[PATCH -tip 0/5] Perf and tracing/kprobe fixes

[PATCH -tip 0/5] Perf and tracing/kprobe fixes

[Masami Hiramatsu]

Hi,

This series of patches fixes a memory leak and perf probe bugs.
It also adds a check of invalid argument name for special characters
which will cause a fail on perf-trace event format parsing, and
assigns "argN" name for no-name arguments.

Thank you,

---

Masami Hiramatsu (5):
      tracing/kprobe: Check invalid argument name
      tracing/kprobes: Set a name for each argument automatically
      perf probe: Don't make argument names from raw parameters
      perf probe: Fix return probe support
      tracing/kprobe: Fix a memory leak in error case


 kernel/trace/trace_kprobe.c    |   43 +++++++++++++++++++++++-----------------
 tools/perf/util/probe-event.c  |    1 +
 tools/perf/util/probe-finder.c |   42 +++++++++++++++++++++++++++------------
 3 files changed, 55 insertions(+), 31 deletions(-)

-- 
Masami HIRAMATSU
2nd Dept. Linux Technology Center
Hitachi, Ltd., Systems Development Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com

[PATCH -tip 1/5] tracing/kprobe: Fix a memory leak in error case

[Masami Hiramatsu]

Fix a memory leak which happens when a field name conflicts
with others. In error case, free_trace_probe() will free all
arguments until nr_args, so this increments nr_args the
begining of the loop instead of the end.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: linux-kernel@vger.kernel.org
---

 kernel/trace/trace_kprobe.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 8b27c98..0116c03 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -992,6 +992,9 @@ static int create_trace_probe(int argc, char **argv)
 	/* parse arguments */
 	ret = 0;
 	for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
+		/* Increment count for freeing args in error case */
+		tp->nr_args++;
+
 		/* Parse argument name */
 		arg = strchr(argv[i], '=');
 		if (arg)
@@ -1021,11 +1024,8 @@ static int create_trace_probe(int argc, char **argv)
 		ret = parse_probe_arg(arg, tp, &tp->args[i], is_return);
 		if (ret) {
 			pr_info("Parse error at argument%d. (%d)\n", i, ret);
-			kfree(tp->args[i].name);
 			goto error;
 		}
-
-		tp->nr_args++;
 	}
 
 	ret = register_trace_probe(tp);

[PATCH -tip 2/5] perf probe: Fix return probe support

[Masami Hiramatsu]

Fix a bug to support %return probe syntax again. Previous commit
4235b04 has a bug which disables the %return syntax on perf probe.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: linux-kernel@vger.kernel.org
---

 tools/perf/util/probe-event.c  |    1 +
 tools/perf/util/probe-finder.c |   10 ++++++++++
 2 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index e72f05c..fcc16e4 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -1539,6 +1539,7 @@ static int convert_to_probe_trace_events(struct perf_probe_event *pev,
 		goto error;
 	}
 	tev->point.offset = pev->point.offset;
+	tev->point.retprobe = pev->point.retprobe;
 	tev->nargs = pev->nargs;
 	if (tev->nargs) {
 		tev->args = zalloc(sizeof(struct probe_trace_arg)
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 5251366..9b0e1b1 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -783,6 +783,16 @@ static int convert_probe_point(Dwarf_Die *sp_die, struct probe_finder *pf)
 		/* This function has no name. */
 		tev->point.offset = (unsigned long)pf->addr;
 
+	/* Return probe must be on the head of a subprogram */
+	if (pf->pev->point.retprobe) {
+		if (tev->point.offset != 0) {
+			pr_warning("Return probe must be on the head of"
+				   " a real function\n");
+			return -EINVAL;
+		}
+		tev->point.retprobe = true;
+	}
+
 	pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
 		 tev->point.offset);
 

[PATCH -tip 3/5] perf probe: Don't make argument names from raw parameters

[Masami Hiramatsu]

Don't make argument names from raw parameters (means
the parameters are written in kprobe-tracer syntax),
because the argument syntax may include special characters.
Just leave it, then kprobe-tracer gives a new name.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reported-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: linux-kernel@vger.kernel.org
---

 tools/perf/util/probe-finder.c |   32 +++++++++++++++++++-------------
 1 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 9b0e1b1..32b81f7 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -686,6 +686,25 @@ static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
 	char buf[32], *ptr;
 	int ret, nscopes;
 
