[RFC PATCH 10/32] function_graph: Have the instances use their own ftrace_ops for filtering

Masami Hiramatsu (Google)
2023-11-05T16:08:39Z

From: Steven Rostedt (VMware) <rostedt@goodmis.org>

Allow for instances to have their own ftrace_ops part of the fgraph_ops that
makes the funtion_graph tracer filter on the set_ftrace_filter file of the
instance and not the top instance.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
include/linux/ftrace.h | 1 +
kernel/trace/fgraph.c | 60 +++++++++++++++++++++-------------
kernel/trace/ftrace.c | 6 ++-
kernel/trace/trace.h | 16 +++++----
kernel/trace/trace_functions.c | 2 +
kernel/trace/trace_functions_graph.c | 8 +++--
6 files changed, 58 insertions(+), 35 deletions(-)

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 7fd044ae3da5..9dab365c6023 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -1044,6 +1044,7 @@ extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace, struct fgraph
struct fgraph_ops {
trace_func_graph_ent_t entryfunc;
trace_func_graph_ret_t retfunc;
+ struct ftrace_ops ops; /* for the hash lists */
void *private;
};

diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index 1e8c17f70b84..0642f3281b64 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -17,14 +17,6 @@
#include "ftrace_internal.h"
#include "trace.h"

-#ifdef CONFIG_DYNAMIC_FTRACE
-#define ASSIGN_OPS_HASH(opsname, val) \
- .func_hash = val, \
- .local_hash.regex_lock = __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
-#else
-#define ASSIGN_OPS_HASH(opsname, val)
-#endif
-
#define FGRAPH_RET_SIZE sizeof(struct ftrace_ret_stack)
#define FGRAPH_RET_INDEX (FGRAPH_RET_SIZE / sizeof(long))

@@ -338,9 +330,6 @@ int function_graph_enter(unsigned long ret, unsigned long func,
return -EBUSY;
#endif

- if (!ftrace_ops_test(&global_ops, func, NULL))
- return -EBUSY;
-
trace.func = func;
trace.depth = ++current->curr_ret_depth;

@@ -361,7 +350,8 @@ int function_graph_enter(unsigned long ret, unsigned long func,
atomic_inc(&current->trace_overrun);
break;
}
- if (fgraph_array[i]->entryfunc(&trace, fgraph_array[i])) {
+ if (ftrace_ops_test(&gops->ops, func, NULL) &&
+ gops->entryfunc(&trace, gops)) {
offset = current->curr_ret_stack;
/* Check the top level stored word */
type = get_fgraph_type(current, offset - 1);
@@ -656,17 +646,25 @@ unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
}
#endif /* HAVE_FUNCTION_GRAPH_RET_ADDR_PTR */

-static struct ftrace_ops graph_ops = {
- .func = ftrace_graph_func,
- .flags = FTRACE_OPS_FL_INITIALIZED |
- FTRACE_OPS_FL_PID |
- FTRACE_OPS_GRAPH_STUB,
+void fgraph_init_ops(struct ftrace_ops *dst_ops,
+ struct ftrace_ops *src_ops)
+{
+ dst_ops->func = ftrace_stub;
+ dst_ops->flags = FTRACE_OPS_FL_PID | FTRACE_OPS_FL_STUB;
+
#ifdef FTRACE_GRAPH_TRAMP_ADDR
- .trampoline = FTRACE_GRAPH_TRAMP_ADDR,
+ dst_ops->trampoline = FTRACE_GRAPH_TRAMP_ADDR;
/* trampoline_size is only needed for dynamically allocated tramps */
#endif
- ASSIGN_OPS_HASH(graph_ops, &global_ops.local_hash)
-};
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+ if (src_ops) {
+ dst_ops->func_hash = &src_ops->local_hash;
+ mutex_init(&dst_ops->local_hash.regex_lock);
+ dst_ops->flags |= FTRACE_OPS_FL_INITIALIZED;
+ }
+#endif
+}

void ftrace_graph_sleep_time_control(bool enable)
{
@@ -871,11 +869,20 @@ static int start_graph_tracing(void)

int register_ftrace_graph(struct fgraph_ops *gops)
{
+ int command = 0;
int ret = 0;
int i;

mutex_lock(&ftrace_lock);

+ if (!gops->ops.func) {
+ gops->ops.flags |= FTRACE_OPS_FL_STUB;
+ gops->ops.func = ftrace_stub;
+#ifdef FTRACE_GRAPH_TRAMP_ADDR
+ gops->ops.trampoline = FTRACE_GRAPH_TRAMP_ADDR;
+#endif
+ }
+
if (!fgraph_array[0]) {
/* The array must always have real data on it */
for (i = 0; i < FGRAPH_ARRAY_SIZE; i++) {
@@ -912,9 +919,10 @@ int register_ftrace_graph(struct fgraph_ops *gops)
*/
ftrace_graph_return = return_run;
ftrace_graph_entry = entry_run;
-
- ret = ftrace_startup(&graph_ops, FTRACE_START_FUNC_RET);
+ command = FTRACE_START_FUNC_RET;
}
+
+ ret = ftrace_startup(&gops->ops, command);
out:
mutex_unlock(&ftrace_lock);
return ret;
@@ -922,6 +930,7 @@ int register_ftrace_graph(struct fgraph_ops *gops)

