From 6f3cf440470650b3841d325acacd0c5ea9504c68 Mon Sep 17 00:00:00 2001
From: Masami Hiramatsu <mhiramat@redhat.com>
Date: Wed, 16 Dec 2009 17:24:08 -0500
Subject: kprobe-tracer: Check new event/group name

Check new event/group name is same syntax as a C symbol. In other
words, checking the name is as like as other tracepoint events.

This can prevent user to create an event with useless name (e.g.
foo|bar, foo*bar).

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
LKML-Reference: <20091216222408.14459.68790.stgit@dhcp-100-2-132.bos.redhat.com>
[ v2: minor cleanups ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 kernel/trace/trace_kprobe.c | 31 +++++++++++++++++++++++++------
 1 file changed, 25 insertions(+), 6 deletions(-)

(limited to 'kernel/trace')

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 7ecab06547a5..375f81a568dc 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -282,6 +282,18 @@ 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)
+{
+	if (!isalpha(*name) && *name != '_')
+		return 0;
+	while (*++name != '\0') {
+		if (!isalpha(*name) && !isdigit(*name) && *name != '_')
+			return 0;
+	}
+	return 1;
+}
+
 /*
  * Allocate new trace_probe and initialize it (including kprobes).
  */
@@ -293,10 +305,11 @@ static struct trace_probe *alloc_trace_probe(const char *group,
 					     int nargs, int is_return)
 {
 	struct trace_probe *tp;
+	int ret = -ENOMEM;
 
 	tp = kzalloc(SIZEOF_TRACE_PROBE(nargs), GFP_KERNEL);
 	if (!tp)
-		return ERR_PTR(-ENOMEM);
+		return ERR_PTR(ret);
 
 	if (symbol) {
 		tp->symbol = kstrdup(symbol, GFP_KERNEL);
@@ -312,14 +325,20 @@ static struct trace_probe *alloc_trace_probe(const char *group,
 	else
 		tp->rp.kp.pre_handler = kprobe_dispatcher;
 
-	if (!event)
+	if (!event || !check_event_name(event)) {
+		ret = -EINVAL;
 		goto error;
+	}
+
 	tp->call.name = kstrdup(event, GFP_KERNEL);
 	if (!tp->call.name)
 		goto error;
 
-	if (!group)
+	if (!group || !check_event_name(group)) {
+		ret = -EINVAL;
 		goto error;
+	}
+
 	tp->call.system = kstrdup(group, GFP_KERNEL);
 	if (!tp->call.system)
 		goto error;
@@ -330,7 +349,7 @@ error:
 	kfree(tp->call.name);
 	kfree(tp->symbol);
 	kfree(tp);
-	return ERR_PTR(-ENOMEM);
+	return ERR_PTR(ret);
 }
 
 static void free_probe_arg(struct probe_arg *arg)
@@ -695,10 +714,10 @@ static int create_trace_probe(int argc, char **argv)
 	if (!event) {
 		/* Make a new event name */
 		if (symbol)
-			snprintf(buf, MAX_EVENT_NAME_LEN, "%c@%s%+ld",
+			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",
+			snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
 				 is_return ? 'r' : 'p', addr);
 		event = buf;
 	}
-- 
cgit v1.2.3


From 61c1917f47f73c968e92d04d15370b1dc3ec4592 Mon Sep 17 00:00:00 2001
From: Frederic Weisbecker <fweisbec@gmail.com>
Date: Thu, 17 Dec 2009 05:40:33 +0100
Subject: perf events, x86/stacktrace: Make stack walking optional

The current print_context_stack helper that does the stack
walking job is good for usual stacktraces as it walks through
all the stack and reports even addresses that look unreliable,
which is nice when we don't have frame pointers for example.