+	if (!is_c_varname(pf->pvar->var)) {
+		/* Copy raw parameters */
+		pf->tvar->value = strdup(pf->pvar->var);
+		if (pf->tvar->value == NULL)
+			return -ENOMEM;
+		if (pf->pvar->type) {
+			pf->tvar->type = strdup(pf->pvar->type);
+			if (pf->tvar->type == NULL)
+				return -ENOMEM;
+		}
+		if (pf->pvar->name) {
+			pf->tvar->name = strdup(pf->pvar->name);
+			if (pf->tvar->name == NULL)
+				return -ENOMEM;
+		} else
+			pf->tvar->name = NULL;
+		return 0;
+	}
+
 	if (pf->pvar->name)
 		pf->tvar->name = strdup(pf->pvar->name);
 	else {
@@ -700,19 +719,6 @@ static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
 	if (pf->tvar->name == NULL)
 		return -ENOMEM;
 
-	if (!is_c_varname(pf->pvar->var)) {
-		/* Copy raw parameters */
-		pf->tvar->value = strdup(pf->pvar->var);
-		if (pf->tvar->value == NULL)
-			return -ENOMEM;
-		if (pf->pvar->type) {
-			pf->tvar->type = strdup(pf->pvar->type);
-			if (pf->tvar->type == NULL)
-				return -ENOMEM;
-		}
-		return 0;
-	}
-
 	pr_debug("Searching '%s' variable in context.\n",
 		 pf->pvar->var);
 	/* Search child die for local variables and parameters. */

[PATCH -tip 4/5] tracing/kprobes: Set a name for each argument automatically

[Masami Hiramatsu]

Set "argN" name for each argument automatically if it has
no specified name. Since dynamic trace event(kprobe_events)
accepts special characters for its argument, its format
can show those special characters (e.g. '$', '%', '+').
However, perf can't parse those format because of the
character (especially '%') mess up the format.
This sets "argX" name for those arguments if user omitted
the argument names.

E.g.
 # echo 'p do_fork %ax IP=%ip $stack' > tracing/kprobe_events
 # cat tracing/kprobe_events
 p:kprobes/p_do_fork_0 do_fork arg1=%ax IP=%ip arg3=$stack

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reported-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: linux-kernel@vger.kernel.org
---

 kernel/trace/trace_kprobe.c |   17 ++++++++++-------
 1 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 0116c03..a39251e 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -997,15 +997,18 @@ static int create_trace_probe(int argc, char **argv)
 
 		/* Parse argument name */
 		arg = strchr(argv[i], '=');
-		if (arg)
+		if (arg) {
 			*arg++ = '\0';
-		else
+			tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);
+		} else {
 			arg = argv[i];
+			/* If argument name is omitted, set "argN" */
+			snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
+			tp->args[i].name = kstrdup(buf, GFP_KERNEL);
+		}
 
-		tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);
 		if (!tp->args[i].name) {
-			pr_info("Failed to allocate argument%d name '%s'.\n",
-				i, argv[i]);
+			pr_info("Failed to allocate argument[%d] name.\n", i);
 			ret = -ENOMEM;
 			goto error;
 		}
@@ -1014,7 +1017,7 @@ static int create_trace_probe(int argc, char **argv)
 			*tmp = '_';	/* convert : to _ */
 
 		if (conflict_field_name(tp->args[i].name, tp->args, i)) {
-			pr_info("Argument%d name '%s' conflicts with "
+			pr_info("Argument[%d] name '%s' conflicts with "
 				"another field.\n", i, argv[i]);
 			ret = -EINVAL;
 			goto error;
@@ -1023,7 +1026,7 @@ static int create_trace_probe(int argc, char **argv)
 		/* Parse fetch argument */
 		ret = parse_probe_arg(arg, tp, &tp->args[i], is_return);
 		if (ret) {
-			pr_info("Parse error at argument%d. (%d)\n", i, ret);
+			pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
 			goto error;
 		}
 	}

[PATCH -tip 5/5] tracing/kprobe: Check invalid argument name

[Masami Hiramatsu]

Check the argument name whether it is invalid (not C-like
symbol name). This makes event format simple.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reported-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: linux-kernel@vger.kernel.org
---

 kernel/trace/trace_kprobe.c |   20 ++++++++++++--------
 1 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index a39251e..544301d 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -514,8 +514,8 @@ static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
 				struct pt_regs *regs);
 
-/* Check the name is good for event/group */
-static int check_event_name(const char *name)
+/* Check the name is good for event/group/fields */
+static int is_good_name(const char *name)
 {
 	if (!isalpha(*name) && *name != '_')
 		return 0;
@@ -557,7 +557,7 @@ static struct trace_probe *alloc_trace_probe(const char *group,
 	else
 		tp->rp.kp.pre_handler = kprobe_dispatcher;
 
