From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753124Ab3ILGtK (ORCPT ); Thu, 12 Sep 2013 02:49:10 -0400 Received: from e31.co.us.ibm.com ([32.97.110.149]:56605 "EHLO e31.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751346Ab3ILGtI (ORCPT ); Thu, 12 Sep 2013 02:49:08 -0400 Date: Thu, 12 Sep 2013 12:19:00 +0530 From: Srikar Dronamraju To: Oleg Nesterov Cc: Ingo Molnar , anton@redhat.com, Hemant Kumar Shaw , masami.hiramatsu.pt@hitachi.com, Mikhail Kulemin , systemtap@sourceware.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] uprobes: Fix utask->depth accounting in handle_trampoline() Message-ID: <20130912064859.GA26737@linux.vnet.ibm.com> Reply-To: Srikar Dronamraju References: <20130911154726.GA8093@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20130911154726.GA8093@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13091206-8236-0000-0000-000001AFA5D7 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Oleg Nesterov [2013-09-11 17:47:26]: > Currently utask->depth is simply the number of allocated/pending > return_instance's in uprobe_task->return_instances list. > > handle_trampoline() should decrement this counter every time we > handle/free an instance, but due to typo it does this only if > ->chained == T. This means that in the likely case this counter > is never decremented and the probed task can't report more than > MAX_URETPROBE_DEPTH events. > > Cc: stable@vger.kernel.org > Signed-off-by: Oleg Nesterov > Reported-by: Mikhail Kulemin > Reported-by: Hemant Kumar Shaw Acked-by: Srikar Dronamraju Mikhail Kulemin has verified that this fix works for him. > --- > kernel/events/uprobes.c | 4 +--- > 1 files changed, 1 insertions(+), 3 deletions(-) > > diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c > index f356974..ad8e1bd 100644 > --- a/kernel/events/uprobes.c > +++ b/kernel/events/uprobes.c > @@ -1682,12 +1682,10 @@ static bool handle_trampoline(struct pt_regs *regs) > tmp = ri; > ri = ri->next; > kfree(tmp); > + utask->depth--; > > if (!chained) > break; > - > - utask->depth--; > - > BUG_ON(!ri); > } > > -- > 1.5.5.1 > > -- Thanks and Regards Srikar Dronamraju