[PATCH] tracing/trace: apply filters on all output channels

From: Pingfan Liu
Date: Sat Aug 14 2021 - 00:11:10 EST


The event filters are not applied on all of the output, which results in
the flood of printk when using tp_printk. Unfolding
event_trigger_unlock_commit_regs() into trace_event_buffer_commit(), so
the filters can be applied on every output.

Signed-off-by: Pingfan Liu <kernelfans@xxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
To: linux-kernel@xxxxxxxxxxxxxxx
---
kernel/trace/trace.c | 18 +++++++++++++++---
kernel/trace/trace.h | 32 --------------------------------
2 files changed, 15 insertions(+), 35 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 33899a71fdc1..a1adb29ef5c1 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2897,14 +2897,26 @@ int tracepoint_printk_sysctl(struct ctl_table *table, int write,

void trace_event_buffer_commit(struct trace_event_buffer *fbuffer)
{
+ enum event_trigger_type tt = ETT_NONE;
+ struct trace_event_file *file = fbuffer->trace_file;
+
+ if (__event_trigger_test_discard(file, fbuffer->buffer, fbuffer->event,
+ fbuffer->entry, &tt))
+ goto discard;
+
if (static_key_false(&tracepoint_printk_key.key))
output_printk(fbuffer);

if (static_branch_unlikely(&trace_event_exports_enabled))
ftrace_exports(fbuffer->event, TRACE_EXPORT_EVENT);
- event_trigger_unlock_commit_regs(fbuffer->trace_file, fbuffer->buffer,
- fbuffer->event, fbuffer->entry,
- fbuffer->trace_ctx, fbuffer->regs);
+
+ trace_buffer_unlock_commit_regs(file->tr, fbuffer->buffer,
+ fbuffer->event, fbuffer->trace_ctx, fbuffer->regs);
+
+discard:
+ if (tt)
+ event_triggers_post_call(file, tt);
+
}
EXPORT_SYMBOL_GPL(trace_event_buffer_commit);

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index a180abf76d4e..4a0e693000c6 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1389,38 +1389,6 @@ event_trigger_unlock_commit(struct trace_event_file *file,
event_triggers_post_call(file, tt);
}

-/**
- * event_trigger_unlock_commit_regs - handle triggers and finish event commit
- * @file: The file pointer associated with the event
- * @buffer: The ring buffer that the event is being written to
- * @event: The event meta data in the ring buffer
- * @entry: The event itself
- * @trace_ctx: The tracing context flags.
- *
- * This is a helper function to handle triggers that require data
- * from the event itself. It also tests the event against filters and
- * if the event is soft disabled and should be discarded.
- *
- * Same as event_trigger_unlock_commit() but calls
- * trace_buffer_unlock_commit_regs() instead of trace_buffer_unlock_commit().
- */
-static inline void
-event_trigger_unlock_commit_regs(struct trace_event_file *file,
- struct trace_buffer *buffer,
- struct ring_buffer_event *event,
- void *entry, unsigned int trace_ctx,
- struct pt_regs *regs)
-{
- enum event_trigger_type tt = ETT_NONE;
-
- if (!__event_trigger_test_discard(file, buffer, event, entry, &tt))
- trace_buffer_unlock_commit_regs(file->tr, buffer, event,
- trace_ctx, regs);
-
- if (tt)
- event_triggers_post_call(file, tt);
-}
-
#define FILTER_PRED_INVALID ((unsigned short)-1)
#define FILTER_PRED_IS_RIGHT (1 << 15)
#define FILTER_PRED_FOLD (1 << 15)
--
2.29.2