On Thu, Sep 04, 2014 at 03:50:24PM +0100, Aaron Tomlin wrote:
quoted hunk ↗ jump to hunk
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 <redacted>
---
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?