Re: Fork issue on W10 WOW

[Corinna Vinschen <corinna-cygwin@cygwin.com>]

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On Jul 12 12:31, marco atzeri wrote:
> On Tue, Jul 10, 2018 at 7:33 AM, Marco Atzeri  wrote:
> > Am 09.07.2018 um 14:37 schrieb Corinna Vinschen:
> >
> >
> > It seems there is some type of ASLR for the wow64.
> > I will try to rebase using 0x6b000000 to see if
> > make any change
> >
> 
> from my experiments the 32bit under W10 is substantially unusable.
> At every restart the base address of the wow64*.dll are moved
> randomly everywhere between  0x50000000 and 0x70000000.

Actually, as I wrote before, in my case the wow64 stuff is beyond
0x70000000:

76E90000-76F08000 /mnt/c/Windows/System32/wow64win.dll
76F10000-76F62000 /mnt/c/Windows/System32/wow64.dll
76F70000-76F7A000 /mnt/c/Windows/System32/wow64cpu.dll

> It seems the 32bit subsystem is totally ignoring that cygwin programs
> have not the ASLR flag. May be the subsystem base address
> is initialized before any cygwin program is started.

The ASLRed addresses of system DLLs are puzzled out at system boottime,
afaik.

> It seems I have only two choices:
> - disable totally ASLR, but some guidance (1)  around seem not working anymore

That won't work.  You can't disable ASLR for system DLLs.

> - use a virtual machine for a 32 bit W7 system to be used as build environment.

You could reboot the machine until the DLLs are at an adddress you
can work with and then never reboot again.  /duck/


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat

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