From: Kohei Enju <enjuk@xxxxxxxxxx>
Commit c132be2c4fcc ("function_graph: Have the instances use their own
ftrace_ops for filtering"), function profiler (enabled via
function_profile_enabled) has been showing statistics for all functions,
ignoring set_ftrace_filter settings.
While tracers are instantiated, the function profiler is not. Therefore, it
should use the global set_ftrace_filter for consistency. This patch
modifies the function profiler to use the global filter, fixing the
filtering functionality.
Before (filtering not working):
```
root@localhost:~# echo 'vfs*' > /sys/kernel/tracing/set_ftrace_filter
root@localhost:~# echo 1 > /sys/kernel/tracing/function_profile_enabled
root@localhost:~# sleep 1
root@localhost:~# echo 0 > /sys/kernel/tracing/function_profile_enabled
root@localhost:~# head /sys/kernel/tracing/trace_stat/*
Function Hit Time Avg
s^2
-------- --- ---- ---
---
schedule 314 22290594 us 70989.15 us
40372231 us
x64_sys_call 1527 8762510 us 5738.382 us
3414354 us
schedule_hrtimeout_range 176 8665356 us 49234.98 us
405618876 us
__x64_sys_ppoll 324 5656635 us 17458.75 us
19203976 us
do_sys_poll 324 5653747 us 17449.83 us
19214945 us
schedule_timeout 67 5531396 us 82558.15 us
2136740827 us
__x64_sys_pselect6 12 3029540 us 252461.7 us
63296940171 us
do_pselect.constprop.0 12 3029532 us 252461.0 us
63296952931 us
```
After (filtering working):
```
root@localhost:~# echo 'vfs*' > /sys/kernel/tracing/set_ftrace_filter
root@localhost:~# echo 1 > /sys/kernel/tracing/function_profile_enabled
root@localhost:~# sleep 1
root@localhost:~# echo 0 > /sys/kernel/tracing/function_profile_enabled
root@localhost:~# head /sys/kernel/tracing/trace_stat/*
Function Hit Time Avg
s^2
-------- --- ---- ---
---
vfs_write 462 68476.43 us 148.217 us
25874.48 us
vfs_read 641 9611.356 us 14.994 us
28868.07 us
vfs_fstat 890 878.094 us 0.986 us
1.667 us
vfs_fstatat 227 757.176 us 3.335 us
18.928 us
vfs_statx 226 610.610 us 2.701 us
17.749 us
vfs_getattr_nosec 1187 460.919 us 0.388 us
0.326 us
vfs_statx_path 297 343.287 us 1.155 us
11.116 us
vfs_rename 6 291.575 us 48.595 us
9889.236 us
```
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/20250101190820.72534-1-enjuk@xxxxxxxxxx
Fixes: c132be2c4fcc ("function_graph: Have the instances use their own ftrace_ops for filtering")
Signed-off-by: Kohei Enju <enjuk@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
---
kernel/trace/ftrace.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 9b17efb1a87d..2e113f8b13a2 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -902,16 +902,13 @@ static void profile_graph_return(struct ftrace_graph_ret *trace,
}
static struct fgraph_ops fprofiler_ops = {
- .ops = {
- .flags = FTRACE_OPS_FL_INITIALIZED,
- INIT_OPS_HASH(fprofiler_ops.ops)
- },
.entryfunc = &profile_graph_entry,
.retfunc = &profile_graph_return,
};
static int register_ftrace_profiler(void)
{
+ ftrace_ops_set_global_filter(&fprofiler_ops.ops);
return register_ftrace_graph(&fprofiler_ops);
}
@@ -922,12 +919,11 @@ static void unregister_ftrace_profiler(void)
#else
static struct ftrace_ops ftrace_profile_ops __read_mostly = {
.func = function_profile_call,
- .flags = FTRACE_OPS_FL_INITIALIZED,
- INIT_OPS_HASH(ftrace_profile_ops)
};
static int register_ftrace_profiler(void)
{
+ ftrace_ops_set_global_filter(&ftrace_profile_ops);
return register_ftrace_function(&ftrace_profile_ops);
}
--
2.45.2
