[PATCH 00/18] tracing/kprobes: Update kprobes with new ftrace changes

[PATCH 00/18] tracing/kprobes: Update kprobes with new ftrace changes

[Steven Rostedt]

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Linus,

The majority of these changes are from Masami Hiramatsu bringing
kprobes up to par with the latest changes to ftrace (multi buffering
and the new function probes).

He also discovered and fixed some bugs in doing so. When pulling in his
patches, I also found a few minor bugs as well and fixed them.

This also includes a compile fix for some archs that select the ring buffer
but not tracing.

I based this off of the last patch you took from me that fixed the merge
conflict error, as that was the commit that had all the changes I needed
for this set of changes.


Please pull the latest trace-fixes-v3.10 tree, which can be found at:

  git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
trace-fixes-v3.10

Tag SHA1: b3955bf07072c5eb343b45faec09fee2d09cf695
Head SHA1: b8820084f2130b3dcfb09c78ac16cdd2194a345b


Masami Hiramatsu (11):
      tracing: Don't succeed if event_enable_func did not register anything
      ftrace, kprobes: Fix a deadlock on ftrace_regex_lock
      ftrace: Cleanup regex_lock and ftrace_lock around hash updating
      tracing/kprobes: Fix to increment return event probe hit-count
      tracing: Indicate enabled soft-mode in enable file
      tracing: Modify soft-mode only if there's no other referrer
      tracing/kprobes: Use bool for retprobe checker
      tracing/kprobes: Increment probe hit-count even if it is used by perf
      tracing/kprobes: Pass trace_probe directly from dispatcher
      tracing/kprobes: Support ftrace_event_file base multibuffer
      tracing/kprobes: Support soft-mode disabling

Steven Rostedt (Red Hat) (7):
      ring-buffer: Select IRQ_WORK
      tracing: Return error if register_ftrace_function_probe() fails for event_enable_func()
      ftrace: Have ftrace_regex_write() return either read or error
      tracing: Add helper function trace_create_new_event() to remove duplicate code
      ftrace: Fix locking in register_ftrace_function_probe()
      ftrace: Fix the output of enabled_functions debug file
      ftrace: Fix function probe when more than one probe is added

----
 include/linux/ftrace.h       |    4 +
 include/linux/ftrace_event.h |    1 +
 kernel/trace/Kconfig         |    2 +-
 kernel/trace/ftrace.c        |  126 ++++++++++++------
 kernel/trace/trace_events.c  |   54 ++++++--
 kernel/trace/trace_kprobe.c  |  289 ++++++++++++++++++++++++++++++++++--------
 6 files changed, 368 insertions(+), 108 deletions(-)

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[PATCH 01/18] ring-buffer: Select IRQ_WORK

[Steven Rostedt]

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From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

As the wake up logic for waiters on the buffer has been moved
from the tracing code to the ring buffer, it requires also adding
IRQ_WORK as the wake up code is performed via irq_work.

This fixes compile breakage when a user of the ring buffer is selected
but tracing and irq_work are not.

Link http://lkml.kernel.org/r/20130503115332.GT8356@rric.localhost

Cc: Arnd Bergmann <arnd@arndb.de>
Reported-by: Robert Richter <rric@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/Kconfig |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 5e9efd4..015f85a 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -71,6 +71,7 @@ config TRACE_CLOCK
 config RING_BUFFER
 	bool
 	select TRACE_CLOCK
+	select IRQ_WORK
 
 config FTRACE_NMI_ENTER
        bool
@@ -107,7 +108,6 @@ config TRACING
 	select BINARY_PRINTF
 	select EVENT_TRACING
 	select TRACE_CLOCK
-	select IRQ_WORK
 
 config GENERIC_TRACER
 	bool
-- 
1.7.10.4



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[PATCH 02/18] tracing: Dont succeed if event_enable_func did not register anything

[Steven Rostedt]

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From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Return 0 instead of the number of activated ftrace function probes if
event_enable_func succeeded and return an error code if it failed or
did not register any functions. But it currently returns the number
of registered functions and if it didn't register anything, it returns 0,
but that is considered success.

This also fixes the return value. As if it succeeds, it returns the
number of functions that were enabled, which is returned back to
the user in ftrace_regex_write (the write() return code). If only
one function is enabled, then the return code of the write is one,
and this can confuse the user program in thinking it only wrote 1
byte.

Link: http://lkml.kernel.org/r/20130509054413.30398.55650.stgit@mhiramat-M0-7522

Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <tom.zanussi@intel.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
[ Rewrote change log to reflect that this fixes two bugs - SR ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_events.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 53582e9..44ac836 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2061,8 +2061,11 @@ event_enable_func(struct ftrace_hash *hash,
 	if (ret < 0)
 		goto out_put;
 	ret = register_ftrace_function_probe(glob, ops, data);
-	if (!ret)
+	if (!ret) {
+		ret = -ENOENT;
 		goto out_disable;
+	} else
+		ret = 0;
  out:
 	mutex_unlock(&event_mutex);
 	return ret;
-- 
1.7.10.4



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[PATCH 03/18] tracing: Return error if register_ftrace_function_probe() fails for event_enable_func()

[Steven Rostedt]

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From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

register_ftrace_function_probe() returns the number of functions
it registered, which can be zero, it can also return a negative number
if something went wrong. But event_enable_func() only checks for
the case that it didn't register anything, it needs to also check
for the case that something went wrong and return that error code
as well.

Added some comments about the code as well, to make it more
understandable.

Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_events.c |   11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 44ac836..87e826f 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2061,11 +2061,18 @@ event_enable_func(struct ftrace_hash *hash,
 	if (ret < 0)
 		goto out_put;
 	ret = register_ftrace_function_probe(glob, ops, data);
+	/*
+	 * The above returns on success the # of functions enabled,
+	 * but if it didn't find any functions it returns zero.
+	 * Consider no functions a failure too.
+	 */
 	if (!ret) {
 		ret = -ENOENT;
 		goto out_disable;
-	} else
-		ret = 0;
+	} else if (ret < 0)
+		goto out_disable;
+	/* Just return zero, not the number of enabled functions */
+	ret = 0;
  out:
 	mutex_unlock(&event_mutex);
 	return ret;
-- 
1.7.10.4



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[PATCH 04/18] ftrace: Have ftrace_regex_write() return either read or error

[Steven Rostedt]

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From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

As ftrace_regex_write() reads the result of ftrace_process_regex()
which can sometimes return a positive number, only consider a
failure if the return is negative. Otherwise, it will skip possible
other registered probes and by returning a positive number that
wasn't read, it will confuse the user processes doing the writing.

Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 8a5c017..d85a0ad 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3276,7 +3276,7 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
 		ret = ftrace_process_regex(iter->hash, parser->buffer,
 					   parser->idx, enable);
 		trace_parser_clear(parser);
-		if (ret)
+		if (ret < 0)
 			goto out_unlock;
 	}
 
-- 
1.7.10.4



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[PATCH 05/18] ftrace, kprobes: Fix a deadlock on ftrace_regex_lock

[Steven Rostedt]

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From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Fix a deadlock on ftrace_regex_lock which happens when setting
an enable_event trigger on dynamic kprobe event as below.

----
sh-2.05b# echo p vfs_symlink > kprobe_events
sh-2.05b# echo vfs_symlink:enable_event:kprobes:p_vfs_symlink_0 > set_ftrace_filter

=============================================
[ INFO: possible recursive locking detected ]
3.9.0+ #35 Not tainted
---------------------------------------------
sh/72 is trying to acquire lock:
 (ftrace_regex_lock){+.+.+.}, at: [<ffffffff810ba6c1>] ftrace_set_hash+0x81/0x1f0

but task is already holding lock:
 (ftrace_regex_lock){+.+.+.}, at: [<ffffffff810b7cbd>] ftrace_regex_write.isra.29.part.30+0x3d/0x220

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(ftrace_regex_lock);
  lock(ftrace_regex_lock);

 *** DEADLOCK ***
----

To fix that, this introduces a finer regex_lock for each ftrace_ops.
ftrace_regex_lock is too big of a lock which protects all
filter/notrace_hash operations, but it doesn't need to be a global
lock after supporting multiple ftrace_ops because each ftrace_ops
has its own filter/notrace_hash.

