Re: [PATCH v2] um: Avoid longjmp/setjmp symbol clashes with libpthread.a

From	Florian Fainelli <f.fainelli@gmail.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v2] um: Avoid longjmp/setjmp symbol clashes with libpthread.a
Date	2017-06-02 07:50 +0200
Message-ID	<tNNDc-4UD-9@gated-at.bofh.it> (permalink)
References	(7 earlier) <tNFcB-7FC-1@gated-at.bofh.it> <tNFcB-7FC-5@gated-at.bofh.it> <tNFmi-7IJ-9@gated-at.bofh.it> <tNFmi-7IJ-7@gated-at.bofh.it> <tNFPj-87Q-1@gated-at.bofh.it>
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On 06/01/2017 02:25 PM, Thomas Meyer wrote:
> Am Donnerstag, den 01.06.2017, 22:58 +0200 schrieb Richard Weinberger:
>>
>> Sorry, I thought you are CC'ed.
>> Thomas please speak up. AFAIR UML fails to boot on one of your new
>> Laptops.
> 
> Hi,
> 
> yes, the first userspace process failes here:
> 
> void userspace(struct uml_pt_regs *regs)
> {
>         int err, status, op, pid = userspace_pid[0];
>         /* To prevent races if using_sysemu changes under us.*/
>         int local_using_sysemu;
>         siginfo_t si;
> 
>         /* Handle any immediate reschedules or signals */
>         interrupt_end();
> 
>         while (1) {
> 
>                 /*
>                  * This can legitimately fail if the process loads a
>                  * bogus value into a segment register.  It will
>                  * segfault and PTRACE_GETREGS will read that value
>                  * out of the process.  However, PTRACE_SETREGS will
>                  * fail.  In this case, there is nothing to do but
>                  * just kill the process.
>                  */
>                 if (ptrace(PTRACE_SETREGS, pid, 0, regs->gp))
>                         fatal_sigsegv();
> 
>                 if (put_fp_registers(pid, regs->fp))
> ->                        fatal_sigsegv();
> 
> the put_fp_registers fails with errno 4 if I recall correctly.
> 
> I didn't investigate yet further, why the the xstate ptrace call fails.

Which of the branches is put_fp_registers() taking? The
restore_fpx_registers() or restore_fp_registers()? 4 would be EINTR...
What kernel version is used on your host running the UML binary?

Thanks
-- 
Florian

Thread

Re: [PATCH v2] um: Avoid longjmp/setjmp symbol clashes with  libpthread.a Florian Fainelli <f.fainelli@gmail.com> - 2017-06-01 21:40 +0200
  Re: [PATCH v2] um: Avoid longjmp/setjmp symbol clashes with  libpthread.a Florian Fainelli <f.fainelli@gmail.com> - 2017-06-01 22:20 +0200
    Re: [PATCH v2] um: Avoid longjmp/setjmp symbol clashes with  libpthread.a Richard Weinberger <richard@nod.at> - 2017-06-01 22:20 +0200
      Re: [PATCH v2] um: Avoid longjmp/setjmp symbol clashes with  libpthread.a Florian Fainelli <f.fainelli@gmail.com> - 2017-06-01 22:50 +0200
        Re: [PATCH v2] um: Avoid longjmp/setjmp symbol clashes with  libpthread.a Richard Weinberger <richard@nod.at> - 2017-06-01 22:50 +0200
          Re: [PATCH v2] um: Avoid longjmp/setjmp symbol clashes with  libpthread.a Richard Weinberger <richard@nod.at> - 2017-06-01 23:00 +0200
            Re: [PATCH v2] um: Avoid longjmp/setjmp symbol clashes with  libpthread.a Thomas Meyer <thomas@m3y3r.de> - 2017-06-01 23:30 +0200
              Re: [PATCH v2] um: Avoid longjmp/setjmp symbol clashes with  libpthread.a Florian Fainelli <f.fainelli@gmail.com> - 2017-06-02 07:50 +0200
                Re: [PATCH v2] um: Avoid longjmp/setjmp symbol clashes with  libpthread.a Richard Weinberger <richard@nod.at> - 2017-06-02 09:40 +0200
                Re: [PATCH v2] um: Avoid longjmp/setjmp symbol clashes with  libpthread.a Thomas Meyer <thomas@m3y3r.de> - 2017-06-03 23:30 +0200
                Re: [PATCH v2] um: Avoid longjmp/setjmp symbol clashes with  libpthread.a Richard Weinberger <richard@nod.at> - 2017-06-03 23:40 +0200
                Re: [PATCH v2] um: Avoid longjmp/setjmp symbol clashes with  libpthread.a Thomas Meyer <thomas@m3y3r.de> - 2017-06-02 10:10 +0200
                Re: [PATCH v2] um: Avoid longjmp/setjmp symbol clashes with  libpthread.a Richard Weinberger <richard@nod.at> - 2017-06-02 10:40 +0200
                Re: [PATCH v2] um: Avoid longjmp/setjmp symbol clashes with  libpthread.a Thomas Meyer <thomas@m3y3r.de> - 2017-06-02 11:20 +0200
                Re: [PATCH v2] um: Avoid longjmp/setjmp symbol clashes with  libpthread.a Thomas Meyer <thomas@m3y3r.de> - 2017-06-02 15:20 +0200
          Re: [PATCH v2] um: Avoid longjmp/setjmp symbol clashes with  libpthread.a Florian Fainelli <f.fainelli@gmail.com> - 2017-06-01 23:00 +0200
  Re: [PATCH v2] um: Avoid longjmp/setjmp symbol clashes with  libpthread.a Richard Weinberger <richard@nod.at> - 2017-06-01 22:20 +0200

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