This check is turning up a lot of code paths which need to be fixed so while those paths are fixed, let's make this check optional so that folks can still use lockdep.
CC: Tejun Heo <[email protected]> CC: Jeff Layton <[email protected]> CC: "Myklebust, Trond" <[email protected]> CC: Oleg Nesterov <[email protected]> CC: Ming Lei <[email protected]> CC: "Rafael J. Wysocki" <[email protected]> CC: Andrew Morton <[email protected]> CC: Ingo Molnar <[email protected]> --- include/linux/freezer.h | 2 ++ lib/Kconfig.debug | 12 ++++++++++++ 2 files changed, 14 insertions(+) diff --git a/include/linux/freezer.h b/include/linux/freezer.h index 043a5cf..03bdc54 100644 --- a/include/linux/freezer.h +++ b/include/linux/freezer.h @@ -49,8 +49,10 @@ extern void thaw_kernel_threads(void); static inline bool try_to_freeze(void) { +#ifdef CONFIG_DEBUG_LOCK_HELD_FREEZING if (!(current->flags & PF_NOFREEZE)) debug_check_no_locks_held(); +#endif might_sleep(); if (likely(!freezing(current))) return false; diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 28be08c..bddda5f 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -547,6 +547,18 @@ config DEBUG_MUTEXES This feature allows mutex semantics violations to be detected and reported. +config DEBUG_LOCK_HELD_FREEZING + bool "Lock debugging: detect when locks are held during freeze" + depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT + select DEBUG_SPINLOCK + select DEBUG_MUTEXES + select LOCKDEP + help + This feature will check whether any lock is incorrectly held + while freezing. If a task freezes with a lock held it will + block any other task that is waiting on that lock from freezing. + In the case of cgroup_freezer, this can cause a deadlock. + config DEBUG_LOCK_ALLOC bool "Lock debugging: detect incorrect freeing of live locks" depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT -- 1.7.12.4 -- 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/
