Re: Worth using personality(ADDR_NO_RANDOMIZE) for EXEC_BACKEND on linux?

Hi,

On 2021-08-09 13:43:03 -0400, Robert Haas wrote:
> On Mon, Aug 9, 2021 at 1:30 PM Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> wrote:
> > How common is to get a failure? I know I've run tests under
> > EXEC_BACKEND and not seen any failures. Not many runs though.

I get check-world failures in about 1/2-1/3 of the runs, and a plain check
fails in maybe 1/4 of the cases. It's pretty annoying because it often isn't
trivial to distinguish whether I've broken something or whether it's
randomization related...

The frequency of failures isn't stable over time, making it a bit harder to
know what's going on.

> On macOS, failures are extremely common. Sometimes I have to run
> simple tests many times to get even one success. The proposal on the
> table won't help with that problem since it's Linux-specific, but if
> there's any way to do something similar on macOS it would be a _huge_
> help.

There does seem to be a way of doing so, because I found blog posts talking
about how to get e.g. lldb to *enable* ASLR, which it disables by default...

Greetings,

Andres Freund