From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031922AbWLGJui (ORCPT ); Thu, 7 Dec 2006 04:50:38 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1031923AbWLGJui (ORCPT ); Thu, 7 Dec 2006 04:50:38 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:46507 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031922AbWLGJuh (ORCPT ); Thu, 7 Dec 2006 04:50:37 -0500 Date: Thu, 7 Dec 2006 10:49:43 +0100 From: Ingo Molnar To: Andrew Morton Cc: linux-kernel@vger.kernel.org Subject: [patch] lockdep: print irq-trace info on asserts Message-ID: <20061207094943.GA4719@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.4.2.2i X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -5.9 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-5.9 required=5.9 tests=ALL_TRUSTED,BAYES_00 autolearn=no SpamAssassin version=3.0.3 -3.3 ALL_TRUSTED Did not pass through any untrusted hosts -2.6 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Subject: [patch] lockdep: print irq-trace info on asserts From: Ingo Molnar when we print an assert due to scheduling-in-atomic bugs, and if lockdep is enabled, then the IRQ tracing information of lockdep can be printed to pinpoint the code location that disabled interrupts. This saved me quite a bit of debugging time in cases where the backtrace did not identify the irq-disabling site well enough. Signed-off-by: Ingo Molnar --- include/linux/lockdep.h | 16 +++++++++++++--- kernel/lockdep.c | 6 +----- kernel/sched.c | 4 ++++ 3 files changed, 18 insertions(+), 8 deletions(-) Index: linux/include/linux/lockdep.h =================================================================== --- linux.orig/include/linux/lockdep.h +++ linux/include/linux/lockdep.h @@ -282,15 +282,25 @@ struct lock_class_key { }; #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_GENERIC_HARDIRQS) extern void early_init_irq_lock_class(void); #else -# define early_init_irq_lock_class() do { } while (0) +static inline void early_init_irq_lock_class(void) +{ +} #endif #ifdef CONFIG_TRACE_IRQFLAGS extern void early_boot_irqs_off(void); extern void early_boot_irqs_on(void); +extern void print_irqtrace_events(struct task_struct *curr); #else -# define early_boot_irqs_off() do { } while (0) -# define early_boot_irqs_on() do { } while (0) +static inline void early_boot_irqs_off(void) +{ +} +static inline void early_boot_irqs_on(void) +{ +} +static inline void print_irqtrace_events(struct task_struct *curr) +{ +} #endif /* Index: linux/kernel/lockdep.c =================================================================== --- linux.orig/kernel/lockdep.c +++ linux/kernel/lockdep.c @@ -1449,7 +1449,7 @@ check_usage_backwards(struct task_struct return print_irq_inversion_bug(curr, backwards_match, this, 0, irqclass); } -static inline void print_irqtrace_events(struct task_struct *curr) +void print_irqtrace_events(struct task_struct *curr) { printk("irq event stamp: %u\n", curr->irq_events); printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event); @@ -1462,10 +1462,6 @@ static inline void print_irqtrace_events print_ip_sym(curr->softirq_disable_ip); } -#else -static inline void print_irqtrace_events(struct task_struct *curr) -{ -} #endif static int Index: linux/kernel/sched.c =================================================================== --- linux.orig/kernel/sched.c +++ linux/kernel/sched.c @@ -3353,6 +3353,8 @@ asmlinkage void __sched schedule(void) "%s/0x%08x/%d\n", current->comm, preempt_count(), current->pid); debug_show_held_locks(current); + if (irqs_disabled()) + print_irqtrace_events(current); dump_stack(); } profile_hit(SCHED_PROFILING, __builtin_return_address(0)); @@ -6895,6 +6897,8 @@ void __might_sleep(char *file, int line) printk("in_atomic():%d, irqs_disabled():%d\n", in_atomic(), irqs_disabled()); debug_show_held_locks(current); + if (irqs_disabled()) + print_irqtrace_events(current); dump_stack(); } #endif