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

[Andrew Morton]

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?

> Signed-off-by: Bernd Edlinger <bernd.edlinger@xxxxxxxxxx>

Was a -stable backport considered?