-	if (!event || !check_event_name(event)) {
+	if (!event || !is_good_name(event)) {
 		ret = -EINVAL;
 		goto error;
 	}
@@ -567,7 +567,7 @@ static struct trace_probe *alloc_trace_probe(const char *group,
 	if (!tp->call.name)
 		goto error;
 
-	if (!group || !check_event_name(group)) {
+	if (!group || !is_good_name(group)) {
 		ret = -EINVAL;
 		goto error;
 	}
@@ -883,7 +883,7 @@ static int create_trace_probe(int argc, char **argv)
 	int i, ret = 0;
 	int is_return = 0, is_delete = 0;
 	char *symbol = NULL, *event = NULL, *group = NULL;
-	char *arg, *tmp;
+	char *arg;
 	unsigned long offset = 0;
 	void *addr = NULL;
 	char buf[MAX_EVENT_NAME_LEN];
@@ -1012,9 +1012,13 @@ static int create_trace_probe(int argc, char **argv)
 			ret = -ENOMEM;
 			goto error;
 		}
-		tmp = strchr(tp->args[i].name, ':');
-		if (tmp)
-			*tmp = '_';	/* convert : to _ */
+
+		if (!is_good_name(tp->args[i].name)) {
+			pr_info("Invalid argument[%d] name: %s\n",
+				i, tp->args[i].name);
+			ret = -EINVAL;
+			goto error;
+		}
 
 		if (conflict_field_name(tp->args[i].name, tp->args, i)) {
 			pr_info("Argument[%d] name '%s' conflicts with "

[tip:perf/core] tracing/kprobe: Fix a memory leak in error case

[tip-bot for Masami Hiramatsu]

Commit-ID:  61a527362234ac3352a91ac67c50c6f7cd248eb1
Gitweb:     http://git.kernel.org/tip/61a527362234ac3352a91ac67c50c6f7cd248eb1
Author:     Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
AuthorDate: Fri, 27 Aug 2010 20:38:46 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Wed, 8 Sep 2010 11:47:18 -0300

tracing/kprobe: Fix a memory leak in error case

Fix a memory leak which happens when a field name conflicts with others. In
error case, free_trace_probe() will free all arguments until nr_args, so this
increments nr_args the begining of the loop instead of the end.

Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
LKML-Reference: <20100827113846.22882.12670.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 kernel/trace/trace_kprobe.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 8b27c98..0116c03 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -992,6 +992,9 @@ static int create_trace_probe(int argc, char **argv)
 	/* parse arguments */
 	ret = 0;
 	for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
+		/* Increment count for freeing args in error case */
+		tp->nr_args++;
+
 		/* Parse argument name */
 		arg = strchr(argv[i], '=');
 		if (arg)
@@ -1021,11 +1024,8 @@ static int create_trace_probe(int argc, char **argv)
 		ret = parse_probe_arg(arg, tp, &tp->args[i], is_return);
 		if (ret) {
 			pr_info("Parse error at argument%d. (%d)\n", i, ret);
-			kfree(tp->args[i].name);
 			goto error;
 		}
-
-		tp->nr_args++;
 	}
 
 	ret = register_trace_probe(tp);

[tip:perf/core] perf probe: Fix return probe support

[tip-bot for Masami Hiramatsu]

Commit-ID:  04ddd04b044d8896a4f8a921b23ba09d365df196
Gitweb:     http://git.kernel.org/tip/04ddd04b044d8896a4f8a921b23ba09d365df196
Author:     Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
AuthorDate: Fri, 27 Aug 2010 20:38:53 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Wed, 8 Sep 2010 11:47:18 -0300

perf probe: Fix return probe support

Fix a bug to support %return probe syntax again. Previous commit 4235b04 has a
bug which disables the %return syntax on perf probe.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20100827113852.22882.87447.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/probe-event.c  |    1 +
 tools/perf/util/probe-finder.c |   10 ++++++++++
 2 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index e72f05c..fcc16e4 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -1539,6 +1539,7 @@ static int convert_to_probe_trace_events(struct perf_probe_event *pev,
 		goto error;
 	}
 	tev->point.offset = pev->point.offset;
+	tev->point.retprobe = pev->point.retprobe;
 	tev->nargs = pev->nargs;
 	if (tev->nargs) {
 		tev->args = zalloc(sizeof(struct probe_trace_arg)
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 5251366..9b0e1b1 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -783,6 +783,16 @@ static int convert_probe_point(Dwarf_Die *sp_die, struct probe_finder *pf)
 		/* This function has no name. */
 		tev->point.offset = (unsigned long)pf->addr;
 
