[PATCH 1/3] tracing/ksym_tracer: fix the output of ksym tracer

[PATCH 1/3] tracing/ksym_tracer: fix the output of ksym tracer

[Xiao Guangrong]

Fix the output format of ksym tracer, make it properly aligned

Befor patch:
# tracer: ksym_tracer
#
#       TASK-PID      CPU#      Symbol         Type    Function         
#          |           |          |              |         |            
bash            1378  1   ksym_tracer_mutex     W  mutex_lock+0x11/0x27
bash            1378  1   ksym_filter_head      W  process_new_ksym_entry+0xd2/0x10c
bash            1378  1   ksym_tracer_mutex     W  mutex_unlock+0x12/0x1b
cat             1429  0   ksym_tracer_mutex     W  mutex_lock+0x11/0x27

After patch:
# tracer: ksym_tracer
#
#       TASK-PID   CPU#      Symbol                    Type    Function
#          |        |          |                        |         |
        cat-1423  [000] ksym_tracer_mutex               RW mutex_lock+0x11/0x27
        cat-1423  [000] ksym_filter_head                RW ksym_trace_filter_read+0x6e/0x10d
        cat-1423  [000] ksym_tracer_mutex               RW mutex_unlock+0x12/0x1b
        cat-1423  [000] ksym_tracer_mutex               RW mutex_lock+0x11/0x27
        cat-1423  [000] ksym_filter_head                RW ksym_trace_filter_read+0x6e/0x10d
        cat-1423  [000] ksym_tracer_mutex               RW mutex_unlock+0x12/0x1b

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
---
 kernel/trace/trace_ksym.c |   13 ++++++-------
 1 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/kernel/trace/trace_ksym.c b/kernel/trace/trace_ksym.c
index 1256a6e..fbf3a8e 100644
--- a/kernel/trace/trace_ksym.c
+++ b/kernel/trace/trace_ksym.c
@@ -370,13 +370,12 @@ static int ksym_trace_init(struct trace_array *tr)
 
 static void ksym_trace_print_header(struct seq_file *m)
 {
-
 	seq_puts(m,
-		 "#       TASK-PID      CPU#      Symbol         Type    "
-		 "Function         \n");
+		 "#       TASK-PID   CPU#      Symbol                    "
+		 "Type    Function\n");
 	seq_puts(m,
-		 "#          |           |          |              |         "
-		 "|            \n");
+		 "#          |        |          |                       "
+		 " |         |\n");
 }
 
 static enum print_line_t ksym_trace_output(struct trace_iterator *iter)
@@ -392,7 +391,7 @@ static enum print_line_t ksym_trace_output(struct trace_iterator *iter)
 
 	trace_assign_type(field, entry);
 
-	ret = trace_seq_printf(s, "%-15s %-5d %-3d %-20s ", field->cmd,
+	ret = trace_seq_printf(s, "%11s-%-5d [%03d] %-30s ", field->cmd,
 				entry->pid, iter->cpu, field->ksym_name);
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
@@ -412,7 +411,7 @@ static enum print_line_t ksym_trace_output(struct trace_iterator *iter)
 		return TRACE_TYPE_PARTIAL_LINE;
 
 	sprint_symbol(str, field->ip);
-	ret = trace_seq_printf(s, "%-20s\n", str);
+	ret = trace_seq_printf(s, "%s\n", str);
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 
-- 
1.6.1.2

[PATCH 2/3] tracing/ksym_tracer: fix write operation of ksym_trace_filter

[Xiao Guangrong]

This patch fix 2 bugs:
- fix the return value of ksym_trace_filter_write() when we want to
  clear symbol in ksym_trace_filter file
  for example:
  # echo global_trace:rw- > /debug/tracing/ksym_trace_filter
  # echo global_trace:--- > /debug/tracing/ksym_trace_filter
  -bash: echo: write error: Invalid argument
  # cat /debug/tracing/ksym_trace_filter
  #
  We want to clear 'global_trace' in ksym_trace_filter, it complain
  with "Invalid argument", but the operation is successful
  
- the "r--" access types is not allowed, but ksym_trace_filter file think
  it OK
  for example:
  # echo ksym_tracer_mutex:r-- > ksym_trace_filter
  -bash: echo: write error: Resource temporarily unavailable
  # dmesg
  ksym_tracer request failed. Try again later!!
  