But we have users like perf that only require reliable
stacktraces, and those may want a more adapted stack walker, so
lets make this function a callback in stacktrace_ops that users
can tune for their needs.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1261024834-5336-1-git-send-regression-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/include/asm/stacktrace.h | 18 ++++++++++++++++++
 arch/x86/kernel/cpu/perf_event.c  |  1 +
 arch/x86/kernel/dumpstack.c       |  9 +++++----
 arch/x86/kernel/dumpstack.h       |  6 ------
 arch/x86/kernel/dumpstack_32.c    |  2 +-
 arch/x86/kernel/dumpstack_64.c    |  4 ++--
 arch/x86/kernel/stacktrace.c      | 18 ++++++++++--------
 arch/x86/oprofile/backtrace.c     |  9 +++++----
 kernel/trace/trace_sysprof.c      |  1 +
 9 files changed, 43 insertions(+), 25 deletions(-)

(limited to 'kernel/trace')

diff --git a/arch/x86/include/asm/stacktrace.h b/arch/x86/include/asm/stacktrace.h
index cf86a5e73815..6c75151a3cca 100644
--- a/arch/x86/include/asm/stacktrace.h
+++ b/arch/x86/include/asm/stacktrace.h
@@ -5,6 +5,23 @@ extern int kstack_depth_to_print;
 
 int x86_is_stack_id(int id, char *name);
 
+struct thread_info;
+struct stacktrace_ops;
+
+typedef unsigned long (*walk_stack_t)(struct thread_info *tinfo,
+				      unsigned long *stack,
+				      unsigned long bp,
+				      const struct stacktrace_ops *ops,
+				      void *data,
+				      unsigned long *end,
+				      int *graph);
+
+extern unsigned long
+print_context_stack(struct thread_info *tinfo,
+		    unsigned long *stack, unsigned long bp,
+		    const struct stacktrace_ops *ops, void *data,
+		    unsigned long *end, int *graph);
+
 /* Generic stack tracer with callbacks */
 
 struct stacktrace_ops {
@@ -14,6 +31,7 @@ struct stacktrace_ops {
 	void (*address)(void *data, unsigned long address, int reliable);
 	/* On negative return stop dumping */
 	int (*stack)(void *data, char *name);
+	walk_stack_t	walk_stack;
 };
 
 void dump_trace(struct task_struct *tsk, struct pt_regs *regs,
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 45506d5dd8df..d3802ee5a416 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -2336,6 +2336,7 @@ static const struct stacktrace_ops backtrace_ops = {
 	.warning_symbol		= backtrace_warning_symbol,
 	.stack			= backtrace_stack,
 	.address		= backtrace_address,
+	.walk_stack		= print_context_stack,
 };
 
 #include "../dumpstack.h"
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index 0a0aa1cec8f1..8aaa119b7cad 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -141,10 +141,11 @@ static void print_trace_address(void *data, unsigned long addr, int reliable)
 }
 
 static const struct stacktrace_ops print_trace_ops = {
-	.warning = print_trace_warning,
-	.warning_symbol = print_trace_warning_symbol,
-	.stack = print_trace_stack,
-	.address = print_trace_address,
+	.warning		= print_trace_warning,
+	.warning_symbol		= print_trace_warning_symbol,
+	.stack 			= print_trace_stack,
+	.address 		= print_trace_address,
+	.walk_stack		= print_context_stack,
 };
 
 void
diff --git a/arch/x86/kernel/dumpstack.h b/arch/x86/kernel/dumpstack.h
index 81086c227ab7..4fd1420faffa 100644
--- a/arch/x86/kernel/dumpstack.h
+++ b/arch/x86/kernel/dumpstack.h
@@ -14,12 +14,6 @@
 #define get_bp(bp) asm("movq %%rbp, %0" : "=r" (bp) :)
 #endif
 
