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Subject[PATCH -tip -v12 10/11] tracing: Generate names for each kprobe event automatically
Date
Generate names for each kprobe event based on the probe point,
and remove generic k*probe event types because there is no user
of those types.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
---

Documentation/trace/kprobetrace.txt | 3 +-
kernel/trace/trace_event_types.h | 18 ----------
kernel/trace/trace_kprobe.c | 64 ++++++++++++++++++-----------------
3 files changed, 35 insertions(+), 50 deletions(-)

diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt
index b29a54b..437ad49 100644
--- a/Documentation/trace/kprobetrace.txt
+++ b/Documentation/trace/kprobetrace.txt
@@ -28,7 +28,8 @@ Synopsis of kprobe_events
p[:EVENT] SYMBOL[+offs|-offs]|MEMADDR [FETCHARGS] : Set a probe
r[:EVENT] SYMBOL[+0] [FETCHARGS] : Set a return probe

- EVENT : Event name.
+ EVENT : Event name. If omitted, the event name is generated
+ based on SYMBOL+offs or MEMADDR.
SYMBOL[+offs|-offs] : Symbol+offset where the probe is inserted.
MEMADDR : Address where the probe is inserted.

diff --git a/kernel/trace/trace_event_types.h b/kernel/trace/trace_event_types.h
index 186b598..e74f090 100644
--- a/kernel/trace/trace_event_types.h
+++ b/kernel/trace/trace_event_types.h
@@ -175,22 +175,4 @@ TRACE_EVENT_FORMAT(kmem_free, TRACE_KMEM_FREE, kmemtrace_free_entry, ignore,
TP_RAW_FMT("type:%u call_site:%lx ptr:%p")
);

-TRACE_EVENT_FORMAT(kprobe, TRACE_KPROBE, kprobe_trace_entry, ignore,
- TRACE_STRUCT(
- TRACE_FIELD(unsigned long, ip, ip)
- TRACE_FIELD(int, nargs, nargs)
- TRACE_FIELD_ZERO(unsigned long, args)
- ),
- TP_RAW_FMT("%08lx: args:0x%lx ...")
-);
-
-TRACE_EVENT_FORMAT(kretprobe, TRACE_KRETPROBE, kretprobe_trace_entry, ignore,
- TRACE_STRUCT(
- TRACE_FIELD(unsigned long, func, func)
- TRACE_FIELD(unsigned long, ret_ip, ret_ip)
- TRACE_FIELD(int, nargs, nargs)
- TRACE_FIELD_ZERO(unsigned long, args)
- ),
- TP_RAW_FMT("%08lx <- %08lx: args:0x%lx ...")
-);
#undef TRACE_SYSTEM
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 67c33e1..3444d1d 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -34,6 +34,7 @@

#define MAX_TRACE_ARGS 128
#define MAX_ARGSTR_LEN 63
+#define MAX_EVENT_NAME_LEN 64

/* currently, trace_kprobe only supports X86. */

@@ -272,11 +273,11 @@ static struct trace_probe *alloc_trace_probe(const char *symbol,
if (!tp->symbol)
goto error;
}
- if (event) {
- tp->call.name = kstrdup(event, GFP_KERNEL);
- if (!tp->call.name)
- goto error;
- }
+ if (!event)
+ goto error;
+ tp->call.name = kstrdup(event, GFP_KERNEL);
+ if (!tp->call.name)
+ goto error;

INIT_LIST_HEAD(&tp->list);
return tp;
@@ -306,7 +307,7 @@ static struct trace_probe *find_probe_event(const char *event)
struct trace_probe *tp;

list_for_each_entry(tp, &probe_list, list)
- if (tp->call.name && !strcmp(tp->call.name, event))
+ if (!strcmp(tp->call.name, event))
return tp;
return NULL;
}
@@ -322,8 +323,7 @@ static void __unregister_trace_probe(struct trace_probe *tp)
/* Unregister a trace_probe and probe_event: call with locking probe_lock */
static void unregister_trace_probe(struct trace_probe *tp)
{
- if (tp->call.name)
- unregister_probe_event(tp);
+ unregister_probe_event(tp);
__unregister_trace_probe(tp);
list_del(&tp->list);
}
@@ -352,18 +352,16 @@ static int register_trace_probe(struct trace_probe *tp)
goto end;
}
/* register as an event */
- if (tp->call.name) {
- old_tp = find_probe_event(tp->call.name);
- if (old_tp) {
- /* delete old event */
- unregister_trace_probe(old_tp);
- free_trace_probe(old_tp);
- }
- ret = register_probe_event(tp);
- if (ret) {
- pr_warning("Faild to register probe event(%d)\n", ret);
- __unregister_trace_probe(tp);
- }
+ old_tp = find_probe_event(tp->call.name);
+ if (old_tp) {
+ /* delete old event */
+ unregister_trace_probe(old_tp);
+ free_trace_probe(old_tp);
+ }
+ ret = register_probe_event(tp);
+ if (ret) {
+ pr_warning("Faild to register probe event(%d)\n", ret);
+ __unregister_trace_probe(tp);
}
list_add_tail(&tp->list, &probe_list);
end:
@@ -566,7 +564,18 @@ static int create_trace_probe(int argc, char **argv)
argc -= 2; argv += 2;

/* setup a probe */
- tp = alloc_trace_probe(symbol, event, argc);
+ if (!event) {
+ /* Make a new event name */
+ char buf[MAX_EVENT_NAME_LEN];
+ if (symbol)
+ snprintf(buf, MAX_EVENT_NAME_LEN, "%c@%s%+ld",
+ is_return ? 'r' : 'p', symbol, offset);
+ else
+ snprintf(buf, MAX_EVENT_NAME_LEN, "%c@0x%p",
+ is_return ? 'r' : 'p', addr);
+ tp = alloc_trace_probe(symbol, buf, argc);
+ } else
+ tp = alloc_trace_probe(symbol, event, argc);
if (IS_ERR(tp))
return PTR_ERR(tp);

@@ -647,8 +656,7 @@ static int probes_seq_show(struct seq_file *m, void *v)
char buf[MAX_ARGSTR_LEN + 1];

seq_printf(m, "%c", probe_is_return(tp) ? 'r' : 'p');
- if (tp->call.name)
- seq_printf(m, ":%s", tp->call.name);
+ seq_printf(m, ":%s", tp->call.name);

if (tp->symbol)
seq_printf(m, " %s%+ld", probe_symbol(tp), probe_offset(tp));
@@ -766,10 +774,7 @@ static __kprobes int kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
struct ring_buffer_event *event;
int size, i, pc;
unsigned long irq_flags;
- struct ftrace_event_call *call = &event_kprobe;
-
- if (&tp->call.name)
- call = &tp->call;
+ struct ftrace_event_call *call = &tp->call;

local_save_flags(irq_flags);
pc = preempt_count();
@@ -801,10 +806,7 @@ static __kprobes int kretprobe_trace_func(struct kretprobe_instance *ri,
struct ring_buffer_event *event;
int size, i, pc;
unsigned long irq_flags;
- struct ftrace_event_call *call = &event_kretprobe;
-
- if (&tp->call.name)
- call = &tp->call;
+ struct ftrace_event_call *call = &tp->call;

local_save_flags(irq_flags);
pc = preempt_count();

--
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division

e-mail: mhiramat@redhat.com


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