From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga01.intel.com ([192.55.52.88]:38929 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933740AbbENC0x (ORCPT ); Wed, 13 May 2015 22:26:53 -0400 Message-ID: <55555909.7050805@intel.com> Date: Fri, 15 May 2015 10:25:13 +0800 From: Pan Xinhui MIME-Version: 1.0 To: Greg KH CC: stable@vger.kernel.org Subject: Re: [PATCH] kernel/smp.c: fix a panic as cp->info is used wrongly and a list corruption References: <55531348.1080902@intel.com> <20150512121459.GB25401@kroah.com> In-Reply-To: <20150512121459.GB25401@kroah.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: hi,Greg thanks for your kind reply :) I will send out patch V2 later. let me do some explanation here first. this feature which I am working on is reverted totally by commit fc21c0 in upstream, maybe the author notice the code is buggy. So I just fix it, not revert this feature here, big change is not accepted in stable kernel tree. thanks again for your help. thanks xinhui On 2015年05月12日 20:14, Greg KH wrote: > On Wed, May 13, 2015 at 05:03:04PM +0800, Pan Xinhui wrote: >> this patch reverts commit 3440a1ca99707f093e9568ba9762764d3162dd8f which causes the regression. >> >> base knowledge: kernel call cp->func using cp->info as its argument. like cp->func(cp->info); >> >> current code is totally wrong, as 1) &softirq is at stack. 2) cp->info don't point to struct call_single_data. >> So in remote_softirq_receive, >> 1) If the caller had left __try_remote_softirq, dereferencing cp->info could not fetch the correct value. >> 2) And we can't get struct call_single_data *cp anymore. >> >> The list corruption is below. >> __local_trigger will add cp->list into softirq_work_list. But no one will delete cp->list on behalf of us. >> if we can succeed to raise_softirq_irqoff, we must delete it from softirq_work_list. because we has lost control of pointer cp. >> cp is passed in and may be freed later in other places. >> >> Cc: # 3.10 >> Signed-off-by: xinhuix.pan >> --- >> include/linux/smp.h | 1 + >> kernel/softirq.c | 10 +++++++--- >> 2 files changed, 8 insertions(+), 3 deletions(-) > > > > This is not the correct way to submit patches for inclusion in the > stable kernel tree. Please read Documentation/stable_kernel_rules.txt > for how to do this properly. > > >