Link: http://lkml.kernel.org/r/20130509054417.30398.84254.stgit@mhiramat-M0-7522

Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <tom.zanussi@intel.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
[ Added initialization flag and automate mutex initialization for
  non ftrace.c ftrace_probes. ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/linux/ftrace.h |    4 +++
 kernel/trace/ftrace.c  |   73 ++++++++++++++++++++++++++++++++++--------------
 2 files changed, 56 insertions(+), 21 deletions(-)

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index f83e17a..99d0fbc 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -90,6 +90,8 @@ typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip,
  *            not set this, then the ftrace infrastructure will add recursion
  *            protection for the caller.
  * STUB   - The ftrace_ops is just a place holder.
+ * INITIALIZED - The ftrace_ops has already been initialized (first use time
+ *            register_ftrace_function() is called, it will initialized the ops)
  */
 enum {
 	FTRACE_OPS_FL_ENABLED			= 1 << 0,
@@ -100,6 +102,7 @@ enum {
 	FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED	= 1 << 5,
 	FTRACE_OPS_FL_RECURSION_SAFE		= 1 << 6,
 	FTRACE_OPS_FL_STUB			= 1 << 7,
+	FTRACE_OPS_FL_INITIALIZED		= 1 << 8,
 };
 
 struct ftrace_ops {
@@ -110,6 +113,7 @@ struct ftrace_ops {
 #ifdef CONFIG_DYNAMIC_FTRACE
 	struct ftrace_hash		*notrace_hash;
 	struct ftrace_hash		*filter_hash;
+	struct mutex			regex_lock;
 #endif
 };
 
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index d85a0ad..827f2fe 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -64,6 +64,13 @@
 
 #define FL_GLOBAL_CONTROL_MASK (FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_CONTROL)
 
+#ifdef CONFIG_DYNAMIC_FTRACE
+#define INIT_REGEX_LOCK(opsname)	\
+	.regex_lock	= __MUTEX_INITIALIZER(opsname.regex_lock),
+#else
+#define INIT_REGEX_LOCK(opsname)
+#endif
+
 static struct ftrace_ops ftrace_list_end __read_mostly = {
 	.func		= ftrace_stub,
 	.flags		= FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
@@ -131,6 +138,16 @@ static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
 	while (likely(op = rcu_dereference_raw((op)->next)) &&	\
 	       unlikely((op) != &ftrace_list_end))
 
+static inline void ftrace_ops_init(struct ftrace_ops *ops)
+{
+#ifdef CONFIG_DYNAMIC_FTRACE
+	if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
+		mutex_init(&ops->regex_lock);
+		ops->flags |= FTRACE_OPS_FL_INITIALIZED;
+	}
+#endif
+}
+
 /**
  * ftrace_nr_registered_ops - return number of ops registered
  *
@@ -907,7 +924,8 @@ static void unregister_ftrace_profiler(void)
 #else
 static struct ftrace_ops ftrace_profile_ops __read_mostly = {
 	.func		= function_profile_call,
-	.flags		= FTRACE_OPS_FL_RECURSION_SAFE,
+	.flags		= FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
+	INIT_REGEX_LOCK(ftrace_profile_ops)
 };
 
 static int register_ftrace_profiler(void)
@@ -1103,11 +1121,10 @@ static struct ftrace_ops global_ops = {
 	.func			= ftrace_stub,
 	.notrace_hash		= EMPTY_HASH,
 	.filter_hash		= EMPTY_HASH,
-	.flags			= FTRACE_OPS_FL_RECURSION_SAFE,
+	.flags			= FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
+	INIT_REGEX_LOCK(global_ops)
 };
 
-static DEFINE_MUTEX(ftrace_regex_lock);
-
 struct ftrace_page {
 	struct ftrace_page	*next;
 	struct dyn_ftrace	*records;
@@ -1247,6 +1264,7 @@ static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
 
 void ftrace_free_filter(struct ftrace_ops *ops)
 {
+	ftrace_ops_init(ops);
 	free_ftrace_hash(ops->filter_hash);
 	free_ftrace_hash(ops->notrace_hash);
 }
@@ -2624,6 +2642,8 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag,
 	struct ftrace_hash *hash;
 	int ret = 0;
 
+	ftrace_ops_init(ops);
+
 	if (unlikely(ftrace_disabled))
 		return -ENODEV;
 
@@ -2656,7 +2676,7 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag,
 		}
 	}
 
-	mutex_lock(&ftrace_regex_lock);
+	mutex_lock(&ops->regex_lock);
 
 	if ((file->f_mode & FMODE_WRITE) &&
 	    (file->f_flags & O_TRUNC))
@@ -2677,7 +2697,7 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag,
 		}
 	} else
 		file->private_data = iter;
-	mutex_unlock(&ftrace_regex_lock);
+	mutex_unlock(&ops->regex_lock);
 
 	return ret;
 }
@@ -2910,6 +2930,8 @@ static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
 static struct ftrace_ops trace_probe_ops __read_mostly =
 {
 	.func		= function_trace_probe_call,
+	.flags		= FTRACE_OPS_FL_INITIALIZED,
+	INIT_REGEX_LOCK(trace_probe_ops)
 };
 
 static int ftrace_probe_registered;
@@ -3256,18 +3278,18 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
 	if (!cnt)
 		return 0;
 
-	mutex_lock(&ftrace_regex_lock);
-
-	ret = -ENODEV;
-	if (unlikely(ftrace_disabled))
-		goto out_unlock;
-
 	if (file->f_mode & FMODE_READ) {
 		struct seq_file *m = file->private_data;
 		iter = m->private;
 	} else
 		iter = file->private_data;
 
+	mutex_lock(&iter->ops->regex_lock);
+
+	ret = -ENODEV;
+	if (unlikely(ftrace_disabled))
+		goto out_unlock;
+
 	parser = &iter->parser;
 	read = trace_get_user(parser, ubuf, cnt, ppos);
 
@@ -3282,7 +3304,7 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
 
 	ret = read;
 out_unlock:
-	mutex_unlock(&ftrace_regex_lock);
+	mutex_unlock(&iter->ops->regex_lock);
 
 	return ret;
 }
@@ -3344,7 +3366,7 @@ ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
 	if (!hash)
 		return -ENOMEM;
 
-	mutex_lock(&ftrace_regex_lock);
+	mutex_lock(&ops->regex_lock);
 	if (reset)
 		ftrace_filter_reset(hash);
 	if (buf && !ftrace_match_records(hash, buf, len)) {
@@ -3366,7 +3388,7 @@ ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
 	mutex_unlock(&ftrace_lock);
 
  out_regex_unlock:
-	mutex_unlock(&ftrace_regex_lock);
+	mutex_unlock(&ops->regex_lock);
 
 	free_ftrace_hash(hash);
 	return ret;
@@ -3392,6 +3414,7 @@ ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
 			 int remove, int reset)
 {
+	ftrace_ops_init(ops);
 	return ftrace_set_addr(ops, ip, remove, reset, 1);
 }
 EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
@@ -3416,6 +3439,7 @@ ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
 		       int len, int reset)
 {
+	ftrace_ops_init(ops);
 	return ftrace_set_regex(ops, buf, len, reset, 1);
 }
 EXPORT_SYMBOL_GPL(ftrace_set_filter);
@@ -3434,6 +3458,7 @@ EXPORT_SYMBOL_GPL(ftrace_set_filter);
 int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
 			int len, int reset)
 {
+	ftrace_ops_init(ops);
 	return ftrace_set_regex(ops, buf, len, reset, 0);
 }
 EXPORT_SYMBOL_GPL(ftrace_set_notrace);
@@ -3524,6 +3549,8 @@ ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
 {
 	char *func;
 
+	ftrace_ops_init(ops);
+
 	while (buf) {
 		func = strsep(&buf, ",");
 		ftrace_set_regex(ops, func, strlen(func), 0, enable);
@@ -3551,14 +3578,14 @@ int ftrace_regex_release(struct inode *inode, struct file *file)
 	int filter_hash;
 	int ret;
 
-	mutex_lock(&ftrace_regex_lock);
 	if (file->f_mode & FMODE_READ) {
 		iter = m->private;
-
 		seq_release(inode, file);
 	} else
 		iter = file->private_data;
 
+	mutex_lock(&iter->ops->regex_lock);
+
 	parser = &iter->parser;
 	if (trace_parser_loaded(parser)) {
 		parser->buffer[parser->idx] = 0;
@@ -3587,7 +3614,7 @@ int ftrace_regex_release(struct inode *inode, struct file *file)
 	free_ftrace_hash(iter->hash);
 	kfree(iter);
 
