Messages in this thread | | | Date | Fri, 26 Jan 2018 23:01:21 +0100 (CET) | From | Jiri Kosina <> | Subject | Re: [PATCH] fork: Allow stack to be wiped on fork |
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On Tue, 16 Jan 2018, Kees Cook 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())?
Thanks,
-- Jiri Kosina SUSE Labs
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