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-rw-r--r--kernel/trace/trace.c31
-rw-r--r--kernel/trace/trace.h7
-rw-r--r--kernel/trace/trace_irqsoff.c19
-rw-r--r--kernel/trace/trace_sched_wakeup.c18
4 files changed, 61 insertions, 14 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 0c6ce4438d36..17edb1457d1c 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2636,11 +2636,25 @@ 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;
@@ -2656,6 +2670,8 @@ static void set_tracer_flags(unsigned int mask, int enabled)
ring_buffer_change_overwrite(max_tr.buffer, enabled);
#endif
}
+
+ return 0;
}
static ssize_t
@@ -2686,7 +2702,7 @@ tracing_trace_options_write(struct file *filp, const char __user *ubuf,
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;
}
}
@@ -3022,6 +3038,9 @@ static int tracing_set_tracer(const char *buf)
goto out;
trace_branch_disable();
+
+ current_trace->enabled = false;
+
if (current_trace && current_trace->reset)
current_trace->reset(tr);
if (current_trace && current_trace->use_max_tr) {
@@ -3051,6 +3070,7 @@ static int tracing_set_tracer(const char *buf)
goto out;
}
+ current_trace->enabled = true;
trace_branch_enable(tr);
out:
mutex_unlock(&trace_types_lock);
@@ -4387,9 +4407,12 @@ trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
return -EINVAL;
mutex_lock(&trace_types_lock);
- set_tracer_flags(1 << index, val);
+ ret = set_tracer_flag(1 << index, val);
mutex_unlock(&trace_types_lock);
+ if (ret < 0)
+ return ret;
+
*ppos += cnt;
return cnt;
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 092e1f8d18dc..c3c3f6b398d3 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -271,10 +271,14 @@ struct tracer {
enum print_line_t (*print_line)(struct trace_iterator *iter);
/* If you handled the flag setting, return 0 */
int (*set_flag)(u32 old_flags, u32 bit, int set);
+ /* Return 0 if OK with change, else return non-zero */
+ int (*flag_changed)(struct tracer *tracer,
+ u32 mask, int set);
struct tracer *next;
struct tracer_flags *flags;
int print_max;
int use_max_tr;
+ bool enabled;
};
@@ -815,6 +819,9 @@ extern struct list_head ftrace_events;
extern const char *__start___trace_bprintk_fmt[];
extern const char *__stop___trace_bprintk_fmt[];
+int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set);
+int set_tracer_flag(unsigned int mask, int enabled);
+
#undef FTRACE_ENTRY
#define FTRACE_ENTRY(call, struct_name, id, tstruct, print) \
extern struct ftrace_event_call \
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index 20dad0d7a163..1626e1aee71a 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -32,7 +32,7 @@ enum {
static int trace_type __read_mostly;
-static int save_lat_flag;
+static int save_flags;
static void stop_irqsoff_tracer(struct trace_array *tr, int graph);
static int start_irqsoff_tracer(struct trace_array *tr, int graph);
@@ -546,8 +546,11 @@ static void stop_irqsoff_tracer(struct trace_array *tr, int graph)
static void __irqsoff_tracer_init(struct trace_array *tr)
{
- save_lat_flag = trace_flags & TRACE_ITER_LATENCY_FMT;
- trace_flags |= TRACE_ITER_LATENCY_FMT;
+ save_flags = trace_flags;
+
+ /* non overwrite screws up the latency tracers */
+ set_tracer_flag(TRACE_ITER_OVERWRITE, 1);
+ set_tracer_flag(TRACE_ITER_LATENCY_FMT, 1);
tracing_max_latency = 0;
irqsoff_trace = tr;
@@ -561,10 +564,13 @@ static void __irqsoff_tracer_init(struct trace_array *tr)