-	mutex_unlock(&ftrace_regex_lock);
+	mutex_unlock(&iter->ops->regex_lock);
 	return 0;
 }
 
@@ -4126,7 +4153,8 @@ void __init ftrace_init(void)
 
 static struct ftrace_ops global_ops = {
 	.func			= ftrace_stub,
-	.flags			= FTRACE_OPS_FL_RECURSION_SAFE,
+	.flags			= FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
+	INIT_REGEX_LOCK(global_ops)
 };
 
 static int __init ftrace_nodyn_init(void)
@@ -4180,8 +4208,9 @@ ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip,
 }
 
 static struct ftrace_ops control_ops = {
-	.func = ftrace_ops_control_func,
-	.flags = FTRACE_OPS_FL_RECURSION_SAFE,
+	.func	= ftrace_ops_control_func,
+	.flags	= FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
+	INIT_REGEX_LOCK(control_ops)
 };
 
 static inline void
@@ -4539,6 +4568,8 @@ int register_ftrace_function(struct ftrace_ops *ops)
 {
 	int ret = -1;
 
+	ftrace_ops_init(ops);
+
 	mutex_lock(&ftrace_lock);
 
 	ret = __register_ftrace_function(ops);
-- 
1.7.10.4



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[PATCH 06/18] ftrace: Cleanup regex_lock and ftrace_lock around hash updating

[Steven Rostedt]

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From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Cleanup regex_lock and ftrace_lock locking points around
ftrace_ops hash update code.

The new rule is that regex_lock protects ops->*_hash
read-update-write code for each ftrace_ops. Usually,
hash update is done by following sequence.

1. allocate a new local hash and copy the original hash.
2. update the local hash.
3. move(actually, copy) back the local hash to ftrace_ops.
4. update ftrace entries if needed.
5. release the local hash.

This makes regex_lock protect #1-#4, and ftrace_lock
to protect #3, #4 and adding and removing ftrace_ops from the
ftrace_ops_list. The ftrace_lock protects #3 as well because
the move functions update the entries too.

Link: http://lkml.kernel.org/r/20130509054421.30398.83411.stgit@mhiramat-M0-7522

Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <tom.zanussi@intel.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c |   59 +++++++++++++++++++++++++++----------------------
 1 file changed, 32 insertions(+), 27 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 827f2fe..cacf085 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2656,28 +2656,26 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag,
 		return -ENOMEM;
 	}
 
+	iter->ops = ops;
+	iter->flags = flag;
+
+	mutex_lock(&ops->regex_lock);
+
 	if (flag & FTRACE_ITER_NOTRACE)
 		hash = ops->notrace_hash;
 	else
 		hash = ops->filter_hash;
 
-	iter->ops = ops;
-	iter->flags = flag;
-
 	if (file->f_mode & FMODE_WRITE) {
-		mutex_lock(&ftrace_lock);
 		iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash);
-		mutex_unlock(&ftrace_lock);
-
 		if (!iter->hash) {
 			trace_parser_put(&iter->parser);
 			kfree(iter);
-			return -ENOMEM;
+			ret = -ENOMEM;
+			goto out_unlock;
 		}
 	}
 
-	mutex_lock(&ops->regex_lock);
-
 	if ((file->f_mode & FMODE_WRITE) &&
 	    (file->f_flags & O_TRUNC))
 		ftrace_filter_reset(iter->hash);
@@ -2697,6 +2695,8 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag,
 		}
 	} else
 		file->private_data = iter;
+
+ out_unlock:
 	mutex_unlock(&ops->regex_lock);
 
 	return ret;
@@ -3012,7 +3012,7 @@ register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 	if (WARN_ON(not))
 		return -EINVAL;
 
-	mutex_lock(&ftrace_lock);
+	mutex_lock(&trace_probe_ops.regex_lock);
 
 	hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
 	if (!hash) {
@@ -3070,14 +3070,16 @@ register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 
 	} while_for_each_ftrace_rec();
 
+	mutex_lock(&ftrace_lock);
 	ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
 	if (ret < 0)
 		count = ret;
 
 	__enable_ftrace_function_probe();
+	mutex_unlock(&ftrace_lock);
 
  out_unlock:
-	mutex_unlock(&ftrace_lock);
+	mutex_unlock(&trace_probe_ops.regex_lock);
 	free_ftrace_hash(hash);
 
 	return count;
@@ -3117,7 +3119,7 @@ __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 			return;
 	}
 
-	mutex_lock(&ftrace_lock);
+	mutex_lock(&trace_probe_ops.regex_lock);
 
 	hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
 	if (!hash)
@@ -3155,6 +3157,7 @@ __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 			list_add(&entry->free_list, &free_list);
 		}
 	}
+	mutex_lock(&ftrace_lock);
 	__disable_ftrace_function_probe();
 	/*
 	 * Remove after the disable is called. Otherwise, if the last
@@ -3166,9 +3169,10 @@ __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 		list_del(&entry->free_list);
 		ftrace_free_entry(entry);
 	}
+	mutex_unlock(&ftrace_lock);
 		
  out_unlock:
-	mutex_unlock(&ftrace_lock);
+	mutex_unlock(&trace_probe_ops.regex_lock);
 	free_ftrace_hash(hash);
 }
 
@@ -3284,11 +3288,10 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
 	} else
 		iter = file->private_data;
 
-	mutex_lock(&iter->ops->regex_lock);
-
-	ret = -ENODEV;
 	if (unlikely(ftrace_disabled))
-		goto out_unlock;
+		return -ENODEV;
+
+	/* iter->hash is a local copy, so we don't need regex_lock */
 
 	parser = &iter->parser;
 	read = trace_get_user(parser, ubuf, cnt, ppos);
@@ -3299,13 +3302,11 @@ ftrace_regex_write(struct file *file, const char __user *ubuf,
 					   parser->idx, enable);
 		trace_parser_clear(parser);
 		if (ret < 0)
-			goto out_unlock;
+			goto out;
 	}
 
 	ret = read;
-out_unlock:
-	mutex_unlock(&iter->ops->regex_lock);
-
+ out:
 	return ret;
 }
 
@@ -3357,16 +3358,19 @@ ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
 	if (unlikely(ftrace_disabled))
 		return -ENODEV;
 
+	mutex_lock(&ops->regex_lock);
+
 	if (enable)
 		orig_hash = &ops->filter_hash;
 	else
 		orig_hash = &ops->notrace_hash;
 
 	hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
-	if (!hash)
-		return -ENOMEM;
+	if (!hash) {
+		ret = -ENOMEM;
+		goto out_regex_unlock;
+	}
 
-	mutex_lock(&ops->regex_lock);
 	if (reset)
 		ftrace_filter_reset(hash);
 	if (buf && !ftrace_match_records(hash, buf, len)) {
@@ -3584,8 +3588,6 @@ int ftrace_regex_release(struct inode *inode, struct file *file)
 	} else
 		iter = file->private_data;
 
-	mutex_lock(&iter->ops->regex_lock);
-
 	parser = &iter->parser;
 	if (trace_parser_loaded(parser)) {
 		parser->buffer[parser->idx] = 0;
@@ -3594,6 +3596,8 @@ int ftrace_regex_release(struct inode *inode, struct file *file)
 
 	trace_parser_put(parser);
 
+	mutex_lock(&iter->ops->regex_lock);
+
 	if (file->f_mode & FMODE_WRITE) {
 		filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
 
@@ -3611,10 +3615,11 @@ int ftrace_regex_release(struct inode *inode, struct file *file)
 
 		mutex_unlock(&ftrace_lock);
 	}
+
+	mutex_unlock(&iter->ops->regex_lock);
 	free_ftrace_hash(iter->hash);
 	kfree(iter);
 
-	mutex_unlock(&iter->ops->regex_lock);
 	return 0;
 }
 
-- 
1.7.10.4



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[PATCH 07/18] tracing/kprobes: Fix to increment return event probe hit-count

[Steven Rostedt]

[-- Attachment #1: Type: text/plain, Size: 1062 bytes --]

From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Fix to increment probe hit-count for function return event.