+	/* Return probe must be on the head of a subprogram */
+	if (pf->pev->point.retprobe) {
+		if (tev->point.offset != 0) {
+			pr_warning("Return probe must be on the head of"
+				   " a real function\n");
+			return -EINVAL;
+		}
+		tev->point.retprobe = true;
+	}
+
 	pr_debug("Probe point found: %s+%lu\n", tev->point.symbol,
 		 tev->point.offset);
 

[tip:perf/core] perf probe: Fix handling of arguments names

[tip-bot for Masami Hiramatsu]

Commit-ID:  367e94c10092469c896a226a77ef13cf6da757e4
Gitweb:     http://git.kernel.org/tip/367e94c10092469c896a226a77ef13cf6da757e4
Author:     Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
AuthorDate: Fri, 27 Aug 2010 20:38:59 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Wed, 8 Sep 2010 11:47:19 -0300

perf probe: Fix handling of arguments names

Don't make argument names from raw parameters (means the parameters are written
in kprobe-tracer syntax), because the argument syntax may include special
characters.  Just leave it, then kprobe-tracer gives a new name.

Reported-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20100827113859.22882.75598.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/probe-finder.c |   32 +++++++++++++++++++-------------
 1 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 9b0e1b1..32b81f7 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -686,6 +686,25 @@ static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
 	char buf[32], *ptr;
 	int ret, nscopes;
 
+	if (!is_c_varname(pf->pvar->var)) {
+		/* Copy raw parameters */
+		pf->tvar->value = strdup(pf->pvar->var);
+		if (pf->tvar->value == NULL)
+			return -ENOMEM;
+		if (pf->pvar->type) {
+			pf->tvar->type = strdup(pf->pvar->type);
+			if (pf->tvar->type == NULL)
+				return -ENOMEM;
+		}
+		if (pf->pvar->name) {
+			pf->tvar->name = strdup(pf->pvar->name);
+			if (pf->tvar->name == NULL)
+				return -ENOMEM;
+		} else
+			pf->tvar->name = NULL;
+		return 0;
+	}
+
 	if (pf->pvar->name)
 		pf->tvar->name = strdup(pf->pvar->name);
 	else {
@@ -700,19 +719,6 @@ static int find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
 	if (pf->tvar->name == NULL)
 		return -ENOMEM;
 
-	if (!is_c_varname(pf->pvar->var)) {
-		/* Copy raw parameters */
-		pf->tvar->value = strdup(pf->pvar->var);
-		if (pf->tvar->value == NULL)
-			return -ENOMEM;
-		if (pf->pvar->type) {
-			pf->tvar->type = strdup(pf->pvar->type);
-			if (pf->tvar->type == NULL)
-				return -ENOMEM;
-		}
-		return 0;
-	}
-
 	pr_debug("Searching '%s' variable in context.\n",
 		 pf->pvar->var);
 	/* Search child die for local variables and parameters. */

[tip:perf/core] tracing/kprobes: Fix handling of argument names

[tip-bot for Masami Hiramatsu]

Commit-ID:  aba91595cfcebd193425e20aabc407531526a1c5
Gitweb:     http://git.kernel.org/tip/aba91595cfcebd193425e20aabc407531526a1c5
Author:     Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
AuthorDate: Fri, 27 Aug 2010 20:39:06 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Wed, 8 Sep 2010 11:47:19 -0300

tracing/kprobes: Fix handling of argument names

Set "argN" name for each argument automatically if it has no specified name.
Since dynamic trace event(kprobe_events) accepts special characters for its
argument, its format can show those special characters (e.g. '$', '%', '+').
However, perf can't parse those format because of the character (especially
'%') mess up the format.  This sets "argX" name for those arguments if user
omitted the argument names.