static void irqsoff_tracer_reset(struct trace_array *tr)
{
+ int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
+ int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
+
stop_irqsoff_tracer(tr, is_graph());
- if (!save_lat_flag)
- trace_flags &= ~TRACE_ITER_LATENCY_FMT;
+ set_tracer_flag(TRACE_ITER_LATENCY_FMT, lat_flag);
+ set_tracer_flag(TRACE_ITER_OVERWRITE, overwrite_flag);
}
static void irqsoff_tracer_start(struct trace_array *tr)
@@ -597,6 +603,7 @@ static struct tracer irqsoff_tracer __read_mostly =
.print_line = irqsoff_print_line,
.flags = &tracer_flags,
.set_flag = irqsoff_set_flag,
+ .flag_changed = trace_keep_overwrite,
#ifdef CONFIG_FTRACE_SELFTEST
.selftest = trace_selftest_startup_irqsoff,
#endif
@@ -630,6 +637,7 @@ static struct tracer preemptoff_tracer __read_mostly =
.print_line = irqsoff_print_line,
.flags = &tracer_flags,
.set_flag = irqsoff_set_flag,
+ .flag_changed = trace_keep_overwrite,
#ifdef CONFIG_FTRACE_SELFTEST
.selftest = trace_selftest_startup_preemptoff,
#endif
@@ -665,6 +673,7 @@ static struct tracer preemptirqsoff_tracer __read_mostly =
.print_line = irqsoff_print_line,
.flags = &tracer_flags,
.set_flag = irqsoff_set_flag,
+ .flag_changed = trace_keep_overwrite,
#ifdef CONFIG_FTRACE_SELFTEST
.selftest = trace_selftest_startup_preemptirqsoff,
#endif
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index e4a70c0c71b6..6857e0c99656 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -36,7 +36,7 @@ static void __wakeup_reset(struct trace_array *tr);
static int wakeup_graph_entry(struct ftrace_graph_ent *trace);
static void wakeup_graph_return(struct ftrace_graph_ret *trace);
-static int save_lat_flag;
+static int save_flags;
#define TRACE_DISPLAY_GRAPH 1
@@ -528,8 +528,11 @@ static void stop_wakeup_tracer(struct trace_array *tr)
static int __wakeup_tracer_init(struct trace_array *tr)
{
- save_lat_flag = trace_flags & TRACE_ITER_LATENCY_FMT;
- trace_flags |= TRACE_ITER_LATENCY_FMT;
+ save_flags = trace_flags;
+
+ /* non overwrite screws up the latency tracers */
+ set_tracer_flag(TRACE_ITER_OVERWRITE, 1);
+ set_tracer_flag(TRACE_ITER_LATENCY_FMT, 1);
tracing_max_latency = 0;
wakeup_trace = tr;
@@ -551,12 +554,15 @@ static int wakeup_rt_tracer_init(struct trace_array *tr)
static void wakeup_tracer_reset(struct trace_array *tr)
{
+ int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT;
+ int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE;
+
stop_wakeup_tracer(tr);
/* make sure we put back any tasks we are tracing */
wakeup_reset(tr);
- if (!save_lat_flag)
- trace_flags &= ~TRACE_ITER_LATENCY_FMT;
+ set_tracer_flag(TRACE_ITER_LATENCY_FMT, lat_flag);
+ set_tracer_flag(TRACE_ITER_OVERWRITE, overwrite_flag);
}
static void wakeup_tracer_start(struct trace_array *tr)
@@ -582,6 +588,7 @@ static struct tracer wakeup_tracer __read_mostly =
.print_line = wakeup_print_line,
.flags = &tracer_flags,
.set_flag = wakeup_set_flag,
+ .flag_changed = trace_keep_overwrite,
#ifdef CONFIG_FTRACE_SELFTEST
.selftest = trace_selftest_startup_wakeup,
#endif
@@ -603,6 +610,7 @@ static struct tracer wakeup_rt_tracer __read_mostly =
.print_line = wakeup_print_line,
.flags = &tracer_flags,
.set_flag = wakeup_set_flag,
+ .flag_changed = trace_keep_overwrite,
#ifdef CONFIG_FTRACE_SELFTEST
.selftest = trace_selftest_startup_wakeup,
#endif
generated by cgit v1.2.3 (git 2.0.4) at 2024-11-19 01:22:04 +0000