  The error occur at register_kernel_hw_breakpoint(), but It's should
  at access types parser

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
---
 kernel/trace/trace_ksym.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/kernel/trace/trace_ksym.c b/kernel/trace/trace_ksym.c
index fbf3a8e..cd5cb65 100644
--- a/kernel/trace/trace_ksym.c
+++ b/kernel/trace/trace_ksym.c
@@ -135,6 +135,9 @@ static int ksym_trace_get_access_type(char *str)
 	case 6:
 		access = HW_BREAKPOINT_RW;
 		break;
+	case 4:
+		access = -EINVAL;
+		break;
 	case 2:
 		access = HW_BREAKPOINT_WRITE;
 		break;
@@ -312,6 +315,7 @@ static ssize_t ksym_trace_filter_write(struct file *file,
 		kfree(entry->ksym_hbp->info.name);
 		kfree(entry->ksym_hbp);
 		kfree(entry);
+		ret = 0;
 		goto out;
 	} else {
 		/* Check for malformed request: (4) */
-- 
1.6.1.2

[PATCH 3/3] tracing/ksym_tracer: support quick clear for ksym_trace_filter

[Xiao Guangrong]

It's rather bored to clear symbol one by one in ksym_trace_filter
file, so, this patch can let ksym_trace_filter file support quick
clear, we can write "0" to this file, it can clear all symbols
 
for example:
 # cat ksym_trace_filter
 ksym_filter_head:rw-
 global_trace:rw-
 # echo 0 > ksym_trace_filter
 # cat ksym_trace_filter
 #

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
---
 kernel/trace/trace_ksym.c |   45 +++++++++++++++++++++++++++------------------
 1 files changed, 27 insertions(+), 18 deletions(-)

diff --git a/kernel/trace/trace_ksym.c b/kernel/trace/trace_ksym.c
index cd5cb65..96b9e19 100644
--- a/kernel/trace/trace_ksym.c
+++ b/kernel/trace/trace_ksym.c
@@ -163,8 +163,6 @@ static int parse_ksym_trace_str(char *input_string, char **ksymname,
 {
 	int ret;
 
-	strstrip(input_string);
-
 	*ksymname = strsep(&input_string, ":");
 	*addr = kallsyms_lookup_name(*ksymname);
 
@@ -262,6 +260,25 @@ static ssize_t ksym_trace_filter_read(struct file *filp, char __user *ubuf,
 	return cnt;
 }
 
+static void __ksym_trace_reset(void)
+{
+	struct trace_ksym *entry;
+	struct hlist_node *node, *node1;
+
+	mutex_lock(&ksym_tracer_mutex);
+	hlist_for_each_entry_safe(entry, node, node1, &ksym_filter_head,
+								ksym_hlist) {
+		unregister_kernel_hw_breakpoint(entry->ksym_hbp);
+		ksym_filter_entry_count--;
+		hlist_del_rcu(&(entry->ksym_hlist));
+		synchronize_rcu();
+		kfree(entry->ksym_hbp->info.name);
+		kfree(entry->ksym_hbp);
+		kfree(entry);
+	}
+	mutex_unlock(&ksym_tracer_mutex);
+}
+
 static ssize_t ksym_trace_filter_write(struct file *file,
 					const char __user *buffer,
 						size_t count, loff_t *ppos)
@@ -282,6 +299,13 @@ static ssize_t ksym_trace_filter_write(struct file *file,
 	}
 	input_string[count] = '\0';
 
