How investigate segfault in proot?

[Samuel Martin]

Hi all,

I have a weird issue with proot, and I don't know how investigate it:
when I run a command within proot 5.1.0 and the exact same
chroot/stage3, it runs fine on some hosts, but segfault on others.

The OK hosts are a Debian Jessie with a kernel 3.16.0 or an Archlinux
with a kernel 4.0.7.
The culprit host is a Ubuntu 14.04 LTS with a kernel 3.16.0.

Here are 2 logs, a success one [1] and a failure one [2], trying to
execute a simple 'echo hello'.

TIA,
BR,

[1] http://code.bulix.org/fxuuxm-88843
[2] http://code.bulix.org/b4k094-88844

--
Samuel

[Cedric]

On Tue, Sep 01, 2015 at 03:26:22PM +0200, Samuel Martin wrote:
> Hi all,
>
> I have a weird issue with proot, and I don't know how investigate it:
> when I run a command within proot 5.1.0 and the exact same
> chroot/stage3, it runs fine on some hosts, but segfault on others.

I think it is due to PRoot's loader; it assumes position-independant
programs can always be loaded at a hard-coded base address [1], but
this might conflit with some kernels. There was an attempt to fix
this issue [2], but it was not completed. May I recommend you
versions 4.x of PRoot instead?

[1] https://github.com/proot-me/PRoot/blob/v5.1.0/src/arch.h#L83
[2] https://github.com/proot-me/PRoot/tree/position_independant

> Here are 2 logs, a success one [1] and a failure one [2], trying to
> execute a simple 'echo hello'.
>
> TIA,
> BR,
>
> [1] http://code.bulix.org/fxuuxm-88843
> [2] http://code.bulix.org/b4k094-88844

I get "Database connection error."

Cédric.