void unregister_ftrace_graph(struct fgraph_ops *gops)
{
+ int command = 0;
int i;

mutex_lock(&ftrace_lock);
@@ -944,10 +953,15 @@ void unregister_ftrace_graph(struct fgraph_ops *gops)
}

ftrace_graph_active--;
+
+ if (!ftrace_graph_active)
+ command = FTRACE_STOP_FUNC_RET;
+
+ ftrace_shutdown(&gops->ops, command);
+
if (!ftrace_graph_active) {
ftrace_graph_return = ftrace_stub_graph;
ftrace_graph_entry = ftrace_graph_entry_stub;
- ftrace_shutdown(&graph_ops, FTRACE_STOP_FUNC_RET);
unregister_pm_notifier(&ftrace_suspend_notifier);
unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
}
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 83fbfb7b48f8..c4cc2a9d0047 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3050,6 +3050,8 @@ int ftrace_startup(struct ftrace_ops *ops, int command)
if (unlikely(ftrace_disabled))
return -ENODEV;

+ ftrace_ops_init(ops);
+
ret = __register_ftrace_function(ops);
if (ret)
return ret;
@@ -7319,7 +7321,7 @@ __init void ftrace_init_global_array_ops(struct trace_array *tr)
tr->ops = &global_ops;
tr->ops->private = tr;
ftrace_init_trace_array(tr);
- init_array_fgraph_ops(tr);
+ init_array_fgraph_ops(tr, tr->ops);
}

void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
@@ -8051,7 +8053,7 @@ static int register_ftrace_function_nolock(struct ftrace_ops *ops)
*/
int register_ftrace_function(struct ftrace_ops *ops)
{
- int ret;
+ int ret = -1;

lock_direct_mutex();
ret = prepare_direct_functions_for_ipmodify(ops);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 73fe789ba143..531cfdb44911 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -886,8 +886,8 @@ extern int __trace_graph_entry(struct trace_array *tr,
extern void __trace_graph_return(struct trace_array *tr,
struct ftrace_graph_ret *trace,
unsigned int trace_ctx);
-extern void init_array_fgraph_ops(struct trace_array *tr);
-extern int allocate_fgraph_ops(struct trace_array *tr);
+extern void init_array_fgraph_ops(struct trace_array *tr, struct ftrace_ops *ops);
+extern int allocate_fgraph_ops(struct trace_array *tr, struct ftrace_ops *ops);
extern void free_fgraph_ops(struct trace_array *tr);

#ifdef CONFIG_DYNAMIC_FTRACE
@@ -970,6 +970,7 @@ static inline int ftrace_graph_notrace_addr(unsigned long addr)
preempt_enable_notrace();
return ret;
}
+
#else
static inline int ftrace_graph_addr(struct ftrace_graph_ent *trace)
{
@@ -995,18 +996,19 @@ static inline bool ftrace_graph_ignore_func(struct ftrace_graph_ent *trace)
(fgraph_max_depth && trace->depth >= fgraph_max_depth);
}

+void fgraph_init_ops(struct ftrace_ops *dst_ops,
+ struct ftrace_ops *src_ops);
+
#else /* CONFIG_FUNCTION_GRAPH_TRACER */
static inline enum print_line_t
print_graph_function_flags(struct trace_iterator *iter, u32 flags)
{
return TRACE_TYPE_UNHANDLED;
}
-static inline void init_array_fgraph_ops(struct trace_array *tr) { }
-static inline int allocate_fgraph_ops(struct trace_array *tr)
-{
- return 0;
-}
static inline void free_fgraph_ops(struct trace_array *tr) { }
+/* ftrace_ops may not be defined */
+#define init_array_fgraph_ops(tr, ops) do { } while (0)
+#define allocate_fgraph_ops(tr, ops) ({ 0; })
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */

extern struct list_head ftrace_pids;
diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index 8e8da0d0ee52..13bf2415245d 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -91,7 +91,7 @@ int ftrace_create_function_files(struct trace_array *tr,
if (!tr->ops)
return -EINVAL;

- ret = allocate_fgraph_ops(tr);
+ ret = allocate_fgraph_ops(tr, tr->ops);
if (ret) {
kfree(tr->ops);
return ret;
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 9ccc904a7703..7f30652f0e97 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -288,7 +288,7 @@ static struct fgraph_ops funcgraph_ops = {
.retfunc = &trace_graph_return,
};

-int allocate_fgraph_ops(struct trace_array *tr)
+int allocate_fgraph_ops(struct trace_array *tr, struct ftrace_ops *ops)
{
struct fgraph_ops *gops;

@@ -301,6 +301,9 @@ int allocate_fgraph_ops(struct trace_array *tr)

tr->gops = gops;
gops->private = tr;
+
+ fgraph_init_ops(&gops->ops, ops);
+
return 0;
}

@@ -309,10 +312,11 @@ void free_fgraph_ops(struct trace_array *tr)
kfree(tr->gops);
}

-__init void init_array_fgraph_ops(struct trace_array *tr)
+__init void init_array_fgraph_ops(struct trace_array *tr, struct ftrace_ops *ops)
{
tr->gops = &funcgraph_ops;
funcgraph_ops.private = tr;
+ fgraph_init_ops(&tr->gops->ops, ops);
}

static int graph_trace_init(struct trace_array *tr)