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.
The first patch adds a canary to init_task's end of stack. While the second patch provides a helper to determine the integrity of the canary. The third checks for a stack overrun and takes appropriate action since the damage is already done, there is no point in continuing. Changes since v1: * Rebased against v3.17-rc4 * Add a canary to init_task - Oleg Nesterov * Fix various code formatting issues - Peter Zijlstra * Introduce Kconfig option - Peter Zijlstra Aaron Tomlin (3): init/main.c: Give init_task a canary sched: Add helper for task stack page overrun checking sched: BUG when stack end location is over written arch/powerpc/mm/fault.c | 5 +---- arch/x86/mm/fault.c | 5 +---- include/linux/sched.h | 4 ++++ init/main.c | 1 + kernel/fork.c | 12 +++++++++--- kernel/sched/core.c | 4 ++++ kernel/trace/trace_stack.c | 4 +--- lib/Kconfig.debug | 12 ++++++++++++ 8 files changed, 33 insertions(+), 14 deletions(-) -- 1.9.3 _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
