Re: [PATCH v3] proc: Ensure we see the exit of each process tid exactly
From: Eric W. Biederman
Date: Mon Apr 27 2020 - 16:27:18 EST
ebiederm@xxxxxxxxxxxx (Eric W. Biederman) writes:
> Take a good look over the code base and see if I can see any more
> issues like was found in next_tgid and repost the core patches.
Oleg,
I am reading through kernel/ptrace.c and I am seeing a lot of:
spin_lock(&child->sighand->siglock);
In places where I don't see anything guaranteeing the child is stopped
such as ptrace_freeze_traced. Are all of those places safe or
do some of the need to be transformed into lock_task_sighand in
case the process is current running?
I might just be reading the code to quickly and missing what keeps the
code from executing exec and changing sighand.
Eric