Link: http://lkml.kernel.org/r/20130509054424.30398.34058.stgit@mhiramat-M0-7522

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <tom.zanussi@intel.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_kprobe.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 1865d5f..6928633 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -767,6 +767,8 @@ static __kprobes void kretprobe_trace_func(struct kretprobe_instance *ri,
 	unsigned long irq_flags;
 	struct ftrace_event_call *call = &tp->call;
 
+	tp->nhit++;
+
 	local_save_flags(irq_flags);
 	pc = preempt_count();
 
-- 
1.7.10.4



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[PATCH 08/18] tracing: Indicate enabled soft-mode in enable file

[Steven Rostedt]

[-- Attachment #1: Type: text/plain, Size: 1213 bytes --]

From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Indicate enabled soft-mode event as "1*" in "enable" file
for each event, because it can be soft-disabled when disable_event
trigger is hit.

Link: http://lkml.kernel.org/r/20130509054426.30398.28202.stgit@mhiramat-M0-7522

Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <tom.zanussi@intel.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_events.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 87e826f..915c136 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -623,6 +623,8 @@ event_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
 	if (file->flags & FTRACE_EVENT_FL_ENABLED) {
 		if (file->flags & FTRACE_EVENT_FL_SOFT_DISABLED)
 			buf = "0*\n";
+		else if (file->flags & FTRACE_EVENT_FL_SOFT_MODE)
+			buf = "1*\n";
 		else
 			buf = "1\n";
 	} else
-- 
1.7.10.4



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[PATCH 09/18] tracing: Modify soft-mode only if theres no other referrer

[Steven Rostedt]

[-- Attachment #1: Type: text/plain, Size: 3890 bytes --]

From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Modify soft-mode flag only if no other soft-mode referrer
(currently only the ftrace triggers) by using a reference
counter in each ftrace_event_file.

Without this fix, adding and removing several different
enable/disable_event triggers on the same event clear
soft-mode bit from the ftrace_event_file. This also
happens with a typo of glob on setting triggers.

e.g.

 # echo vfs_symlink:enable_event:net:netif_rx > set_ftrace_filter
 # cat events/net/netif_rx/enable
 0*
 # echo typo_func:enable_event:net:netif_rx > set_ftrace_filter
 # cat events/net/netif_rx/enable
 0
 # cat set_ftrace_filter
 #### all functions enabled ####
 vfs_symlink:enable_event:net:netif_rx:unlimited

As above, we still have a trigger, but soft-mode is gone.

Link: http://lkml.kernel.org/r/20130509054429.30398.7464.stgit@mhiramat-M0-7522

Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: David Sharp <dhsharp@google.com>
Cc: Hiraku Toyooka <hiraku.toyooka.gu@hitachi.com>
Cc: Tom Zanussi <tom.zanussi@intel.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 include/linux/ftrace_event.h |    1 +
 kernel/trace/trace_events.c  |   12 ++++++++++--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 34e00fb..4372658 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -293,6 +293,7 @@ struct ftrace_event_file {
 	 * caching and such. Which is mostly OK ;-)
 	 */
 	unsigned long		flags;
+	atomic_t		sm_ref;	/* soft-mode reference counter */
 };
 
 #define __TRACE_EVENT_FLAGS(name, value)				\
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 915c136..8be1224 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -251,7 +251,8 @@ static int __ftrace_event_enable_disable(struct ftrace_event_file *file,
 	switch (enable) {
 	case 0:
 		/*
-		 * When soft_disable is set and enable is cleared, we want
+		 * When soft_disable is set and enable is cleared, the sm_ref
+		 * reference counter is decremented. If it reaches 0, we want
 		 * to clear the SOFT_DISABLED flag but leave the event in the
 		 * state that it was. That is, if the event was enabled and
 		 * SOFT_DISABLED isn't set, then do nothing. But if SOFT_DISABLED
@@ -263,6 +264,8 @@ static int __ftrace_event_enable_disable(struct ftrace_event_file *file,
 		 * "soft enable"s (clearing the SOFT_DISABLED bit) wont work.
 		 */
 		if (soft_disable) {
+			if (atomic_dec_return(&file->sm_ref) > 0)
+				break;
 			disable = file->flags & FTRACE_EVENT_FL_SOFT_DISABLED;
 			clear_bit(FTRACE_EVENT_FL_SOFT_MODE_BIT, &file->flags);
 		} else
@@ -291,8 +294,11 @@ static int __ftrace_event_enable_disable(struct ftrace_event_file *file,
 		 */
 		if (!soft_disable)
 			clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags);
-		else
+		else {
+			if (atomic_inc_return(&file->sm_ref) > 1)
+				break;
 			set_bit(FTRACE_EVENT_FL_SOFT_MODE_BIT, &file->flags);
+		}
 
 		if (!(file->flags & FTRACE_EVENT_FL_ENABLED)) {
 
@@ -1540,6 +1546,7 @@ __trace_add_new_event(struct ftrace_event_call *call,
 
 	file->event_call = call;
 	file->tr = tr;
+	atomic_set(&file->sm_ref, 0);
 	list_add(&file->list, &tr->events);
 
 	return event_create_dir(tr->event_dir, file, id, enable, filter, format);
@@ -1562,6 +1569,7 @@ __trace_early_add_new_event(struct ftrace_event_call *call,
 
 	file->event_call = call;
 	file->tr = tr;
+	atomic_set(&file->sm_ref, 0);
 	list_add(&file->list, &tr->events);
 
 	return 0;
-- 
1.7.10.4



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[PATCH 10/18] tracing: Add helper function trace_create_new_event() to remove duplicate code

[Steven Rostedt]

[-- Attachment #1: Type: text/plain, Size: 2333 bytes --]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

Both __trace_add_new_event() and __trace_early_add_new_event() do
basically the same thing, except that __trace_add_new_event() does
a little more.

Instead of having duplicate code between the two functions, add
a helper function trace_create_new_event() that both can use.
This will help against having bugs fixed in one function but not
the other.

Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_events.c |   32 ++++++++++++++++++++------------
 1 file changed, 20 insertions(+), 12 deletions(-)

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 8be1224..7a0cf68 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1529,6 +1529,24 @@ __register_event(struct ftrace_event_call *call, struct module *mod)
 	return 0;
 }
 
+static struct ftrace_event_file *
+trace_create_new_event(struct ftrace_event_call *call,
+		       struct trace_array *tr)
+{
+	struct ftrace_event_file *file;
+
+	file = kmem_cache_alloc(file_cachep, GFP_TRACE);
+	if (!file)
+		return NULL;
+
+	file->event_call = call;
+	file->tr = tr;
+	atomic_set(&file->sm_ref, 0);
+	list_add(&file->list, &tr->events);
+
+	return file;
+}
+
 /* Add an event to a trace directory */
 static int
 __trace_add_new_event(struct ftrace_event_call *call,
@@ -1540,15 +1558,10 @@ __trace_add_new_event(struct ftrace_event_call *call,
 {
 	struct ftrace_event_file *file;
 
-	file = kmem_cache_alloc(file_cachep, GFP_TRACE);
+	file = trace_create_new_event(call, tr);
 	if (!file)
 		return -ENOMEM;
 
-	file->event_call = call;
-	file->tr = tr;
-	atomic_set(&file->sm_ref, 0);
-	list_add(&file->list, &tr->events);
-
 	return event_create_dir(tr->event_dir, file, id, enable, filter, format);
 }
 
@@ -1563,15 +1576,10 @@ __trace_early_add_new_event(struct ftrace_event_call *call,
 {
 	struct ftrace_event_file *file;
 
-	file = kmem_cache_alloc(file_cachep, GFP_TRACE);
+	file = trace_create_new_event(call, tr);
 	if (!file)
 		return -ENOMEM;
 
-	file->event_call = call;
-	file->tr = tr;
-	atomic_set(&file->sm_ref, 0);
-	list_add(&file->list, &tr->events);
-
 	return 0;
 }
 
-- 
1.7.10.4



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[PATCH 11/18] ftrace: Fix locking in register_ftrace_function_probe()

[Steven Rostedt]

[-- Attachment #1: Type: text/plain, Size: 1458 bytes --]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

The iteration of the ftrace function list and the call to
ftrace_match_record() need to be protected by the ftrace_lock.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c |   10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index cacf085..f104c45 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3017,14 +3017,16 @@ register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 	hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
 	if (!hash) {
 		count = -ENOMEM;
-		goto out_unlock;
+		goto out;
 	}
 
 	if (unlikely(ftrace_disabled)) {
 		count = -ENODEV;
-		goto out_unlock;
+		goto out;
 	}
 
+	mutex_lock(&ftrace_lock);
+
 	do_for_each_ftrace_rec(pg, rec) {
 
 		if (!ftrace_match_record(rec, NULL, search, len, type))
@@ -3070,15 +3072,15 @@ register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 
 	} while_for_each_ftrace_rec();
 
-	mutex_lock(&ftrace_lock);
 	ret = ftrace_hash_move(&trace_probe_ops, 1, orig_hash, hash);
 	if (ret < 0)
 		count = ret;
 
 	__enable_ftrace_function_probe();
-	mutex_unlock(&ftrace_lock);
 
  out_unlock:
+	mutex_unlock(&ftrace_lock);
+ out:
 	mutex_unlock(&trace_probe_ops.regex_lock);
 	free_ftrace_hash(hash);
 
-- 
1.7.10.4



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[PATCH 12/18] ftrace: Fix the output of enabled_functions debug file

[Steven Rostedt]

[-- Attachment #1: Type: text/plain, Size: 1353 bytes --]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

The enabled_functions debugfs file was created to be able to see
what functions have been modified from nops to calling a tracer.

