diff options
| -rw-r--r-- | include/linux/ftrace.h | 7 | ||||
| -rw-r--r-- | include/linux/init_task.h | 1 | ||||
| -rw-r--r-- | include/linux/sched.h | 4 | ||||
| -rw-r--r-- | kernel/trace/ring_buffer.c | 42 |
4 files changed, 53 insertions, 1 deletions
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 97c83e1..39b95c5 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -488,8 +488,15 @@ static inline int test_tsk_trace_graph(struct task_struct *tsk) extern int ftrace_dump_on_oops; +#ifdef CONFIG_PREEMPT +#define INIT_TRACE_RECURSION .trace_recursion = 0, +#endif + #endif /* CONFIG_TRACING */ +#ifndef INIT_TRACE_RECURSION +#define INIT_TRACE_RECURSION +#endif #ifdef CONFIG_HW_BRANCH_TRACER diff --git a/include/linux/init_task.h b/include/linux/init_task.h index dcfb933..6fc2185 100644 --- a/include/linux/init_task.h +++ b/include/linux/init_task.h @@ -187,6 +187,7 @@ extern struct cred init_cred; INIT_TRACE_IRQFLAGS \ INIT_LOCKDEP \ INIT_FTRACE_GRAPH \ + INIT_TRACE_RECURSION \ } diff --git a/include/linux/sched.h b/include/linux/sched.h index b4c38bc..7ede5e4 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1428,7 +1428,9 @@ struct task_struct { #ifdef CONFIG_TRACING /* state flags for use by tracers */ unsigned long trace; -#endif + /* bitmask of trace recursion */ + unsigned long trace_recursion; +#endif /* CONFIG_TRACING */ }; /* Future-safe accessor for struct task_struct's cpus_allowed. */ diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 84a6055..b421b0e 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1481,6 +1481,40 @@ rb_reserve_next_event(struct ring_buffer_per_cpu *cpu_buffer, return event; } +static int trace_irq_level(void) +{ + return hardirq_count() + softirq_count() + in_nmi(); +} + +static int trace_recursive_lock(void) +{ + int level; + + level = trace_irq_level(); + + if (unlikely(current->trace_recursion & (1 << level))) { + /* Disable all tracing before we do anything else */ + tracing_off_permanent(); + WARN_ON_ONCE(1); + return -1; + } + + current->trace_recursion |= 1 << level; + + return 0; +} + +static void trace_recursive_unlock(void) +{ + int level; + + level = trace_irq_level(); + + WARN_ON_ONCE(!current->trace_recursion & (1 << level)); + + current->trace_recursion &= ~(1 << level); +} + static DEFINE_PER_CPU(int, rb_need_resched); /** @@ -1514,6 +1548,9 @@ ring_buffer_lock_reserve(struct ring_buffer *buffer, unsigned long length) /* If we are tracing schedule, we don't want to recurse */ resched = ftrace_preempt_disable(); + if (trace_recursive_lock()) + goto out_nocheck; + cpu = raw_smp_processor_id(); if (!cpumask_test_cpu(cpu, buffer->cpumask)) @@ -1543,6 +1580,9 @@ ring_buffer_lock_reserve(struct ring_buffer *buffer, unsigned long length) return event; out: + trace_recursive_unlock(); + + out_nocheck: ftrace_preempt_enable(resched); return NULL; } @@ -1581,6 +1621,8 @@ int ring_buffer_unlock_commit(struct ring_buffer *buffer, rb_commit(cpu_buffer, event); + trace_recursive_unlock(); + /* * Only the last preempt count needs to restore preemption. */ |