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From: Ivan Delalande <colona@arista.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Dmitry Safonov <0x7f454c46@gmail.com>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	Andy Lutomirski <luto@kernel.org>
Subject: Re: [PATCH v2] exec: don't force_sigsegv processes with a pending fatal signal
Date: Mon, 11 Feb 2019 15:20:42 -0800
Message-ID: <20190211232042.GA18232@visor> (raw)
In-Reply-To: <20190211171252.GE21430@redhat.com>

On Mon, Feb 11, 2019 at 06:12:53PM +0100, Oleg Nesterov wrote:
> sorry, I couldn't look at this patch before.
> 
> On 02/04, Ivan Delalande wrote:
> >
> > --- a/fs/exec.c
> > +++ b/fs/exec.c
> > @@ -1660,7 +1660,12 @@ int search_binary_handler(struct linux_binprm *bprm)
> >  		if (retval < 0 && !bprm->mm) {
> >  			/* we got to flush_old_exec() and failed after it */
> >  			read_unlock(&binfmt_lock);
> > -			force_sigsegv(SIGSEGV, current);
> > +			if (!fatal_signal_pending(current)) {
> > +				if (print_fatal_signals)
> > +					pr_info("load_binary() failed: %d\n",
> > +						retval);
> 
> I won't argue, but do we really want this spam?
> 
> > +				force_sigsegv(SIGSEGV, current);
> > +			}
> >  			return retval;
> >  		}
> >  		if (retval != -ENOEXEC || !bprm->file) {
> > diff --git a/kernel/signal.c b/kernel/signal.c
> > index e1d7ad8e6ab1..674076e63624 100644
> > --- a/kernel/signal.c
> > +++ b/kernel/signal.c
> > @@ -2552,10 +2552,10 @@ static void signal_delivered(struct ksignal *ksig, int stepping)
> >
> >  void signal_setup_done(int failed, struct ksignal *ksig, int stepping)
> >  {
> > -	if (failed)
> > -		force_sigsegv(ksig->sig, current);
> > -	else
> > +	if (!failed)
> >  		signal_delivered(ksig, stepping);
> > +	else if (!fatal_signal_pending(current))
> > +		force_sigsegv(ksig->sig, current);
> 
> The changelog doesn't explain this change.
> 
> OK, I guess it comes from the previous discussion, setup_rt_frame() can equally fail
> if fatal_signal_pending(). But this should be documented at least in the changelog,
> and I still think we could simply change force_sigsegv() instead.
> 
> In any case, Eric has already mentioned that we going to give SIGKILL more priority,
> so I think we can drop this patch?

Yes, I've been running our tests on top of Eric's tree over the week-end
and haven't seen any new hit. I also see that Andrew has dropped the
patch from -mm, so no futher action should be required here.

Thank you for taking a look at the patch anyway.

-- 
Ivan Delalande
Arista Networks

      reply index

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-05  2:53 Ivan Delalande
2019-02-05 21:11 ` Andrew Morton
2019-02-06  3:10   ` Ivan Delalande
2019-02-08  5:13     ` ebiederm
2019-02-09  0:16       ` Ivan Delalande
2019-02-10 17:05         ` ebiederm
2019-02-11 23:25           ` Ivan Delalande
2019-02-11 16:02         ` Oleg Nesterov
2019-02-11 17:12 ` Oleg Nesterov
2019-02-11 23:20   ` Ivan Delalande [this message]

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