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] Modul
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 = 00
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
> [ 74.67419
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: [] wake_futex
ux.intel.com;
> mi...@kernel.org; linux-ker...@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:
>
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
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-
ux.intel.com;
> mi...@kernel.org; linux-ker...@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 p