The current method uses the counter in the function record.
As when a ftrace_ops is registered to a function, its count
increases. But that doesn't mean that the function is actively
being traced. /proc/sys/kernel/ftrace_enabled can be set to zero
which would disable it, as well as something can go wrong and
we can think its enabled when only the counter is set.

The record's FTRACE_FL_ENABLED flag is set or cleared when its
function is modified. That is a much more accurate way of knowing
what function is enabled or not.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index f104c45..dcca9fa 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2459,7 +2459,7 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
 		     !ftrace_lookup_ip(ops->notrace_hash, rec->ip)) ||
 
 		    ((iter->flags & FTRACE_ITER_ENABLED) &&
-		     !(rec->flags & ~FTRACE_FL_MASK))) {
+		     !(rec->flags & FTRACE_FL_ENABLED))) {
 
 			rec = NULL;
 			goto retry;
-- 
1.7.10.4



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[PATCH 13/18] ftrace: Fix function probe when more than one probe is added

[Steven Rostedt]

[-- Attachment #1: Type: text/plain, Size: 3935 bytes --]

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

When the first function probe is added and the function tracer
is updated the functions are modified to call the probe.
But when a second function is added, it updates the function
records to have the second function also update, but it fails
to update the actual function itself.

This prevents the second (or third or forth and so on) probes
from having their functions called.

  # echo vfs_symlink:enable_event:sched:sched_switch > set_ftrace_filter
  # echo vfs_unlink:enable_event:sched:sched_switch > set_ftrace_filter
  # cat trace
 # tracer: nop
 #
 # entries-in-buffer/entries-written: 0/0   #P:4
 #
 #                              _-----=> irqs-off
 #                             / _----=> need-resched
 #                            | / _---=> hardirq/softirq
 #                            || / _--=> preempt-depth
 #                            ||| /     delay
 #           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
 #              | |       |   ||||       |         |
  # touch /tmp/a
  # rm /tmp/a
  # cat trace
 # tracer: nop
 #
 # entries-in-buffer/entries-written: 0/0   #P:4
 #
 #                              _-----=> irqs-off
 #                             / _----=> need-resched
 #                            | / _---=> hardirq/softirq
 #                            || / _--=> preempt-depth
 #                            ||| /     delay
 #           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
 #              | |       |   ||||       |         |
  # ln -s /tmp/a
  # cat trace
 # tracer: nop
 #
 # entries-in-buffer/entries-written: 414/414   #P:4
 #
 #                              _-----=> irqs-off
 #                             / _----=> need-resched
 #                            | / _---=> hardirq/softirq
 #                            || / _--=> preempt-depth
 #                            ||| /     delay
 #           TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
 #              | |       |   ||||       |         |
           <idle>-0     [000] d..3  2847.923031: sched_switch: prev_comm=swapper/0 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=bash next_pid=2786 next_prio=120
            <...>-3114  [001] d..4  2847.923035: sched_switch: prev_comm=ln prev_pid=3114 prev_prio=120 prev_state=x ==> next_comm=swapper/1 next_pid=0 next_prio=120
             bash-2786  [000] d..3  2847.923535: sched_switch: prev_comm=bash prev_pid=2786 prev_prio=120 prev_state=S ==> next_comm=kworker/0:1 next_pid=34 next_prio=120
      kworker/0:1-34    [000] d..3  2847.923552: sched_switch: prev_comm=kworker/0:1 prev_pid=34 prev_prio=120 prev_state=S ==> next_comm=swapper/0 next_pid=0 next_prio=120
           <idle>-0     [002] d..3  2847.923554: sched_switch: prev_comm=swapper/2 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=sshd next_pid=2783 next_prio=120
             sshd-2783  [002] d..3  2847.923660: sched_switch: prev_comm=sshd prev_pid=2783 prev_prio=120 prev_state=S ==> next_comm=swapper/2 next_pid=0 next_prio=120

Still need to update the functions even though the probe itself
does not need to be registered again when added a new probe.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index dcca9fa..b549b0f 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2941,8 +2941,12 @@ static void __enable_ftrace_function_probe(void)
 	int ret;
 	int i;
 
-	if (ftrace_probe_registered)
+	if (ftrace_probe_registered) {
+		/* still need to update the function call sites */
+		if (ftrace_enabled)
+			ftrace_run_update_code(FTRACE_UPDATE_CALLS);
 		return;
+	}
 
 	for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
 		struct hlist_head *hhd = &ftrace_func_hash[i];
-- 
1.7.10.4



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[PATCH 14/18] tracing/kprobes: Use bool for retprobe checker

[Steven Rostedt]

[-- Attachment #1: Type: text/plain, Size: 1076 bytes --]

From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Use bool instead of int for kretprobe checker.

Link: http://lkml.kernel.org/r/20130509054431.30398.38561.stgit@mhiramat-M0-7522

Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <tom.zanussi@intel.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_kprobe.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 6928633..0b7386a 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -46,7 +46,7 @@ struct trace_probe {
 	(sizeof(struct probe_arg) * (n)))
 
 
-static __kprobes int trace_probe_is_return(struct trace_probe *tp)
+static __kprobes bool trace_probe_is_return(struct trace_probe *tp)
 {
 	return tp->rp.handler != NULL;
 }
-- 
1.7.10.4



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[PATCH 15/18] tracing/kprobes: Increment probe hit-count even if it is used by perf

[Steven Rostedt]

[-- Attachment #1: Type: text/plain, Size: 1978 bytes --]

From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Increment probe hit-count for profiling even if it is used
by perf tool. Same thing has already done in trace_uprobe.

Link: http://lkml.kernel.org/r/20130509054436.30398.21133.stgit@mhiramat-M0-7522

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <tom.zanussi@intel.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_kprobe.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 0b7386a..6e86fbb 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -733,8 +733,6 @@ static __kprobes void kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
 	unsigned long irq_flags;
 	struct ftrace_event_call *call = &tp->call;
 
-	tp->nhit++;
-
 	local_save_flags(irq_flags);
 	pc = preempt_count();
 
@@ -767,8 +765,6 @@ static __kprobes void kretprobe_trace_func(struct kretprobe_instance *ri,
 	unsigned long irq_flags;
 	struct ftrace_event_call *call = &tp->call;
 
-	tp->nhit++;
-
 	local_save_flags(irq_flags);
 	pc = preempt_count();
 
@@ -1075,6 +1071,8 @@ int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
 {
 	struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
 
+	tp->nhit++;
+
 	if (tp->flags & TP_FLAG_TRACE)
 		kprobe_trace_func(kp, regs);
 #ifdef CONFIG_PERF_EVENTS
@@ -1089,6 +1087,8 @@ int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
 {
 	struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
 
+	tp->nhit++;
+
 	if (tp->flags & TP_FLAG_TRACE)
 		kretprobe_trace_func(ri, regs);
 #ifdef CONFIG_PERF_EVENTS
-- 
1.7.10.4



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[PATCH 16/18] tracing/kprobes: Pass trace_probe directly from dispatcher

[Steven Rostedt]

[-- Attachment #1: Type: text/plain, Size: 4632 bytes --]

From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Pass the pointer of struct trace_probe directly from probe
dispatcher to handlers. This removes redundant container_of
macro uses. Same thing has already done in trace_uprobe.

