On Fri, 26 Jan 2018, Jiri Kosina wrote:
> > diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h
> > index 34f053a150a9..091f53fe31cc 100644
> > --- a/include/linux/thread_info.h
> > +++ b/include/linux/thread_info.h
> > @@ -43,7 +43,9 @@ enum {
> > #define THREAD_ALIGN THREAD_SIZE
> > #endif
> >
> > -#if IS_ENABLED(CONFIG_DEBUG_STACK_USAGE) ||
> > IS_ENABLED(CONFIG_DEBUG_KMEMLEAK)
> > +#if IS_ENABLED(CONFIG_DEBUG_STACK_USAGE) || \
> > + IS_ENABLED(CONFIG_DEBUG_KMEMLEAK) || \
> > + IS_ENABLED(CONFIG_CLEAR_STACK_FORK)
> > # define THREADINFO_GFP (GFP_KERNEL_ACCOUNT | __GFP_ZERO)
> > #else
> > # define THREADINFO_GFP (GFP_KERNEL_ACCOUNT)
> > diff --git a/kernel/fork.c b/kernel/fork.c
> > index 2295fc69717f..215b1ce2b2cd 100644
> > --- a/kernel/fork.c
> > +++ b/kernel/fork.c
> > @@ -215,7 +215,7 @@ static unsigned long *alloc_thread_stack_node(struct
> > task_struct *tsk, int node)
> > if (!s)
> > continue;
> >
> > -#ifdef CONFIG_DEBUG_KMEMLEAK
> > +#if IS_ENABLED(CONFIG_DEBUG_KMEMLEAK) ||
> > IS_ENABLED(CONFIG_CLEAR_STACK_FORK)
> > /* Clear stale pointers from reused stack. */
> > memset(s->addr, 0, THREAD_SIZE);
> > #endif
>
> Is there any good reason not to do it symmetricaly also for non-vmapped
> stacks? (by passing __GFP_ZERO to alloc_pages_node())?
Ah, of course you already do by extending THREADINFO_GFP, sorry for the
noise.
--
Jiri Kosina
