Re: mm: NULL ptr deref in balance_dirty_pages_ratelimited

2014-02-26 Thread Peter Zijlstra
On Wed, Feb 26, 2014 at 05:20:51PM +0200, Kirill A. Shutemov wrote: > On Wed, Feb 26, 2014 at 10:48:30PM +0800, Bob Liu wrote: > > > Do you relay on unlock_page() to have a compiler barrier? > > > > > > > Before your commit mapping is a local variable and be assigned before > > unlock_page(): > >

Re: mm: NULL ptr deref in balance_dirty_pages_ratelimited

2014-02-26 Thread Paul E. McKenney
On Wed, Feb 26, 2014 at 05:20:51PM +0200, Kirill A. Shutemov wrote: > On Wed, Feb 26, 2014 at 10:48:30PM +0800, Bob Liu wrote: > > > Do you relay on unlock_page() to have a compiler barrier? > > > > > > > Before your commit mapping is a local variable and be assigned before > > unlock_page(): > >

Re: mm: NULL ptr deref in balance_dirty_pages_ratelimited

2014-02-26 Thread Kirill A. Shutemov
On Wed, Feb 26, 2014 at 10:48:30PM +0800, Bob Liu wrote: > > Do you relay on unlock_page() to have a compiler barrier? > > > > Before your commit mapping is a local variable and be assigned before > unlock_page(): > struct address_space *mapping = page->mapping; > unlock_page(dirty_page); > put_pa

Re: mm: NULL ptr deref in balance_dirty_pages_ratelimited

2014-02-26 Thread Bob Liu
On Wed, Feb 26, 2014 at 10:09 PM, Kirill A. Shutemov wrote: > On Wed, Feb 26, 2014 at 03:15:07PM +0800, Bob Liu wrote: >> On Wed, Feb 26, 2014 at 3:32 AM, Sasha Levin wrote: >> > Hi all, >> > >> > While fuzzing with trinity inside a KVM tools running latest -next kernel >> > I've stumbled on the

Re: mm: NULL ptr deref in balance_dirty_pages_ratelimited

2014-02-26 Thread Kirill A. Shutemov
On Wed, Feb 26, 2014 at 03:15:07PM +0800, Bob Liu wrote: > On Wed, Feb 26, 2014 at 3:32 AM, Sasha Levin wrote: > > Hi all, > > > > While fuzzing with trinity inside a KVM tools running latest -next kernel > > I've stumbled on the following spew: > > > > [ 232.869443] BUG: unable to handle kernel

Re: mm: NULL ptr deref in balance_dirty_pages_ratelimited

2014-02-25 Thread Bob Liu
On Wed, Feb 26, 2014 at 3:32 AM, Sasha Levin wrote: > Hi all, > > While fuzzing with trinity inside a KVM tools running latest -next kernel > I've stumbled on the following spew: > > [ 232.869443] BUG: unable to handle kernel NULL pointer dereference at > 0020 > [ 232.870230] IP: []

mm: NULL ptr deref in balance_dirty_pages_ratelimited

2014-02-25 Thread Sasha Levin
Hi all, While fuzzing with trinity inside a KVM tools running latest -next kernel I've stumbled on the following spew: [ 232.869443] BUG: unable to handle kernel NULL pointer dereference at 0020 [ 232.870230] IP: [] balance_dirty_pages_ratelimited+0x1e/0x150 [ 232.870230] PGD