Re: [PATCHv8] exec: Fix dead-lock in de_thread with ptrace_attach

[Eric W. Biederman]

Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> writes:

> On Thu, 10 Jun 2021 09:31:42 +0200 Bernd Edlinger <bernd.edlinger@xxxxxxxxxx> wrote:
>
>> This introduces signal->unsafe_execve_in_progress,
>> which is used to fix the case when at least one of the
>> sibling threads is traced, and therefore the trace
>> process may dead-lock in ptrace_attach, but de_thread
>> will need to wait for the tracer to continue execution.
>
> Deadlocks are serious.  Is this exploitable by unprivileged userspace?

The processes are killable so I don't think this is the serious in the
way you mean.  In fact Linus has already said that it is not a deadlock.

Eric