On Fri, Sep 12, 2014 at 04:04:51PM +1000, Michael Ellerman wrote:
On Thu, 2014-09-11 at 16:41 +0100, Aaron Tomlin wrote:
quoted
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 +++
lib/Kconfig.debug | 12 ++++++++++++
2 files changed, 15 insertions(+)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index ec1a286..0b70b73 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)
{
+#ifdef CONFIG_SCHED_STACK_END_CHECK
+ BUG_ON(unlikely(task_stack_end_corrupted(prev)))
+#endif
Spot the bug? Please compile your code in future.
Oops! Sorry about that.
--
Aaron Tomlin