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Date: Mon, 10 Mar 2014 10:49:39 -0700
From: "H. Peter Anvin" <hpa@linux.intel.com>
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To: Andy Lutomirski <luto@amacapital.net>
CC: Linus Torvalds <torvalds@linux-foundation.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Stefani Seibold <stefani@seibold.net>,
        Andreas Brief <Andreas.Brief@rohde-schwarz.com>,
        Martin Runge <Martin.Runge@rohde-schwarz.com>
Subject: Re: [x86, vdso] BUG: unable to handle kernel paging request at d34bd000
References: <20140307013833.GD8427@localhost> <1394176888.1018.3.camel@wall-e.seibold.net> <CALCETrVCwZWvd78urw+O4zD3PoNZTQxg8FMzTrUi4+5w9rC5=A@mail.gmail.com> <1394229220.20013.13.camel@wall-e.seibold.net> <CALCETrXB0G3aA1Usp4U-9-eN0z22YC4Sn+3z42mrU2ab0gE9gQ@mail.gmail.com> <1394354848.1002.37.camel@wall-e.seibold.net> <531D044C.2090303@linux.intel.com> <CALCETrXJobOnVB-ne9s57o3Z1KwK4fRtaYi8W=L4+UT065fKJw@mail.gmail.com> <CALCETrUyJWQnQsX22+wrvPbXkj67nhZ0SMP1_hCo2yZ+Z5tMyA@mail.gmail.com> <531DD35A.5060202@linux.intel.com> <CA+55aFwKpBybz9S9A=+tcr1BbdzAbagL30Br2cak2GrdPH=hhA@mail.gmail.com> <CALCETrW6CT2ceHiHzMaZUGkwEBFWQEemFS5Fj=V7Wg-cNArMLg@mail.gmail.com> <531DF549.2090403@linux.intel.com> <CALCETrV+3yCfOCJzRKN-woOyp2RF_=dW1V=9CwpYTUNGAiLoNQ@mail.gmail.com> <531DF896.8010305@linux.intel.com> <CALCETrVKfBpVHZcyccWRYM4rdOAETSQsxjiQuxn+0AeX78XiEw@mail.gmail.com>
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On 03/10/2014 10:46 AM, Andy Lutomirski wrote:
> 
> It might be nice in general for there to be a /dev/vdso and for the
> vdso to literally be a mapping of that device node.  I bet that CRIU
> would appreciate this.  (The mmap flags would be a little odd, since
> different pages have different protections.)
> 

Actually, it presumably ought to be handled like any other (readonly)
ELF file: that is, let the mapper handle the permissions.

	-hpa