From: Fengguang Wu <fengguang.wu@intel.com>
To: lkp@lists.01.org
Subject: Re: [percpu] BUG: unable to handle kernel NULL pointer dereference at (null)
Date: Thu, 04 Sep 2014 20:38:45 +0800 [thread overview]
Message-ID: <20140904123845.GA19925@localhost> (raw)
In-Reply-To: <20140902171657.GG5001@linux.vnet.ibm.com>
[-- Attachment #1: Type: text/plain, Size: 894 bytes --]
On Tue, Sep 02, 2014 at 10:16:57AM -0700, Paul E. McKenney wrote:
> On Tue, Sep 02, 2014 at 11:55:58AM -0500, Christoph Lameter wrote:
> > On Tue, 2 Sep 2014, Paul E. McKenney wrote:
> >
> > > Added by ac1bea85781e (sched,rcu: Make cond_resched() report RCU quiescent
> > > states), removed by 4a81e8328d379 (rcu: Reduce overhead of cond_resched()
> > > checks for RCU). So, as you say, no effect on contemporary kernels.
> >
> > Well not sure what to make out of all of this....
>
> Yep, still confused as to how the patch adding the definition could have
> caused a failure. Fengguang, any thoughts?
Yeah this is confusing.. I checked carefully and find that commit
0e98023 and afea227 are built on 2 quite different servers -- which
might generate slightly different code. I'll fix this issue and make
the build server selection more consistent.
Thanks,
Fengguang
WARNING: multiple messages have this Message-ID (diff)
From: Fengguang Wu <fengguang.wu@intel.com>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Christoph Lameter <cl@linux.com>, Jet Chen <jet.chen@intel.com>,
Su Tao <tao.su@intel.com>, Yuanhan Liu <yuanhan.liu@intel.com>,
LKP <lkp@01.org>,
linux-kernel@vger.kernel.org
Subject: Re: [percpu] BUG: unable to handle kernel NULL pointer dereference at (null)
Date: Thu, 4 Sep 2014 20:38:45 +0800 [thread overview]
Message-ID: <20140904123845.GA19925@localhost> (raw)
In-Reply-To: <20140902171657.GG5001@linux.vnet.ibm.com>
On Tue, Sep 02, 2014 at 10:16:57AM -0700, Paul E. McKenney wrote:
> On Tue, Sep 02, 2014 at 11:55:58AM -0500, Christoph Lameter wrote:
> > On Tue, 2 Sep 2014, Paul E. McKenney wrote:
> >
> > > Added by ac1bea85781e (sched,rcu: Make cond_resched() report RCU quiescent
> > > states), removed by 4a81e8328d379 (rcu: Reduce overhead of cond_resched()
> > > checks for RCU). So, as you say, no effect on contemporary kernels.
> >
> > Well not sure what to make out of all of this....
>
> Yep, still confused as to how the patch adding the definition could have
> caused a failure. Fengguang, any thoughts?
Yeah this is confusing.. I checked carefully and find that commit
0e98023 and afea227 are built on 2 quite different servers -- which
might generate slightly different code. I'll fix this issue and make
the build server selection more consistent.
Thanks,
Fengguang
next prev parent reply other threads:[~2014-09-04 12:38 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-02 4:58 [percpu] BUG: unable to handle kernel NULL pointer dereference at (null) Fengguang Wu
2014-09-02 4:58 ` Fengguang Wu
2014-09-02 15:34 ` Paul E. McKenney
2014-09-02 15:34 ` Paul E. McKenney
2014-09-02 16:00 ` Christoph Lameter
2014-09-02 16:00 ` Christoph Lameter
2014-09-02 16:21 ` Paul E. McKenney
2014-09-02 16:21 ` Paul E. McKenney
2014-09-02 16:55 ` Christoph Lameter
2014-09-02 16:55 ` Christoph Lameter
2014-09-02 17:16 ` Paul E. McKenney
2014-09-02 17:16 ` Paul E. McKenney
2014-09-04 12:38 ` Fengguang Wu [this message]
2014-09-04 12:38 ` Fengguang Wu
2014-09-04 16:04 ` Paul E. McKenney
2014-09-04 16:04 ` Paul E. McKenney
2014-09-13 12:41 ` Fengguang Wu
2014-09-13 12:41 ` Fengguang Wu
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