[RFC PATCH v2 02/15] tracing: kprobes: Output kprobe event to printk buffer

Masami Hiramatsu
2019-07-15T05:11:39Z

Since kprobe-events use event_trigger_unlock_commit_regs() directly,
that events doesn't show up in printk buffer if "tp_printk" is set.

Use trace_event_buffer_commit() in kprobe events so that it can
invoke output_printk() as same as other trace events.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
include/linux/trace_events.h | 1 +
kernel/trace/trace.c | 4 +--
kernel/trace/trace_events.c | 1 +
kernel/trace/trace_kprobe.c | 57 +++++++++++++++++++++---------------------
4 files changed, 32 insertions(+), 31 deletions(-)

diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index 5150436783e8..8912ccdb3d4b 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -211,6 +211,7 @@ struct trace_event_buffer {
void *entry;
unsigned long flags;
int pc;
+ struct pt_regs *regs;
};

void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 047f37816bf1..30f09c058f79 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2572,9 +2572,9 @@ void trace_event_buffer_commit(struct trace_event_buffer *fbuffer)
if (static_key_false(&tracepoint_printk_key.key))
output_printk(fbuffer);

- event_trigger_unlock_commit(fbuffer->trace_file, fbuffer->buffer,
+ event_trigger_unlock_commit_regs(fbuffer->trace_file, fbuffer->buffer,
fbuffer->event, fbuffer->entry,
- fbuffer->flags, fbuffer->pc);
+ fbuffer->flags, fbuffer->pc, fbuffer->regs);
}
EXPORT_SYMBOL_GPL(trace_event_buffer_commit);

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index c7506bc81b75..22cf08bd2317 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -271,6 +271,7 @@ void *trace_event_buffer_reserve(struct trace_event_buffer *fbuffer,
if (!fbuffer->event)
return NULL;

+ fbuffer->regs = NULL;
fbuffer->entry = ring_buffer_event_data(fbuffer->event);
return fbuffer->entry;
}
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 9d483ad9bb6c..6c5145525f90 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -988,10 +988,8 @@ __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
struct trace_event_file *trace_file)
{
struct kprobe_trace_entry_head *entry;
- struct ring_buffer_event *event;
- struct ring_buffer *buffer;
- int size, dsize, pc;
- unsigned long irq_flags;
+ struct trace_event_buffer fbuffer;
+ int dsize;
struct trace_event_call *call = trace_probe_event_call(&tk->tp);

WARN_ON(call != trace_file->event_call);
@@ -999,24 +997,26 @@ __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
if (trace_trigger_soft_disabled(trace_file))
return;

- local_save_flags(irq_flags);
- pc = preempt_count();
+ local_save_flags(fbuffer.flags);
+ fbuffer.pc = preempt_count();
+ fbuffer.trace_file = trace_file;

dsize = __get_data_size(&tk->tp, regs);
- size = sizeof(*entry) + tk->tp.size + dsize;

- event = trace_event_buffer_lock_reserve(&buffer, trace_file,
- call->event.type,
- size, irq_flags, pc);
- if (!event)
+ fbuffer.event =
+ trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file,
+ call->event.type,
+ sizeof(*entry) + tk->tp.size + dsize,
+ fbuffer.flags, fbuffer.pc);
+ if (!fbuffer.event)
return;

- entry = ring_buffer_event_data(event);
+ fbuffer.regs = regs;
+ entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
entry->ip = (unsigned long)tk->rp.kp.addr;
store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);

- event_trigger_unlock_commit_regs(trace_file, buffer, event,
- entry, irq_flags, pc, regs);
+ trace_event_buffer_commit(&fbuffer);
}

static void
@@ -1036,10 +1036,8 @@ __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
struct trace_event_file *trace_file)
{
struct kretprobe_trace_entry_head *entry;
- struct ring_buffer_event *event;
- struct ring_buffer *buffer;
- int size, pc, dsize;
- unsigned long irq_flags;
+ struct trace_event_buffer fbuffer;
+ int dsize;
struct trace_event_call *call = trace_probe_event_call(&tk->tp);

WARN_ON(call != trace_file->event_call);
@@ -1047,25 +1045,26 @@ __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
if (trace_trigger_soft_disabled(trace_file))
return;

- local_save_flags(irq_flags);
- pc = preempt_count();
+ local_save_flags(fbuffer.flags);
+ fbuffer.pc = preempt_count();
+ fbuffer.trace_file = trace_file;

dsize = __get_data_size(&tk->tp, regs);
- size = sizeof(*entry) + tk->tp.size + dsize;
-
- event = trace_event_buffer_lock_reserve(&buffer, trace_file,
- call->event.type,
- size, irq_flags, pc);
- if (!event)
+ fbuffer.event =
+ trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file,
+ call->event.type,
+ sizeof(*entry) + tk->tp.size + dsize,
+ fbuffer.flags, fbuffer.pc);
+ if (!fbuffer.event)
return;

- entry = ring_buffer_event_data(event);
+ fbuffer.regs = regs;
+ entry = fbuffer.entry = ring_buffer_event_data(fbuffer.event);
entry->func = (unsigned long)tk->rp.kp.addr;
entry->ret_ip = (unsigned long)ri->ret_addr;
store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);

- event_trigger_unlock_commit_regs(trace_file, buffer, event,
- entry, irq_flags, pc, regs);
+ trace_event_buffer_commit(&fbuffer);
}

static void