E.g.
 # echo 'p do_fork %ax IP=%ip $stack' > tracing/kprobe_events
 # cat tracing/kprobe_events
 p:kprobes/p_do_fork_0 do_fork arg1=%ax IP=%ip arg3=$stack

Reported-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
LKML-Reference: <20100827113906.22882.59312.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 kernel/trace/trace_kprobe.c |   17 ++++++++++-------
 1 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 0116c03..a39251e 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -997,15 +997,18 @@ static int create_trace_probe(int argc, char **argv)
 
 		/* Parse argument name */
 		arg = strchr(argv[i], '=');
-		if (arg)
+		if (arg) {
 			*arg++ = '\0';
-		else
+			tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);
+		} else {
 			arg = argv[i];
+			/* If argument name is omitted, set "argN" */
+			snprintf(buf, MAX_EVENT_NAME_LEN, "arg%d", i + 1);
+			tp->args[i].name = kstrdup(buf, GFP_KERNEL);
+		}
 
-		tp->args[i].name = kstrdup(argv[i], GFP_KERNEL);
 		if (!tp->args[i].name) {
-			pr_info("Failed to allocate argument%d name '%s'.\n",
-				i, argv[i]);
+			pr_info("Failed to allocate argument[%d] name.\n", i);
 			ret = -ENOMEM;
 			goto error;
 		}
@@ -1014,7 +1017,7 @@ static int create_trace_probe(int argc, char **argv)
 			*tmp = '_';	/* convert : to _ */
 
 		if (conflict_field_name(tp->args[i].name, tp->args, i)) {
-			pr_info("Argument%d name '%s' conflicts with "
+			pr_info("Argument[%d] name '%s' conflicts with "
 				"another field.\n", i, argv[i]);
 			ret = -EINVAL;
 			goto error;
@@ -1023,7 +1026,7 @@ static int create_trace_probe(int argc, char **argv)
 		/* Parse fetch argument */
 		ret = parse_probe_arg(arg, tp, &tp->args[i], is_return);
 		if (ret) {
-			pr_info("Parse error at argument%d. (%d)\n", i, ret);
+			pr_info("Parse error at argument[%d]. (%d)\n", i, ret);
 			goto error;
 		}
 	}

[tip:perf/core] tracing/kprobe: Fix handling of C-unlike argument names

[tip-bot for Masami Hiramatsu]

Commit-ID:  da34634fd39958725310d2c30c9b4543945f968b
Gitweb:     http://git.kernel.org/tip/da34634fd39958725310d2c30c9b4543945f968b
Author:     Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
AuthorDate: Fri, 27 Aug 2010 20:39:12 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Wed, 8 Sep 2010 11:47:19 -0300

tracing/kprobe: Fix handling of C-unlike argument names

Check the argument name whether it is invalid (not C-like symbol name). This
makes event format simple.

Reported-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
LKML-Reference: <20100827113912.22882.62313.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 kernel/trace/trace_kprobe.c |   20 ++++++++++++--------
 1 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index a39251e..544301d 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -514,8 +514,8 @@ static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs);
 static int kretprobe_dispatcher(struct kretprobe_instance *ri,
 				struct pt_regs *regs);
 
-/* Check the name is good for event/group */
-static int check_event_name(const char *name)
+/* Check the name is good for event/group/fields */
+static int is_good_name(const char *name)
 {
 	if (!isalpha(*name) && *name != '_')
 		return 0;
@@ -557,7 +557,7 @@ static struct trace_probe *alloc_trace_probe(const char *group,
 	else
 		tp->rp.kp.pre_handler = kprobe_dispatcher;
 
-	if (!event || !check_event_name(event)) {
+	if (!event || !is_good_name(event)) {
 		ret = -EINVAL;
 		goto error;
 	}
@@ -567,7 +567,7 @@ static struct trace_probe *alloc_trace_probe(const char *group,
 	if (!tp->call.name)
 		goto error;
 
-	if (!group || !check_event_name(group)) {
+	if (!group || !is_good_name(group)) {
 		ret = -EINVAL;
 		goto error;
 	}
@@ -883,7 +883,7 @@ static int create_trace_probe(int argc, char **argv)
 	int i, ret = 0;
 	int is_return = 0, is_delete = 0;
 	char *symbol = NULL, *event = NULL, *group = NULL;
-	char *arg, *tmp;
+	char *arg;
 	unsigned long offset = 0;
 	void *addr = NULL;
 	char buf[MAX_EVENT_NAME_LEN];
@@ -1012,9 +1012,13 @@ static int create_trace_probe(int argc, char **argv)
 			ret = -ENOMEM;
 			goto error;
 		}
-		tmp = strchr(tp->args[i].name, ':');
-		if (tmp)
-			*tmp = '_';	/* convert : to _ */
+
+		if (!is_good_name(tp->args[i].name)) {
+			pr_info("Invalid argument[%d] name: %s\n",
+				i, tp->args[i].name);
+			ret = -EINVAL;
+			goto error;
+		}
 
 		if (conflict_field_name(tp->args[i].name, tp->args, i)) {
 			pr_info("Argument[%d] name '%s' conflicts with "