diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index a71158369fd46524cc0551bf3ff3dcc5f16c6b99..e90e81ef6ab9ef7889fb35ac2d14a440db149faf 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -21,6 +21,7 @@ struct task_struct;
struct exec_domain;
#include <asm/processor.h>
#include <asm/ftrace.h>
+#include <asm/atomic.h>
struct thread_info {
struct task_struct *task; /* main task structure */
@@ -45,6 +46,11 @@ struct thread_info {
int curr_ret_stack;
/* Stack of return addresses for return function tracing */
struct ftrace_ret_stack ret_stack[FTRACE_RET_STACK_SIZE];
+ /*
+ * Number of functions that haven't been traced
+ * because of depth overrun.
+ */
+ atomic_t trace_overrun;
#endif
};
@@ -61,6 +67,7 @@ struct thread_info {
.fn = do_no_restart_syscall, \
}, \
.curr_ret_stack = -1,\
+ .trace_overrun = ATOMIC_INIT(0) \
}
#else
#define INIT_THREAD_INFO(tsk) \
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 924153edd97331c1b244ec63446f0978e43f5fb1..356bb1eb6e9a5271d91224a872856a868fc59780 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -353,8 +353,10 @@ static int push_return_trace(unsigned long ret, unsigned long long time,
struct thread_info *ti = current_thread_info();
/* The return trace stack is full */
- if (ti->curr_ret_stack == FTRACE_RET_STACK_SIZE - 1)
+ if (ti->curr_ret_stack == FTRACE_RET_STACK_SIZE - 1) {
+ atomic_inc(&ti->trace_overrun);
return -EBUSY;
+ }
index = ++ti->curr_ret_stack;
barrier();
@@ -367,7 +369,7 @@ static int push_return_trace(unsigned long ret, unsigned long long time,
/* Retrieve a function return address to the trace stack on thread info.*/
static void pop_return_trace(unsigned long *ret, unsigned long long *time,
- unsigned long *func)
+ unsigned long *func, unsigned long *overrun)
{
int index;
@@ -376,6 +378,7 @@ static void pop_return_trace(unsigned long *ret, unsigned long long *time,
*ret = ti->ret_stack[index].ret;
*func = ti->ret_stack[index].func;
*time = ti->ret_stack[index].calltime;
+ *overrun = atomic_read(&ti->trace_overrun);
ti->curr_ret_stack--;
}
@@ -386,7 +389,8 @@ static void pop_return_trace(unsigned long *ret, unsigned long long *time,
unsigned long ftrace_return_to_handler(void)
{
struct ftrace_retfunc trace;
- pop_return_trace(&trace.ret, &trace.calltime, &trace.func);
+ pop_return_trace(&trace.ret, &trace.calltime, &trace.func,
+ &trace.overrun);
trace.rettime = cpu_clock(raw_smp_processor_id());
ftrace_function_return(&trace);
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index f1af1aab00e6ffaa3e463ffe3522df63918953d8..f7ba4ea5e128dca40746569fb580965cd12f9faf 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -318,6 +318,8 @@ struct ftrace_retfunc {
unsigned long func; /* Current function */
unsigned long long calltime;
unsigned long long rettime;
+ /* Number of functions that overran the depth limit for current task */
+ unsigned long overrun;
};
#ifdef CONFIG_FUNCTION_RET_TRACER
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 61c8cc36028ae37d5c5c1c9bc9ac2292d3493f57..c8e0db46420674184abd181666034fa6da1cbefc 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2016,6 +2016,7 @@ static inline void setup_thread_stack(struct task_struct *p, struct task_struct
* used.
*/
task_thread_info(p)->curr_ret_stack = -1;
+ atomic_set(&task_thread_info(p)->trace_overrun, 0);
#endif
}
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 9531fddcfb8dba67dc01755dc7f3b3082077ffdf..e97c29a6e7b09cb6850dfb8cb1caaab9c24f65bc 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -853,6 +853,7 @@ static void __trace_function_return(struct trace_array *tr,
entry->parent_ip = trace->ret;
entry->rettime = trace->rettime;
entry->calltime = trace->calltime;
+ entry->overrun = trace->overrun;
ring_buffer_unlock_commit(global_trace.buffer, event, irq_flags);
}
#endif
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 9d22618bf99f4ab72ef95a2bf154b4cc614d2288..2cb12fd98f6b395dbdc1083d01a96b527633f858 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -60,6 +60,7 @@ struct ftrace_ret_entry {
unsigned long parent_ip;
unsigned long long calltime;
unsigned long long rettime;
+ unsigned long overrun;
};
extern struct tracer boot_tracer;
diff --git a/kernel/trace/trace_functions_return.c b/kernel/trace/trace_functions_return.c
index a68564af022bff3dafc11d189a8eccfce4c026bd..e00d64509c9c42bc2ef92fca9aa7fcbc9187c702 100644
--- a/kernel/trace/trace_functions_return.c
+++ b/kernel/trace/trace_functions_return.c
@@ -14,6 +14,19 @@
#include "trace.h"
+#define TRACE_RETURN_PRINT_OVERRUN 0x1
+static struct tracer_opt trace_opts[] = {
+ /* Display overruns or not */
+ { TRACER_OPT(overrun, TRACE_RETURN_PRINT_OVERRUN) },
+ { } /* Empty entry */
+};
+
+static struct tracer_flags tracer_flags = {
+ .val = 0, /* Don't display overruns by default */
+ .opts = trace_opts
+};
+
+
static int return_trace_init(struct trace_array *tr)
{
int cpu;
@@ -42,26 +55,39 @@ print_return_function(struct trace_iterator *iter)
ret = trace_seq_printf(s, "%pF -> ", (void *)field->parent_ip);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
+
ret = seq_print_ip_sym(s, field->ip,
trace_flags & TRACE_ITER_SYM_MASK);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
- ret = trace_seq_printf(s, " (%llu ns)\n",
+
+ ret = trace_seq_printf(s, " (%llu ns)",
field->rettime - field->calltime);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
- else
- return TRACE_TYPE_HANDLED;
+
+ if (tracer_flags.val & TRACE_RETURN_PRINT_OVERRUN) {
+ ret = trace_seq_printf(s, " (Overruns: %lu)",
+ field->overrun);
+ if (!ret)
+ return TRACE_TYPE_PARTIAL_LINE;
+ }
+
+ ret = trace_seq_printf(s, "\n");
+ if (!ret)
+ return TRACE_TYPE_PARTIAL_LINE;
+
+ return TRACE_TYPE_HANDLED;
}
return TRACE_TYPE_UNHANDLED;
}
-static struct tracer return_trace __read_mostly =
-{
+static struct tracer return_trace __read_mostly = {
.name = "return",
.init = return_trace_init,
.reset = return_trace_reset,
- .print_line = print_return_function
+ .print_line = print_return_function,
+ .flags = &tracer_flags,
};
static __init int init_return_trace(void)