-extern unsigned long
-print_context_stack(struct thread_info *tinfo,
-		unsigned long *stack, unsigned long bp,
-		const struct stacktrace_ops *ops, void *data,
-		unsigned long *end, int *graph);
-
 extern void
 show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
 		unsigned long *stack, unsigned long bp, char *log_lvl);
diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c
index e0ed4c7abb62..ae775ca47b25 100644
--- a/arch/x86/kernel/dumpstack_32.c
+++ b/arch/x86/kernel/dumpstack_32.c
@@ -58,7 +58,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
 
 		context = (struct thread_info *)
 			((unsigned long)stack & (~(THREAD_SIZE - 1)));
-		bp = print_context_stack(context, stack, bp, ops, data, NULL, &graph);
+		bp = ops->walk_stack(context, stack, bp, ops, data, NULL, &graph);
 
 		stack = (unsigned long *)context->previous_esp;
 		if (!stack)
diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index b13af53883aa..0ad9597073f5 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -188,8 +188,8 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
 			if (ops->stack(data, id) < 0)
 				break;
 
-			bp = print_context_stack(tinfo, stack, bp, ops,
-						 data, estack_end, &graph);
+			bp = ops->walk_stack(tinfo, stack, bp, ops,
+					     data, estack_end, &graph);
 			ops->stack(data, "<EOE>");
 			/*
 			 * We link to the next stack via the
diff --git a/arch/x86/kernel/stacktrace.c b/arch/x86/kernel/stacktrace.c
index c3eb207181fe..922eefbb3f6c 100644
--- a/arch/x86/kernel/stacktrace.c
+++ b/arch/x86/kernel/stacktrace.c
@@ -53,17 +53,19 @@ save_stack_address_nosched(void *data, unsigned long addr, int reliable)
 }
 
 static const struct stacktrace_ops save_stack_ops = {
-	.warning = save_stack_warning,
-	.warning_symbol = save_stack_warning_symbol,
-	.stack = save_stack_stack,
-	.address = save_stack_address,
+	.warning	= save_stack_warning,
+	.warning_symbol	= save_stack_warning_symbol,
+	.stack		= save_stack_stack,
+	.address	= save_stack_address,
+	.walk_stack	= print_context_stack,
 };
 
 static const struct stacktrace_ops save_stack_ops_nosched = {
-	.warning = save_stack_warning,
-	.warning_symbol = save_stack_warning_symbol,
-	.stack = save_stack_stack,
-	.address = save_stack_address_nosched,
+	.warning	= save_stack_warning,
+	.warning_symbol	= save_stack_warning_symbol,
+	.stack		= save_stack_stack,
+	.address	= save_stack_address_nosched,
+	.walk_stack	= print_context_stack,
 };
 
 /*
diff --git a/arch/x86/oprofile/backtrace.c b/arch/x86/oprofile/backtrace.c
index 044897be021f..3855096c59b8 100644
--- a/arch/x86/oprofile/backtrace.c
+++ b/arch/x86/oprofile/backtrace.c
@@ -41,10 +41,11 @@ static void backtrace_address(void *data, unsigned long addr, int reliable)
 }
 
 static struct stacktrace_ops backtrace_ops = {
-	.warning = backtrace_warning,
-	.warning_symbol = backtrace_warning_symbol,
-	.stack = backtrace_stack,
-	.address = backtrace_address,
+	.warning	= backtrace_warning,
+	.warning_symbol	= backtrace_warning_symbol,
+	.stack		= backtrace_stack,
+	.address	= backtrace_address,
+	.walk_stack	= print_context_stack,
 };
 
 struct frame_head {
diff --git a/kernel/trace/trace_sysprof.c b/kernel/trace/trace_sysprof.c
index f6693969287d..a7974a552ca9 100644
--- a/kernel/trace/trace_sysprof.c
+++ b/kernel/trace/trace_sysprof.c
@@ -93,6 +93,7 @@ static const struct stacktrace_ops backtrace_ops = {
 	.warning_symbol		= backtrace_warning_symbol,
 	.stack			= backtrace_stack,
 	.address		= backtrace_address,
+	.walk_stack		= print_context_stack,
 };
 
 static int
-- 
cgit v1.2.3