On Wed 16-07-14 17:36:49, David Rientjes wrote: > Setting vm_dirty_bytes and dirty_background_bytes is not protected by any > serialization. > > Therefore, it's possible for either variable to change value after the > test in global_dirty_limits() to determine whether available_memory needs > to be initialized or not. > > Always ensure that available_memory is properly initialized. > > Cc: [email protected] > Signed-off-by: David Rientjes <[email protected]>
Makes sense to me Acked-by: Michal Hocko <[email protected]> > --- > mm/page-writeback.c | 5 +---- > 1 file changed, 1 insertion(+), 4 deletions(-) > > diff --git a/mm/page-writeback.c b/mm/page-writeback.c > --- a/mm/page-writeback.c > +++ b/mm/page-writeback.c > @@ -261,14 +261,11 @@ static unsigned long global_dirtyable_memory(void) > */ > void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty) > { > + const unsigned long available_memory = global_dirtyable_memory(); > unsigned long background; > unsigned long dirty; > - unsigned long uninitialized_var(available_memory); > struct task_struct *tsk; > > - if (!vm_dirty_bytes || !dirty_background_bytes) > - available_memory = global_dirtyable_memory(); > - > if (vm_dirty_bytes) > dirty = DIV_ROUND_UP(vm_dirty_bytes, PAGE_SIZE); > else -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
