From: Oleg Nesterov <oleg@redhat.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
strace-devel@lists.sourceforge.net,
Mike Galbraith <umgwanakikbuti@gmail.com>,
Aleksa Sarai <asarai@suse.com>
Subject: Re: strace lockup when tracing exec in go
Date: Fri, 23 Sep 2016 12:21:41 +0200 [thread overview]
Message-ID: <20160923102141.GA16189@redhat.com> (raw)
In-Reply-To: <20160922135301.GF11875@dhcp22.suse.cz>
On 09/22, Michal Hocko wrote:
>
> --- a/kernel/signal.c
> +++ b/kernel/signal.c
> @@ -91,6 +91,10 @@ static int sig_ignored(struct task_struct *t, int sig, bool force)
> if (!sig_task_ignored(t, sig, force))
> return 0;
>
> + /* Do not ignore signals sent from child to the parent */
> + if (current->ptrace && current->parent == t)
> + return 0;
This doesn't look right in general, and this can't really help.
This assumes that the tracer will call do_wait() after mm_access()
fails, but this is not necessarily true.
Note also ptrace_attach(), -ERESTARTNOINTR means that the tracer won't
even return to user-space if SIGCHLD is ignored, the tracer will silently
restart the syscall.
Oleg.
next prev parent reply other threads:[~2016-09-23 10:22 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-21 15:29 strace lockup when tracing exec in go Michal Hocko
2016-09-22 4:15 ` Mike Galbraith
2016-09-22 8:01 ` Michal Hocko
2016-09-22 8:20 ` Aleksa Sarai
2016-09-22 8:36 ` Michal Hocko
2016-09-22 9:40 ` Mike Galbraith
2016-09-22 9:53 ` Michal Hocko
2016-09-22 10:09 ` Mike Galbraith
2016-09-22 11:09 ` Michal Hocko
2016-09-22 13:53 ` Michal Hocko
2016-09-23 1:17 ` Aleksa Sarai
2016-09-23 10:21 ` Oleg Nesterov [this message]
2016-09-23 11:18 ` Michal Hocko
2016-09-23 13:21 ` Oleg Nesterov
2016-09-23 13:40 ` Michal Hocko
2016-09-23 14:07 ` Oleg Nesterov
2016-09-23 14:19 ` Michal Hocko
2016-09-23 9:50 ` Oleg Nesterov
2016-09-23 11:23 ` Michal Hocko
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20160923102141.GA16189@redhat.com \
--to=oleg@redhat.com \
--cc=asarai@suse.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mhocko@kernel.org \
--cc=strace-devel@lists.sourceforge.net \
--cc=umgwanakikbuti@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).