Re: [PATCH V2 1/2] exec: don't wait for zombie threads with cred_guard_mutex held

From: Oleg Nesterov
Date: Mon Feb 20 2017 - 10:38:09 EST

On 02/20, Oleg Nesterov wrote:
> Again, this needs some work. For example check_unsafe_exec() assumes
> it can't race with another thread, see 9e00cdb091b008cb3c78192651180
> "exec:check_unsafe_exec: kill the dead -EAGAIN and clear_in_exec logic".
> But this looks solvable.

Forgot to mention... plus check_unsafe_exec() checks ptrace, this is
another reason why we can't simply shift mutex_lock(cred_guard_mutex)