Commit-ID: 0d9e26329b0c9263d4d9e0422d80a0e73268c52f Gitweb: http://git.kernel.org/tip/0d9e26329b0c9263d4d9e0422d80a0e73268c52f Author: Aaron Tomlin <[email protected]> AuthorDate: Fri, 12 Sep 2014 14:16:19 +0100 Committer: Ingo Molnar <[email protected]> CommitDate: Fri, 19 Sep 2014 12:35:24 +0200
sched: Add default-disabled option to BUG() when stack end location is overwritten 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 <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: Alexei Starovoitov <[email protected]> Cc: Al Viro <[email protected]> Cc: Andi Kleen <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Dan Streetman <[email protected]> Cc: Davidlohr Bueso <[email protected]> Cc: David S. Miller <[email protected]> Cc: Kees Cook <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Lubomir Rintel <[email protected]> Cc: Paul E. McKenney <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> --- 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 4b1ddeb..61ee2b3 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2693,6 +2693,9 @@ 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 /* * Test if we are atomic. Since do_exit() needs to call into * schedule() atomically, we ignore that path. Otherwise whine diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index a285900..e58163d 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -824,6 +824,18 @@ config SCHEDSTATS application, you can say N to avoid the very slight overhead this adds. +config SCHED_STACK_END_CHECK + bool "Detect stack corruption on calls to schedule()" + depends on DEBUG_KERNEL + default n + help + This option checks for a stack overrun on calls to schedule(). + If the stack end location is found to be over written always panic as + the content of the corrupted region can no longer be trusted. + This is to ensure no erroneous behaviour occurs which could result in + data corruption or a sporadic crash at a later stage once the region + is examined. The runtime overhead introduced is minimal. + config TIMER_STATS bool "Collect kernel timers statistics" depends on DEBUG_KERNEL && PROC_FS -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
