RE: Add memory barrier when waiting on futex

2013-11-26 Thread Ma, Xindong
ux.intel.com; > mi...@kernel.org; linux-kernel@vger.kernel.org; gre...@linuxfoundation.org; > Tu, Xiaobing > Subject: Re: Add memory barrier when waiting on futex > > On Tue, Nov 26, 2013 at 01:07:25AM +, Ma, Xindong wrote: > > I've already aware that they've prot

Re: Add memory barrier when waiting on futex

2013-11-26 Thread Peter Zijlstra
On Tue, Nov 26, 2013 at 01:07:25AM +, Ma, Xindong wrote: > [ 1038.694701] putmetho-11202 1...1 1035007289001: futex_wait: LEON, wait > ==, addr:41300384, pid:11202 > [ 1038.694716] putmetho-11202 1...1 1035007308860: futex_wait_queue_me: > LEON, q->task => 11202 > [ 1038.694731]

Re: Add memory barrier when waiting on futex

2013-11-26 Thread Peter Zijlstra
On Tue, Nov 26, 2013 at 01:07:25AM +, Ma, Xindong wrote: > I've already aware that they've protected by spinlock, this is why I adding a > memory barrier to fix it. That doesn't make sense.. the spinlocks should provide the required serialization, there's nothing to fix. > I reproduced this

Re: Add memory barrier when waiting on futex

2013-11-26 Thread Peter Zijlstra
On Tue, Nov 26, 2013 at 01:07:25AM +, Ma, Xindong wrote: I've already aware that they've protected by spinlock, this is why I adding a memory barrier to fix it. That doesn't make sense.. the spinlocks should provide the required serialization, there's nothing to fix. I reproduced this

Re: Add memory barrier when waiting on futex

2013-11-26 Thread Peter Zijlstra
On Tue, Nov 26, 2013 at 01:07:25AM +, Ma, Xindong wrote: [ 1038.694701] putmetho-11202 1...1 1035007289001: futex_wait: LEON, wait ==, addr:41300384, pid:11202 [ 1038.694716] putmetho-11202 1...1 1035007308860: futex_wait_queue_me: LEON, q-task = 11202 [ 1038.694731] SharedPr-11272

RE: Add memory barrier when waiting on futex

2013-11-26 Thread Ma, Xindong
...@kernel.org; linux-kernel@vger.kernel.org; gre...@linuxfoundation.org; Tu, Xiaobing Subject: Re: Add memory barrier when waiting on futex On Tue, Nov 26, 2013 at 01:07:25AM +, Ma, Xindong wrote: I've already aware that they've protected by spinlock, this is why I adding a memory barrier

RE: Add memory barrier when waiting on futex

2013-11-25 Thread Ma, Xindong
ux.intel.com; > mi...@kernel.org; linux-kernel@vger.kernel.org; gre...@linuxfoundation.org; > Tu, Xiaobing > Subject: Re: Add memory barrier when waiting on futex > > On Mon, Nov 25, 2013 at 01:15:17PM +, Ma, Xindong wrote: > > We encountered following panic several times: >

Re: Add memory barrier when waiting on futex

2013-11-25 Thread Darren Hart
On Mon, 2013-11-25 at 15:39 +0100, Peter Zijlstra wrote: > On Mon, Nov 25, 2013 at 01:15:17PM +, Ma, Xindong wrote: > > We encountered following panic several times: > > > [ 74.671982] BUG: unable to handle kernel NULL pointer dereference at > > 0008 > > [ 74.672101] IP: []

Re: Add memory barrier when waiting on futex

2013-11-25 Thread Peter Zijlstra
On Mon, Nov 25, 2013 at 01:15:17PM +, Ma, Xindong wrote: > We encountered following panic several times: > [ 74.671982] BUG: unable to handle kernel NULL pointer dereference at > 0008 > [ 74.672101] IP: [] wake_futex+0x47/0x80 > [ 74.674144] [] futex_wake+0xc9/0x110 > [

Re: Add memory barrier when waiting on futex

2013-11-25 Thread gre...@linuxfoundation.org
On Mon, Nov 25, 2013 at 01:15:17PM +, Ma, Xindong wrote: > We encountered following panic several times: > [ 74.671982] BUG: unable to handle kernel NULL pointer dereference at > 0008 > [ 74.672101] IP: [] wake_futex+0x47/0x80 > [ 74.672185] *pdpt = 10108001 *pde =

Add memory barrier when waiting on futex

2013-11-25 Thread Ma, Xindong
We encountered following panic several times: [ 74.671982] BUG: unable to handle kernel NULL pointer dereference at 0008 [ 74.672101] IP: [] wake_futex+0x47/0x80 [ 74.672185] *pdpt = 10108001 *pde = [ 74.672278] Oops: 0002 [#1] PREEMPT SMP [ 74.672403]

Add memory barrier when waiting on futex

2013-11-25 Thread Ma, Xindong
We encountered following panic several times: [ 74.671982] BUG: unable to handle kernel NULL pointer dereference at 0008 [ 74.672101] IP: [c129bb27] wake_futex+0x47/0x80 [ 74.672185] *pdpt = 10108001 *pde = [ 74.672278] Oops: 0002 [#1] PREEMPT SMP [

Re: Add memory barrier when waiting on futex

2013-11-25 Thread gre...@linuxfoundation.org
On Mon, Nov 25, 2013 at 01:15:17PM +, Ma, Xindong wrote: We encountered following panic several times: [ 74.671982] BUG: unable to handle kernel NULL pointer dereference at 0008 [ 74.672101] IP: [c129bb27] wake_futex+0x47/0x80 [ 74.672185] *pdpt = 10108001 *pde =

Re: Add memory barrier when waiting on futex

2013-11-25 Thread Peter Zijlstra
On Mon, Nov 25, 2013 at 01:15:17PM +, Ma, Xindong wrote: We encountered following panic several times: [ 74.671982] BUG: unable to handle kernel NULL pointer dereference at 0008 [ 74.672101] IP: [c129bb27] wake_futex+0x47/0x80 [ 74.674144] [c129bc29] futex_wake+0xc9/0x110 [

Re: Add memory barrier when waiting on futex

2013-11-25 Thread Darren Hart
On Mon, 2013-11-25 at 15:39 +0100, Peter Zijlstra wrote: On Mon, Nov 25, 2013 at 01:15:17PM +, Ma, Xindong wrote: We encountered following panic several times: [ 74.671982] BUG: unable to handle kernel NULL pointer dereference at 0008 [ 74.672101] IP: [c129bb27]

RE: Add memory barrier when waiting on futex

2013-11-25 Thread Ma, Xindong
...@kernel.org; linux-kernel@vger.kernel.org; gre...@linuxfoundation.org; Tu, Xiaobing Subject: Re: Add memory barrier when waiting on futex On Mon, Nov 25, 2013 at 01:15:17PM +, Ma, Xindong wrote: We encountered following panic several times: [ 74.671982] BUG: unable to handle kernel NULL