:31 ` Chen, Kenneth W
2006-02-22 1:51 ` Chen, Kenneth W
2006-02-22 2:25 ` 'David Gibson'
2006-02-22 2:45 ` Chen, Kenneth W
2006-02-22 16:35 ` Hugh Dickins
2006-02-22 23:49 ` 'David Gibson'
2006-02-23 20:13 ` Hugh Dickins
2006-02-24 0:11 ` 'David Gibson'
2006-02-24 1:14 ` Chen, Kenneth W
2006-02-24 2:46 ` 'David Gibson'
2006-02-22 2:15 ` 'David Gibson'
2006-02-22 2:53 ` Chen, Kenneth W [this message]
2006-02-22 3:55 ` David Mosberger-Tang
2006-02-22 4:02 ` David Gibson
2006-02-22 16:19 ` Chen, Kenneth W
2006-02-22 23:26 ` 'David Gibson'
2006-02-22 3:01 Zhang, Yanmin
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