+	strstrip(input_string);
+	if (!strcmp(input_string, "0")) {
+		__ksym_trace_reset();
+		kfree(input_string);
+		return count;
+	}
+
 	ret = op = parse_ksym_trace_str(input_string, &ksymname, &ksym_addr);
 	if (ret < 0) {
 		kfree(input_string);
@@ -341,23 +365,8 @@ static const struct file_operations ksym_tracing_fops = {
 
 static void ksym_trace_reset(struct trace_array *tr)
 {
-	struct trace_ksym *entry;
-	struct hlist_node *node, *node1;
-
 	ksym_tracing_enabled = 0;
-
-	mutex_lock(&ksym_tracer_mutex);
-	hlist_for_each_entry_safe(entry, node, node1, &ksym_filter_head,
-								ksym_hlist) {
-		unregister_kernel_hw_breakpoint(entry->ksym_hbp);
-		ksym_filter_entry_count--;
-		hlist_del_rcu(&(entry->ksym_hlist));
-		synchronize_rcu();
-		kfree(entry->ksym_hbp->info.name);
-		kfree(entry->ksym_hbp);
-		kfree(entry);
-	}
-	mutex_unlock(&ksym_tracer_mutex);
+	__ksym_trace_reset();
 }
 
 static int ksym_trace_init(struct trace_array *tr)
-- 
1.6.1.2

Re: [PATCH 3/3] tracing/ksym_tracer: support quick clear for ksym_trace_filter

[K.Prasad]

On Wed, Jul 22, 2009 at 11:25:14AM +0800, Xiao Guangrong wrote:
> It's rather bored to clear symbol one by one in ksym_trace_filter
> file, so, this patch can let ksym_trace_filter file support quick
> clear, we can write "0" to this file, it can clear all symbols
> 
> for example:
>  # cat ksym_trace_filter
>  ksym_filter_head:rw-
>  global_trace:rw-
>  # echo 0 > ksym_trace_filter
>  # cat ksym_trace_filter
>  #
>

It's nice to have this feature added and the other patches fix issues in
ksym tracer. Can you have this patch add the capability to clear all
breakpoints in one-shot through wild-cards?

Ingo wanted something like "echo "*:---" > ksym_trace_filter". The patch
I sent here: http://lkml.org/lkml/2009/6/20/73 implements the same. You
may want to implement something on those lines.

Thanks,
K.Prasad

Re: [PATCH 3/3] tracing/ksym_tracer: support quick clear for ksym_trace_filter

[Xiao Guangrong]

K.Prasad wrote:
> On Wed, Jul 22, 2009 at 11:25:14AM +0800, Xiao Guangrong wrote:
>> It's rather bored to clear symbol one by one in ksym_trace_filter
>> file, so, this patch can let ksym_trace_filter file support quick
>> clear, we can write "0" to this file, it can clear all symbols
>>
>> for example:
>>  # cat ksym_trace_filter
>>  ksym_filter_head:rw-
>>  global_trace:rw-
>>  # echo 0 > ksym_trace_filter
>>  # cat ksym_trace_filter
>>  #
>>
> 
> It's nice to have this feature added and the other patches fix issues in
> ksym tracer. Can you have this patch add the capability to clear all
> breakpoints in one-shot through wild-cards?
> 

It already can clear all breakpoints in one-shot by write "0" to
ksym_trace_filter file, do you means that we need to support other
way for it? like:

echo > ksym_trace_filter
echo "*:---" > ksym_trace_filter

IMHO, one way to clear all breakpoints is enough, no need to add
more code for the same function, for example, in trace events filter,
only echo 0 > filter can properly clear all filters.

Are you sure other way is necessary? 