Link: http://lkml.kernel.org/r/20130509054441.30398.69112.stgit@mhiramat-M0-7522

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <tom.zanussi@intel.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_kprobe.c |   33 ++++++++++++++++-----------------
 1 file changed, 16 insertions(+), 17 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 6e86fbb..9ca44fc 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -723,9 +723,9 @@ static __kprobes void store_trace_args(int ent_size, struct trace_probe *tp,
 }
 
 /* Kprobe handler */
-static __kprobes void kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
+static __kprobes void
+kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs)
 {
-	struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
 	struct kprobe_trace_entry_head *entry;
 	struct ring_buffer_event *event;
 	struct ring_buffer *buffer;
@@ -745,7 +745,7 @@ static __kprobes void kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
 		return;
 
 	entry = ring_buffer_event_data(event);
-	entry->ip = (unsigned long)kp->addr;
+	entry->ip = (unsigned long)tp->rp.kp.addr;
 	store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
 
 	if (!filter_current_check_discard(buffer, call, entry, event))
@@ -754,10 +754,10 @@ static __kprobes void kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs)
 }
 
 /* Kretprobe handler */
-static __kprobes void kretprobe_trace_func(struct kretprobe_instance *ri,
-					  struct pt_regs *regs)
+static __kprobes void
+kretprobe_trace_func(struct trace_probe *tp, struct kretprobe_instance *ri,
+		     struct pt_regs *regs)
 {
-	struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
 	struct kretprobe_trace_entry_head *entry;
 	struct ring_buffer_event *event;
 	struct ring_buffer *buffer;
@@ -973,10 +973,9 @@ static int set_print_fmt(struct trace_probe *tp)
 #ifdef CONFIG_PERF_EVENTS
 
 /* Kprobe profile handler */
-static __kprobes void kprobe_perf_func(struct kprobe *kp,
-					 struct pt_regs *regs)
+static __kprobes void
+kprobe_perf_func(struct trace_probe *tp, struct pt_regs *regs)
 {
-	struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
 	struct ftrace_event_call *call = &tp->call;
 	struct kprobe_trace_entry_head *entry;
 	struct hlist_head *head;
@@ -995,7 +994,7 @@ static __kprobes void kprobe_perf_func(struct kprobe *kp,
 	if (!entry)
 		return;
 
-	entry->ip = (unsigned long)kp->addr;
+	entry->ip = (unsigned long)tp->rp.kp.addr;
 	memset(&entry[1], 0, dsize);
 	store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
 
@@ -1005,10 +1004,10 @@ static __kprobes void kprobe_perf_func(struct kprobe *kp,
 }
 
 /* Kretprobe profile handler */
-static __kprobes void kretprobe_perf_func(struct kretprobe_instance *ri,
-					    struct pt_regs *regs)
+static __kprobes void
+kretprobe_perf_func(struct trace_probe *tp, struct kretprobe_instance *ri,
+		    struct pt_regs *regs)
 {
-	struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
 	struct ftrace_event_call *call = &tp->call;
 	struct kretprobe_trace_entry_head *entry;
 	struct hlist_head *head;
@@ -1074,10 +1073,10 @@ int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs)
 	tp->nhit++;
 
 	if (tp->flags & TP_FLAG_TRACE)
-		kprobe_trace_func(kp, regs);
+		kprobe_trace_func(tp, regs);
 #ifdef CONFIG_PERF_EVENTS
 	if (tp->flags & TP_FLAG_PROFILE)
-		kprobe_perf_func(kp, regs);
+		kprobe_perf_func(tp, regs);
 #endif
 	return 0;	/* We don't tweek kernel, so just return 0 */
 }
@@ -1090,10 +1089,10 @@ int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs)
 	tp->nhit++;
 
 	if (tp->flags & TP_FLAG_TRACE)
-		kretprobe_trace_func(ri, regs);
+		kretprobe_trace_func(tp, ri, regs);
 #ifdef CONFIG_PERF_EVENTS
 	if (tp->flags & TP_FLAG_PROFILE)
-		kretprobe_perf_func(ri, regs);
+		kretprobe_perf_func(tp, ri, regs);
 #endif
 	return 0;	/* We don't tweek kernel, so just return 0 */
 }
-- 
1.7.10.4



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[PATCH 17/18] tracing/kprobes: Support ftrace_event_file base multibuffer

[Steven Rostedt]

[-- Attachment #1: Type: text/plain, Size: 12786 bytes --]

From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Support multi-buffer on kprobe-based dynamic events by
using ftrace_event_file.

Link: http://lkml.kernel.org/r/20130509054449.30398.88343.stgit@mhiramat-M0-7522

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <tom.zanussi@intel.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_kprobe.c |  250 ++++++++++++++++++++++++++++++++++++-------
 1 file changed, 214 insertions(+), 36 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 9ca44fc..fee865d 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -27,7 +27,6 @@
 /**
  * Kprobe event core functions
  */
-
 struct trace_probe {
 	struct list_head	list;
 	struct kretprobe	rp;	/* Use rp.kp for kprobe use */
@@ -36,6 +35,7 @@ struct trace_probe {
 	const char		*symbol;	/* symbol name */
 	struct ftrace_event_class	class;
 	struct ftrace_event_call	call;
+	struct ftrace_event_file	**files;
 	ssize_t			size;		/* trace entry size */
 	unsigned int		nr_args;
 	struct probe_arg	args[];
@@ -183,12 +183,57 @@ static struct trace_probe *find_trace_probe(const char *event,
 	return NULL;
 }
 
-/* Enable trace_probe - @flag must be TP_FLAG_TRACE or TP_FLAG_PROFILE */
-static int enable_trace_probe(struct trace_probe *tp, int flag)
+static int trace_probe_nr_files(struct trace_probe *tp)
+{
+	struct ftrace_event_file **file = tp->files;
+	int ret = 0;
+
+	if (file)
+		while (*(file++))
+			ret++;
+
+	return ret;
+}
+
+static DEFINE_MUTEX(probe_enable_lock);
+
+/*
+ * Enable trace_probe
+ * if the file is NULL, enable "perf" handler, or enable "trace" handler.
+ */
+static int
+enable_trace_probe(struct trace_probe *tp, struct ftrace_event_file *file)
 {
 	int ret = 0;
 
-	tp->flags |= flag;
+	mutex_lock(&probe_enable_lock);
+
+	if (file) {
+		struct ftrace_event_file **new, **old = tp->files;
+		int n = trace_probe_nr_files(tp);
+
+		/* 1 is for new one and 1 is for stopper */
+		new = kzalloc((n + 2) * sizeof(struct ftrace_event_file *),
+			      GFP_KERNEL);
+		if (!new) {
+			ret = -ENOMEM;
+			goto out_unlock;
+		}
+		memcpy(new, old, n * sizeof(struct ftrace_event_file *));
+		new[n] = file;
+		/* The last one keeps a NULL */
+
+		rcu_assign_pointer(tp->files, new);
+		tp->flags |= TP_FLAG_TRACE;
+
+		if (old) {
+			/* Make sure the probe is done with old files */
+			synchronize_sched();
+			kfree(old);
+		}
+	} else
+		tp->flags |= TP_FLAG_PROFILE;
+
 	if (trace_probe_is_enabled(tp) && trace_probe_is_registered(tp) &&
 	    !trace_probe_has_gone(tp)) {
 		if (trace_probe_is_return(tp))
@@ -197,19 +242,83 @@ static int enable_trace_probe(struct trace_probe *tp, int flag)
 			ret = enable_kprobe(&tp->rp.kp);
 	}
 
