Re: [PATCH] ptrace: restore smp_rmb() in __ptrace_may_access()

From: Eric W. Biederman
Date: Wed May 29 2019 - 21:45:34 EST


Jann Horn <jannh@xxxxxxxxxx> writes:

> I'm actually trying to get rid of the ->mm access in
> __ptrace_may_access() entirely by moving the dumpability and the
> user_ns into the signal_struct, but I don't have patches for that
> ready (yet).

Do you have a plan for dealing with old linux-threads style threads
where you have two processes that share the same mm, but have different
signal_structs.

I don't think it is required to share any other structures except
mm_struct when you share mm_struct. Maybe sighand_struct.

Not to derail your idea. Only needing to look at signal_struct sounds
very nice. I just know we have some other somewhat bizarre cases the
kernel still supports.

Eric