Thanks,
Xiao

> Ingo wanted something like "echo "*:---" > ksym_trace_filter". The patch
> I sent here: http://lkml.org/lkml/2009/6/20/73 implements the same. You
> may want to implement something on those lines.
> 
> Thanks,
> K.Prasad
> 
> 
> 

Re: [PATCH 3/3] tracing/ksym_tracer: support quick clear for ksym_trace_filter

[K.Prasad]

On Wed, Jul 22, 2009 at 05:56:49PM +0800, Xiao Guangrong wrote:
> 
> 
> K.Prasad wrote:
> > On Wed, Jul 22, 2009 at 11:25:14AM +0800, Xiao Guangrong wrote:
> >> It's rather bored to clear symbol one by one in ksym_trace_filter
> >> file, so, this patch can let ksym_trace_filter file support quick
> >> clear, we can write "0" to this file, it can clear all symbols
> >>
> >> for example:
> >>  # cat ksym_trace_filter
> >>  ksym_filter_head:rw-
> >>  global_trace:rw-
> >>  # echo 0 > ksym_trace_filter
> >>  # cat ksym_trace_filter
> >>  #
> >>
> > 
> > It's nice to have this feature added and the other patches fix issues in
> > ksym tracer. Can you have this patch add the capability to clear all
> > breakpoints in one-shot through wild-cards?
> > 
> 
> It already can clear all breakpoints in one-shot by write "0" to
> ksym_trace_filter file, do you means that we need to support other
> way for it? like:
> 
> echo > ksym_trace_filter
> echo "*:---" > ksym_trace_filter
> 
> IMHO, one way to clear all breakpoints is enough, no need to add
> more code for the same function, for example, in trace events filter,
> only echo 0 > filter can properly clear all filters.
> 
> Are you sure other way is necessary? 
> 
> Thanks,
> Xiao
>

As I stated before, the ability to support
echo "*:---" > ksym_trace_filter was Ingo Molnar's suggestion, so if
he's not particular about having it now we may skip it.

However, given that it requires just a few lines of code in addition,
say

+	/* Clear all breakpoints if echo "*:---" > ksym_trace_filter */
+	if ((strncmp(ksymname, "*", strlen("*")) == 0) && (op == 0)) {
+		ksym_trace_reset(NULL);
+		kfree(input_string);
+		return count;
+	}

in ksym_trace_filter_write(), and that the patch is already present it
shouldn't be bothersome to add it.

Thanks,
K.Prasad

Re: [PATCH 3/3] tracing/ksym_tracer: support quick clear for ksym_trace_filter

[Xiao Guangrong]

K.Prasad wrote:

> As I stated before, the ability to support
> echo "*:---" > ksym_trace_filter was Ingo Molnar's suggestion, so if
> he's not particular about having it now we may skip it.
> 

OK, I'll fix it.

> However, given that it requires just a few lines of code in addition,
> say
> 
> +	/* Clear all breakpoints if echo "*:---" > ksym_trace_filter */
> +	if ((strncmp(ksymname, "*", strlen("*")) == 0) && (op == 0)) {
> +		ksym_trace_reset(NULL);
> +		kfree(input_string);
> +		return count;
> +	}
> 

I think below way is simpler:

+	/*
+	/* Clear all breakpoints if:
+	/* 1: echo > ksym_trace_filter
+	/* 2: echo 0 > ksym_trace_filter
+	/* 3: echo "*:---" > ksym_trace_filter 
+	*/
+	strstrip(input_string);
+	if (!input_string[0] || !strcmp(input_string, "0") ||
+	   (!strcmp(input, "*:---")) {
+		__ksym_trace_reset();
+		kfree(input_string);
+		return count;
+	}
+

I'll sent a new patch after do some test for it.

