From: Oleg Nesterov <oleg@redhat.com>
To: Jim Newsome <jnewsome@torproject.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ptrace: Allow other threads to access tracee
Date: Thu, 11 Mar 2021 16:21:23 +0100 [thread overview]
Message-ID: <20210311152123.GC15552@redhat.com> (raw)
In-Reply-To: <20210310205908.23447-1-jnewsome@torproject.org>
On 03/10, Jim Newsome wrote:
>
> @@ -238,7 +238,7 @@ static int ptrace_check_attach(struct task_struct *child, bool ignore_state)
> * be changed by us so it's not changing right after this.
> */
> read_lock(&tasklist_lock);
> - if (child->ptrace && child->parent == current) {
> + if (child->ptrace && same_thread_group(child->parent, current)) {
Cough... it is not that simple.
Just suppose that 2 threads call ptrace(tracee) at the same time. Say, the 1st
thread does PTRACE_CONT while the 2nd thread tries to change the registers.
Oleg.
next prev parent reply other threads:[~2021-03-11 15:22 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-10 20:59 [PATCH] ptrace: Allow other threads to access tracee Jim Newsome
2021-03-11 1:31 ` kernel test robot
2021-03-11 1:31 ` kernel test robot
2021-03-11 15:21 ` Oleg Nesterov [this message]
2021-03-11 16:49 ` Jim Newsome
2021-03-12 17:07 ` Oleg Nesterov
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