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From: Andrew Morton <akpm@linux-foundation.org>
To: David Rientjes <rientjes@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
	linux-kernel@vger.kernel.org, Jan Kara <jack@suse.cz>,
	Davide Libenzi <davidel@xmailserver.org>
Subject: Re: [patch] fs, epoll: short circuit fetching events if thread has been killed
Date: Tue, 9 May 2017 16:05:20 -0700	[thread overview]
Message-ID: <20170509160520.a394a93544419eb53d2d0879@linux-foundation.org> (raw)
In-Reply-To: <alpine.DEB.2.10.1705031722350.76784@chino.kir.corp.google.com>

On Wed, 3 May 2017 17:22:53 -0700 (PDT) David Rientjes <rientjes@google.com> wrote:

> We've encountered zombies that are waiting for a thread to exit that are
> looping in ep_poll() almost endlessly although there is a pending SIGKILL
> as a result of a group exit.
> 
> This happens because we always find ep_events_available() and fetch more
> events and never are able to check for signal_pending() that would break
> from the loop and return -EINTR.
> 
> Special case fatal signals and break immediately to guarantee that we
> loop to fetch more events and delay making a timely exit.
> 
> It would also be possible to simply move the check for signal_pending()
> higher than checking for ep_events_available(), but there have been no
> reports of delayed signal handling other than SIGKILL preventing zombies
> from exiting that would be fixed by this.

Any thoughts on the priority of this?  -stable?  If so, why?

  reply	other threads:[~2017-05-09 23:05 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-04  0:22 David Rientjes
2017-05-09 23:05 ` Andrew Morton [this message]
2017-05-10  0:08   ` David Rientjes
2017-05-10 13:07 ` Michal Hocko

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