From 3117df0453828bd045c16244e6f50e5714667a8a Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Wed, 13 Dec 2006 00:34:43 -0800 Subject: [PATCH] [PATCH] lockdep: print irq-trace info on asserts 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/lockdep.h | 16 +++++++++++++--- kernel/lockdep.c | 6 +----- kernel/sched.c | 4 ++++ 3 files changed, 18 insertions(+), 8 deletions(-) diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index 498bfbd3b4e1..ea097dddc44f 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -281,15 +281,25 @@ 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 /* diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 69e92c6b0472..07a3d74a84be 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -1447,7 +1447,7 @@ check_usage_backwards(struct task_struct *curr, struct held_lock *this, 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); @@ -1460,10 +1460,6 @@ static inline void print_irqtrace_events(struct task_struct *curr) print_ip_sym(curr->softirq_disable_ip); } -#else -static inline void print_irqtrace_events(struct task_struct *curr) -{ -} #endif static int diff --git a/kernel/sched.c b/kernel/sched.c index 8a0afb97af71..5cd833bc2173 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -3429,6 +3429,8 @@ 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)); @@ -6977,6 +6979,8 @@ 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