Re: exec hang at boot.

[Almudena Garcia]

After testing "upstream" and Debian's GNU Mach over my Thinkpad machines (T60, R60e and T410), the exec problem seems to have disappeared.

To be sure, I go to repeat the test adding some long code to delay the booting.

El jue., 8 oct. 2020 a las 13:11, Almudena Garcia (<liberamenso10000@gmail.com>) escribió:

I can test It over real hardware, in which usually we can see more problems than in a virtual scenery. When I finish the test, I will report the results here.

In Qemu, the boot looks fine, and the exec problems seem to have disappeared. I tested It using gnumach in SMP mode (--enable-cpus=2).

El jue., 8 oct. 2020 a las 0:17, Samuel Thibault (<samuel.thibault@gnu.org>) escribió:

Hello,

I might have found the trigger for the exec hang at boot. The symptoms
were that very early during the program loading by ld.so, it would
overflow its stack with 0x40, apparently because there were odd things
happening with the GOT. One odd thing was that ld.so was getting loaded
at 0x0. That's because it is a PIE. Issues that might come up are that
pointer 0x0 could then actually be a should-be-valid pointer...  I
modified gnumach to load PIE binaries at 0x8000000, like our exec server
does, and couldn't reproduce the exec hang at boot. This is now in
debian as gnumach version 2:1.8+git20201007-1.

Samuel