From: Michal Hocko <mhocko@kernel.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
Roland McGrath <roland@hack.frob.com>,
Andreas Schwab <schwab@suse.com>,
William Preston <wpreston@suse.com>
Subject: Re: [PATCH v2] kernel/fork: fix CLONE_CHILD_CLEARTID regression in nscd
Date: Wed, 24 Aug 2016 10:10:24 +0200 [thread overview]
Message-ID: <20160824081023.GE31179@dhcp22.suse.cz> (raw)
In-Reply-To: <20160823163233.GA7123@redhat.com>
On Tue 23-08-16 18:32:34, Oleg Nesterov wrote:
> On 08/23, Michal Hocko wrote:
> >
> > --- a/kernel/fork.c
> > +++ b/kernel/fork.c
> > @@ -913,14 +913,11 @@ void mm_release(struct task_struct *tsk, struct mm_struct *mm)
> > deactivate_mm(tsk, mm);
> >
> > /*
> > - * If we're exiting normally, clear a user-space tid field if
> > - * requested. We leave this alone when dying by signal, to leave
> > - * the value intact in a core dump, and to save the unnecessary
> > - * trouble, say, a killed vfork parent shouldn't touch this mm.
> > - * Userland only wants this done for a sys_exit.
> > + * Signal userspace if we're not exiting with a core dump
> > + * or a killed vfork parent which shouldn't touch this mm.
>
> Well. ACK, but the comment looks wrong...
>
> The "killed vfork parent ..." part should be removed, as you pointed
> out this is no longer true.
>
> OTOH, to me it would be better to not remove the "leave the value
> intact in a core dump" part, otherwise the " we're not exiting with
> a core dump" looks pointless because SIGNAL_GROUP_COREDUMP is self-
> documenting.
Sounds better?
diff --git a/kernel/fork.c b/kernel/fork.c
index b89f0eb99f0a..ddde5849df81 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -914,7 +914,8 @@ void mm_release(struct task_struct *tsk, struct mm_struct *mm)
/*
* Signal userspace if we're not exiting with a core dump
- * or a killed vfork parent which shouldn't touch this mm.
+ * because we want to leave the value intact for debugging
+ * purposes.
*/
if (tsk->clear_child_tid) {
if (!(tsk->signal->flags & SIGNAL_GROUP_COREDUMP) &&
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2016-08-24 8:10 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-23 16:12 [PATCH v2] kernel/fork: fix CLONE_CHILD_CLEARTID regression in nscd Michal Hocko
2016-08-23 16:32 ` Oleg Nesterov
2016-08-24 8:10 ` Michal Hocko [this message]
2016-08-24 15:32 ` Oleg Nesterov
2016-08-24 15:37 ` Michal Hocko
2016-08-31 6:42 ` Michal Hocko
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