+ out_unlock:
+	mutex_unlock(&probe_enable_lock);
+
 	return ret;
 }
 
-/* Disable trace_probe - @flag must be TP_FLAG_TRACE or TP_FLAG_PROFILE */
-static void disable_trace_probe(struct trace_probe *tp, int flag)
+static int
+trace_probe_file_index(struct trace_probe *tp, struct ftrace_event_file *file)
+{
+	int i;
+
+	if (tp->files) {
+		for (i = 0; tp->files[i]; i++)
+			if (tp->files[i] == file)
+				return i;
+	}
+
+	return -1;
+}
+
+/*
+ * Disable trace_probe
+ * if the file is NULL, disable "perf" handler, or disable "trace" handler.
+ */
+static int
+disable_trace_probe(struct trace_probe *tp, struct ftrace_event_file *file)
 {
-	tp->flags &= ~flag;
+	int ret = 0;
+
+	mutex_lock(&probe_enable_lock);
+
+	if (file) {
+		struct ftrace_event_file **new, **old = tp->files;
+		int n = trace_probe_nr_files(tp);
+		int i, j;
+
+		if (n == 0 || trace_probe_file_index(tp, file) < 0) {
+			ret = -EINVAL;
+			goto out_unlock;
+		}
+
+		if (n == 1) {	/* Remove the last file */
+			tp->flags &= ~TP_FLAG_TRACE;
+			new = NULL;
+		} else {
+			new = kzalloc(n * sizeof(struct ftrace_event_file *),
+				      GFP_KERNEL);
+			if (!new) {
+				ret = -ENOMEM;
+				goto out_unlock;
+			}
+
+			/* This copy & check loop copies the NULL stopper too */
+			for (i = 0, j = 0; j < n && i < n + 1; i++)
+				if (old[i] != file)
+					new[j++] = old[i];
+		}
+
+		rcu_assign_pointer(tp->files, new);
+
+		/* Make sure the probe is done with old files */
+		synchronize_sched();
+		kfree(old);
+	} else
+		tp->flags &= ~TP_FLAG_PROFILE;
+
 	if (!trace_probe_is_enabled(tp) && trace_probe_is_registered(tp)) {
 		if (trace_probe_is_return(tp))
 			disable_kretprobe(&tp->rp);
 		else
 			disable_kprobe(&tp->rp.kp);
 	}
+
+ out_unlock:
+	mutex_unlock(&probe_enable_lock);
+
+	return ret;
 }
 
 /* Internal register function - just handle k*probes and flags */
@@ -724,7 +833,8 @@ static __kprobes void store_trace_args(int ent_size, struct trace_probe *tp,
 
 /* Kprobe handler */
 static __kprobes void
-kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs)
+__kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs,
+		    struct ftrace_event_file *ftrace_file)
 {
 	struct kprobe_trace_entry_head *entry;
 	struct ring_buffer_event *event;
@@ -733,14 +843,17 @@ kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs)
 	unsigned long irq_flags;
 	struct ftrace_event_call *call = &tp->call;
 
+	WARN_ON(call != ftrace_file->event_call);
+
 	local_save_flags(irq_flags);
 	pc = preempt_count();
 
 	dsize = __get_data_size(tp, regs);
 	size = sizeof(*entry) + tp->size + dsize;
 
-	event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
-						  size, irq_flags, pc);
+	event = trace_event_buffer_lock_reserve(&buffer, ftrace_file,
+						call->event.type,
+						size, irq_flags, pc);
 	if (!event)
 		return;
 
@@ -753,10 +866,23 @@ kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs)
 						irq_flags, pc, regs);
 }
 
+static __kprobes void
+kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs)
+{
+	struct ftrace_event_file **file = tp->files;
+
+	/* Note: preempt is already disabled around the kprobe handler */
+	while (*file) {
+		__kprobe_trace_func(tp, regs, *file);
+		file++;
+	}
+}
+
 /* Kretprobe handler */
 static __kprobes void
-kretprobe_trace_func(struct trace_probe *tp, struct kretprobe_instance *ri,
-		     struct pt_regs *regs)
+__kretprobe_trace_func(struct trace_probe *tp, struct kretprobe_instance *ri,
+		       struct pt_regs *regs,
+		       struct ftrace_event_file *ftrace_file)
 {
 	struct kretprobe_trace_entry_head *entry;
 	struct ring_buffer_event *event;
@@ -765,14 +891,17 @@ kretprobe_trace_func(struct trace_probe *tp, struct kretprobe_instance *ri,
 	unsigned long irq_flags;
 	struct ftrace_event_call *call = &tp->call;
 
+	WARN_ON(call != ftrace_file->event_call);
+
 	local_save_flags(irq_flags);
 	pc = preempt_count();
 
 	dsize = __get_data_size(tp, regs);
 	size = sizeof(*entry) + tp->size + dsize;
 
-	event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
-						  size, irq_flags, pc);
+	event = trace_event_buffer_lock_reserve(&buffer, ftrace_file,
+						call->event.type,
+						size, irq_flags, pc);
 	if (!event)
 		return;
 
@@ -786,6 +915,19 @@ kretprobe_trace_func(struct trace_probe *tp, struct kretprobe_instance *ri,
 						irq_flags, pc, regs);
 }
 
+static __kprobes void
+kretprobe_trace_func(struct trace_probe *tp, struct kretprobe_instance *ri,
+		     struct pt_regs *regs)
+{
+	struct ftrace_event_file **file = tp->files;
+
+	/* Note: preempt is already disabled around the kprobe handler */
+	while (*file) {
+		__kretprobe_trace_func(tp, ri, regs, *file);
+		file++;
+	}
+}
+
 /* Event entry printers */
 enum print_line_t
 print_kprobe_event(struct trace_iterator *iter, int flags,
@@ -1041,20 +1183,19 @@ int kprobe_register(struct ftrace_event_call *event,
 		    enum trace_reg type, void *data)
 {
 	struct trace_probe *tp = (struct trace_probe *)event->data;
+	struct ftrace_event_file *file = data;
 
 	switch (type) {
 	case TRACE_REG_REGISTER:
-		return enable_trace_probe(tp, TP_FLAG_TRACE);
+		return enable_trace_probe(tp, file);
 	case TRACE_REG_UNREGISTER:
-		disable_trace_probe(tp, TP_FLAG_TRACE);
-		return 0;
+		return disable_trace_probe(tp, file);
 
 #ifdef CONFIG_PERF_EVENTS
 	case TRACE_REG_PERF_REGISTER:
-		return enable_trace_probe(tp, TP_FLAG_PROFILE);
+		return enable_trace_probe(tp, NULL);
 	case TRACE_REG_PERF_UNREGISTER:
-		disable_trace_probe(tp, TP_FLAG_PROFILE);
-		return 0;
+		return disable_trace_probe(tp, NULL);
 	case TRACE_REG_PERF_OPEN:
 	case TRACE_REG_PERF_CLOSE:
 	case TRACE_REG_PERF_ADD:
@@ -1190,11 +1331,24 @@ static __used int kprobe_trace_selftest_target(int a1, int a2, int a3,
 	return a1 + a2 + a3 + a4 + a5 + a6;
 }
 
+static struct ftrace_event_file *
+find_trace_probe_file(struct trace_probe *tp, struct trace_array *tr)
+{
+	struct ftrace_event_file *file;
+
+	list_for_each_entry(file, &tr->events, list)
+		if (file->event_call == &tp->call)
+			return file;
+
+	return NULL;
+}
+
 static __init int kprobe_trace_self_tests_init(void)
 {
 	int ret, warn = 0;
 	int (*target)(int, int, int, int, int, int);
 	struct trace_probe *tp;
+	struct ftrace_event_file *file;
 
 	target = kprobe_trace_selftest_target;
 
@@ -1204,31 +1358,43 @@ static __init int kprobe_trace_self_tests_init(void)
 				  "$stack $stack0 +0($stack)",
 				  create_trace_probe);
 	if (WARN_ON_ONCE(ret)) {
-		pr_warning("error on probing function entry.\n");
+		pr_warn("error on probing function entry.\n");
 		warn++;
 	} else {
 		/* Enable trace point */
 		tp = find_trace_probe("testprobe", KPROBE_EVENT_SYSTEM);
 		if (WARN_ON_ONCE(tp == NULL)) {
-			pr_warning("error on getting new probe.\n");
+			pr_warn("error on getting new probe.\n");
 			warn++;
-		} else
-			enable_trace_probe(tp, TP_FLAG_TRACE);
+		} else {
+			file = find_trace_probe_file(tp, top_trace_array());
+			if (WARN_ON_ONCE(file == NULL)) {
+				pr_warn("error on getting probe file.\n");
+				warn++;
+			} else
+				enable_trace_probe(tp, file);
+		}
 	}
 
 	ret = traceprobe_command("r:testprobe2 kprobe_trace_selftest_target "
 				  "$retval", create_trace_probe);
 	if (WARN_ON_ONCE(ret)) {
-		pr_warning("error on probing function return.\n");
+		pr_warn("error on probing function return.\n");
 		warn++;
 	} else {
 		/* Enable trace point */
 		tp = find_trace_probe("testprobe2", KPROBE_EVENT_SYSTEM);
 		if (WARN_ON_ONCE(tp == NULL)) {
-			pr_warning("error on getting new probe.\n");
+			pr_warn("error on getting 2nd new probe.\n");
 			warn++;
-		} else
-			enable_trace_probe(tp, TP_FLAG_TRACE);
+		} else {
+			file = find_trace_probe_file(tp, top_trace_array());
+			if (WARN_ON_ONCE(file == NULL)) {
+				pr_warn("error on getting probe file.\n");
+				warn++;
+			} else
+				enable_trace_probe(tp, file);
+		}
 	}
 
