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Diffstat (limited to 'kernel/trace/trace.c')
-rw-r--r--kernel/trace/trace.c59
1 files changed, 47 insertions, 12 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 1f835a83cb2c..4f1dade56981 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -704,7 +704,7 @@ __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
void
update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
{
- struct ring_buffer *buf = tr->buffer;
+ struct ring_buffer *buf;
if (trace_stop_count)
return;
@@ -719,6 +719,7 @@ update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
arch_spin_lock(&ftrace_max_lock);
+ buf = tr->buffer;
tr->buffer = max_tr.buffer;
max_tr.buffer = buf;
@@ -2880,11 +2881,25 @@ static int set_tracer_option(struct tracer *trace, char *cmp, int neg)
return -EINVAL;
}
-static void set_tracer_flags(unsigned int mask, int enabled)
+/* Some tracers require overwrite to stay enabled */
+int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set)
+{
+ if (tracer->enabled && (mask & TRACE_ITER_OVERWRITE) && !set)
+ return -1;
+
+ return 0;
+}
+
+int set_tracer_flag(unsigned int mask, int enabled)
{
/* do nothing if flag is already set */
if (!!(trace_flags & mask) == !!enabled)
- return;
+ return 0;
+
+ /* Give the tracer a chance to approve the change */
+ if (current_trace->flag_changed)
+ if (current_trace->flag_changed(current_trace, mask, !!enabled))
+ return -EINVAL;
if (enabled)
trace_flags |= mask;
@@ -2894,18 +2909,24 @@ static void set_tracer_flags(unsigned int mask, int enabled)
if (mask == TRACE_ITER_RECORD_CMD)
trace_event_enable_cmd_record(enabled);
- if (mask == TRACE_ITER_OVERWRITE)
+ if (mask == TRACE_ITER_OVERWRITE) {
ring_buffer_change_overwrite(global_trace.buffer, enabled);
+#ifdef CONFIG_TRACER_MAX_TRACE
+ ring_buffer_change_overwrite(max_tr.buffer, enabled);
+#endif
+ }
if (mask == TRACE_ITER_PRINTK)
trace_printk_start_stop_comm(enabled);
+
+ return 0;
}
static int trace_set_options(char *option)
{
char *cmp;
int neg = 0;
- int ret = 0;
+ int ret = -ENODEV;
int i;
cmp = strstrip(option);
@@ -2915,19 +2936,20 @@ static int trace_set_options(char *option)
cmp += 2;
}
+ mutex_lock(&trace_types_lock);
+
for (i = 0; trace_options[i]; i++) {
if (strcmp(cmp, trace_options[i]) == 0) {
- set_tracer_flags(1 << i, !neg);
+ ret = set_tracer_flag(1 << i, !neg);
break;
}
}
/* If no option could be set, test the specific tracer options */
- if (!trace_options[i]) {
- mutex_lock(&trace_types_lock);
+ if (!trace_options[i])
ret = set_tracer_option(current_trace, cmp, neg);
- mutex_unlock(&trace_types_lock);
- }
+
+ mutex_unlock(&trace_types_lock);
return ret;
}
@@ -2937,6 +2959,7 @@ tracing_trace_options_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
char buf[64];
+ int ret;
if (cnt >= sizeof(buf))
return -EINVAL;
@@ -2946,7 +2969,9 @@ tracing_trace_options_write(struct file *filp, const char __user *ubuf,
buf[cnt] = 0;
- trace_set_options(buf);
+ ret = trace_set_options(buf);
+ if (ret < 0)
+ return ret;
*ppos += cnt;
@@ -3250,6 +3275,9 @@ static int tracing_set_tracer(const char *buf)
goto out;
trace_branch_disable();
+
+ current_trace->enabled = false;
+
if (current_trace->reset)
current_trace->reset(tr);
@@ -3294,6 +3322,7 @@ static int tracing_set_tracer(const char *buf)
}
current_trace = t;
+ current_trace->enabled = true;
trace_branch_enable(tr);
out:
mutex_unlock(&trace_types_lock);
@@ -4780,7 +4809,13 @@ trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
if (val != 0 && val != 1)
return -EINVAL;
- set_tracer_flags(1 << index, val);
+
+ mutex_lock(&trace_types_lock);
+ ret = set_tracer_flag(1 << index, val);
+ mutex_unlock(&trace_types_lock);
+
+ if (ret < 0)
+ return ret;
*ppos += cnt;
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