On Thu, Sep 04, 2014 at 03:50:24PM +0100, Aaron Tomlin wrote:
> Currently in the event of a stack overrun a call to schedule()
> does not check for this type of corruption. This corruption is
> often silent and can go unnoticed. However once the corrupted
> region is examined at a later stage, the outcome is undefined
> and often results in a sporadic page fault which cannot be
> handled.
>
> This patch checks for a stack overrun and takes appropriate
> action since the damage is already done, there is no point
> in continuing.
>
> Signed-off-by: Aaron Tomlin <atom...@redhat.com>
> ---
> kernel/sched/core.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index ec1a286..d6af6a0 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -2660,6 +2660,9 @@ static noinline void __schedule_bug(struct task_struct
> *prev)
> */
> static inline void schedule_debug(struct task_struct *prev)
> {
> + if (unlikely(prev != &init_task &&
> + task_stack_end_corrupted(prev)))
> + BUG();
superfluous linebreak, also we appear to have BUG_ON() for situations
just like these.
secondly, while I appreciate the 'feature' you're making schedule()
slower for everybody, what do you propose to do about that?
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