 	if (warn)
@@ -1239,27 +1405,39 @@ static __init int kprobe_trace_self_tests_init(void)
 	/* Disable trace points before removing it */
 	tp = find_trace_probe("testprobe", KPROBE_EVENT_SYSTEM);
 	if (WARN_ON_ONCE(tp == NULL)) {
-		pr_warning("error on getting test probe.\n");
+		pr_warn("error on getting test probe.\n");
 		warn++;
-	} else
-		disable_trace_probe(tp, TP_FLAG_TRACE);
+	} else {
+		file = find_trace_probe_file(tp, top_trace_array());
+		if (WARN_ON_ONCE(file == NULL)) {
+			pr_warn("error on getting probe file.\n");
+			warn++;
+		} else
+			disable_trace_probe(tp, file);
+	}
 
 	tp = find_trace_probe("testprobe2", KPROBE_EVENT_SYSTEM);
 	if (WARN_ON_ONCE(tp == NULL)) {
-		pr_warning("error on getting 2nd test probe.\n");
+		pr_warn("error on getting 2nd test probe.\n");
 		warn++;
-	} else
-		disable_trace_probe(tp, TP_FLAG_TRACE);
+	} else {
+		file = find_trace_probe_file(tp, top_trace_array());
+		if (WARN_ON_ONCE(file == NULL)) {
+			pr_warn("error on getting probe file.\n");
+			warn++;
+		} else
+			disable_trace_probe(tp, file);
+	}
 
 	ret = traceprobe_command("-:testprobe", create_trace_probe);
 	if (WARN_ON_ONCE(ret)) {
-		pr_warning("error on deleting a probe.\n");
+		pr_warn("error on deleting a probe.\n");
 		warn++;
 	}
 
 	ret = traceprobe_command("-:testprobe2", create_trace_probe);
 	if (WARN_ON_ONCE(ret)) {
-		pr_warning("error on deleting a probe.\n");
+		pr_warn("error on deleting a probe.\n");
 		warn++;
 	}
 
-- 
1.7.10.4



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[PATCH 18/18] tracing/kprobes: Support soft-mode disabling

[Steven Rostedt]

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From: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Support soft-mode disabling on kprobe-based dynamic events.
Soft-disabling is just ignoring recording if the soft disabled
flag is set.

Link: http://lkml.kernel.org/r/20130509054454.30398.7237.stgit@mhiramat-M0-7522

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <tom.zanussi@intel.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_kprobe.c |    6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index fee865d..636d45f 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -845,6 +845,9 @@ __kprobe_trace_func(struct trace_probe *tp, struct pt_regs *regs,
 
 	WARN_ON(call != ftrace_file->event_call);
 
+	if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags))
+		return;
+
 	local_save_flags(irq_flags);
 	pc = preempt_count();
 
@@ -893,6 +896,9 @@ __kretprobe_trace_func(struct trace_probe *tp, struct kretprobe_instance *ri,
 
 	WARN_ON(call != ftrace_file->event_call);
 
+	if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags))
+		return;
+
 	local_save_flags(irq_flags);
 	pc = preempt_count();
 
-- 
1.7.10.4



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Re: [PATCH 00/18] tracing/kprobes: Update kprobes with new ftrace changes

[Linus Torvalds]

On Fri, May 10, 2013 at 5:12 PM, Steven Rostedt <rostedt@goodmis.org> wrote:
>
> Linus,
>
> The majority of these changes are from Masami Hiramatsu bringing
> kprobes up to par with the latest changes to ftrace (multi buffering
> and the new function probes).

So I pulled this just before doing -rc1, and I'm a bit worried about
"make allmodconfig" resulting in these new warnings:

   WARNING: "ring_buffer_event_data" [*/*/*.ko] has no CRC!

but the kernel I actually install and boot doesn't show that, so I
don't know if this then actually causes problems. And since I wasn't
going to do a kernel release tomorrow, I shipped -rc1 as-is.

Please do check it out and send me a fix, though.

                  Linus

Re: [PATCH 00/18] tracing/kprobes: Update kprobes with new ftrace changes

[Steven Rostedt]

On Sat, 2013-05-11 at 18:16 -0700, Linus Torvalds wrote:
> On Fri, May 10, 2013 at 5:12 PM, Steven Rostedt <rostedt@goodmis.org> wrote:
> >
> > Linus,
> >
> > The majority of these changes are from Masami Hiramatsu bringing
> > kprobes up to par with the latest changes to ftrace (multi buffering
> > and the new function probes).
> 
> So I pulled this just before doing -rc1, and I'm a bit worried about
> "make allmodconfig" resulting in these new warnings:
> 
>    WARNING: "ring_buffer_event_data" [*/*/*.ko] has no CRC!

I have no idea what that means. I found that line gets printed by
scripts/mod/modpost.c, but why it would print that for this is beyond
me. Note, the changes you pulled had nothing directly to do with that
function.

Here's the function in question:

void *ring_buffer_event_data(struct ring_buffer_event *event)
{
	return rb_event_data(event);
}
EXPORT_SYMBOL_GPL(ring_buffer_event_data);


> 
> but the kernel I actually install and boot doesn't show that, so I
> don't know if this then actually causes problems. And since I wasn't
> going to do a kernel release tomorrow, I shipped -rc1 as-is.

Yeah, I built, booted and tested an allmodconfig (as one of the ktests I
run), before sending you a pull request, so I didn't think it would be
an issue.

Although, I have to admit, I didn't look for new warnings on
allmodconfig. I do that check on other tests. I guess I should add a new
warning check for that test too. Although, as this is a warning from a
post compile program and not a gcc warning, my test will probably not
catch it.

> 
> Please do check it out and send me a fix, though.

I'm running an allmodconfig test now.

I see that function called near some of the changes in trace_kprobes.c:

        if (!event)
                return;
 
        entry = ring_buffer_event_data(event);
-       entry->ip = (unsigned long)kp->addr;
+       entry->ip = (unsigned long)tp->rp.kp.addr;
        store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
 
That's the only place I see it referenced in that last pull request. Not
sure why that would cause any issue.

I'll take a look when my allmodconfig test finishes.

-- Steve

Re: [PATCH 00/18] tracing/kprobes: Update kprobes with new ftrace changes

[Steven Rostedt]

On Sat, 2013-05-11 at 22:11 -0400, Steven Rostedt wrote:

> I'll take a look when my allmodconfig test finishes.

It just finished with no warnings about this. But I did it against the
branch you pulled, not to 3.10-rc1. I'll start that now.

-- Steve

Re: [PATCH 00/18] tracing/kprobes: Update kprobes with new ftrace changes

[Steven Rostedt]

On Sat, 2013-05-11 at 22:22 -0400, Steven Rostedt wrote:
> On Sat, 2013-05-11 at 22:11 -0400, Steven Rostedt wrote:
> 
> > I'll take a look when my allmodconfig test finishes.
> 
> It just finished with no warnings about this. But I did it against the
> branch you pulled, not to 3.10-rc1. I'll start that now.

Hmm, I'm still not able to reproduce this. Can you do a make mrproper
and rebuild and see if you still get that warning.

I'm trying a couple more things (like doing a make mrproper myself ;-).
I'm also building with an older 4.6 gcc. I wonder if the version of gcc
matters.

Thanks,

-- Steve

Re: [PATCH 00/18] tracing/kprobes: Update kprobes with new ftrace changes

[Linus Torvalds]

On Sun, May 12, 2013 at 5:50 AM, Steven Rostedt <rostedt@goodmis.org> wrote:
>
> Hmm, I'm still not able to reproduce this. Can you do a make mrproper
> and rebuild and see if you still get that warning.

Hmm. It *may* indicate some kind of build problem. The build I got
that for was an allmodconfig build, but I had interrupted the previous
one in the middle, because I wanted to re-do the build with the proper
version number. I wonder if there's some race where if you ^C the
build at just the right time the CRC's don't get done right?

Michal: any ideas? The errors are of the type:

   WARNING: "ring_buffer_event_data" [*/*/*.ko] has no CRC!

and maybe there's a problem with genksyms.c leaving an empty (or
incomplete) file around when interrupted, and it then gets reused the
next time around?

            Linus