Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-pb0-f53.google.com ([209.85.160.53]:48310 "EHLO mail-pb0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754493Ab3CFAa0 (ORCPT ); Tue, 5 Mar 2013 19:30:26 -0500 From: Mandeep Singh Baines To: linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org Cc: Mandeep Singh Baines , Tejun Heo , Jeff Layton , "Myklebust, Trond" , Oleg Nesterov , Ming Lei , "Rafael J. Wysocki" , Andrew Morton , Ingo Molnar Subject: [PATCH] lockdep: make lock held while freezing check optional Date: Tue, 5 Mar 2013 16:30:19 -0800 Message-Id: <1362529819-19076-1-git-send-email-msb@chromium.org> In-Reply-To: <20130305231110.GK15816@fieldses.org> References: <20130305231110.GK15816@fieldses.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: 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 CC: Jeff Layton CC: "Myklebust, Trond" CC: Oleg Nesterov CC: Ming Lei CC: "Rafael J. Wysocki" CC: Andrew Morton CC: Ingo Molnar --- 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