Thanks,
Xiao

> in ksym_trace_filter_write(), and that the patch is already present it
> shouldn't be bothersome to add it.
> 
> Thanks,
> K.Prasad
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
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> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
> 
> 

[PATCH 3/3] tracing/ksym_tracer: support quick clear for ksym_trace_filter -- v2

[Xiao Guangrong]

It's rather bored to clear symbol one by one in ksym_trace_filter
file, so, this patch can let ksym_trace_filter file support quick
clear, we can write "0" to this file, it can clear all symbols
 
for example:
 # cat ksym_trace_filter
 ksym_filter_head:rw-
 global_trace:rw-
 # echo 0 > ksym_trace_filter
 # cat ksym_trace_filter
 #

Changelog v1->v2:
Add other way to clear all breakpoints by writing NULL or "*:---"
to ksym_trace_filter file base on K.Prasad's suggestion

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
---
 kernel/trace/trace_ksym.c |   53 +++++++++++++++++++++++++++++---------------
 1 files changed, 35 insertions(+), 18 deletions(-)

diff --git a/kernel/trace/trace_ksym.c b/kernel/trace/trace_ksym.c
index cd5cb65..2fde875 100644
--- a/kernel/trace/trace_ksym.c
+++ b/kernel/trace/trace_ksym.c
@@ -163,8 +163,6 @@ static int parse_ksym_trace_str(char *input_string, char **ksymname,
 {
 	int ret;
 
-	strstrip(input_string);
-
 	*ksymname = strsep(&input_string, ":");
 	*addr = kallsyms_lookup_name(*ksymname);
 
@@ -262,6 +260,25 @@ static ssize_t ksym_trace_filter_read(struct file *filp, char __user *ubuf,
 	return cnt;
 }
 
+static void __ksym_trace_reset(void)
+{
+	struct trace_ksym *entry;
+	struct hlist_node *node, *node1;
+
+	mutex_lock(&ksym_tracer_mutex);
+	hlist_for_each_entry_safe(entry, node, node1, &ksym_filter_head,
+								ksym_hlist) {
+		unregister_kernel_hw_breakpoint(entry->ksym_hbp);
+		ksym_filter_entry_count--;
+		hlist_del_rcu(&(entry->ksym_hlist));
+		synchronize_rcu();
+		kfree(entry->ksym_hbp->info.name);
+		kfree(entry->ksym_hbp);
+		kfree(entry);
+	}
+	mutex_unlock(&ksym_tracer_mutex);
+}
+
 static ssize_t ksym_trace_filter_write(struct file *file,
 					const char __user *buffer,
 						size_t count, loff_t *ppos)
@@ -282,6 +299,21 @@ static ssize_t ksym_trace_filter_write(struct file *file,
 	}
 	input_string[count] = '\0';
 
+	strstrip(input_string);
+
+	/*
+	 * Clear all breakpoints if:
+	 * 1: echo > ksym_trace_filter
+	 * 2: echo 0 > ksym_trace_filter
+	 * 3: echo "*:---" > ksym_trace_filter
+	 */
+	if (!input_string[0] || !strcmp(input_string, "0") ||
+	    !strcmp(input_string, "*:---")) {
+		__ksym_trace_reset();
+		kfree(input_string);
+		return count;
+	}
+
 	ret = op = parse_ksym_trace_str(input_string, &ksymname, &ksym_addr);
 	if (ret < 0) {
 		kfree(input_string);
@@ -341,23 +373,8 @@ static const struct file_operations ksym_tracing_fops = {
 
 static void ksym_trace_reset(struct trace_array *tr)
 {
-	struct trace_ksym *entry;
-	struct hlist_node *node, *node1;
-
 	ksym_tracing_enabled = 0;
-
-	mutex_lock(&ksym_tracer_mutex);
-	hlist_for_each_entry_safe(entry, node, node1, &ksym_filter_head,
-								ksym_hlist) {
-		unregister_kernel_hw_breakpoint(entry->ksym_hbp);
-		ksym_filter_entry_count--;
-		hlist_del_rcu(&(entry->ksym_hlist));
-		synchronize_rcu();
-		kfree(entry->ksym_hbp->info.name);
-		kfree(entry->ksym_hbp);
-		kfree(entry);
-	}
-	mutex_unlock(&ksym_tracer_mutex);
+	__ksym_trace_reset();
 }
 
 static int ksym_trace_init(struct trace_array *tr)
-- 
1.6.1.2

Re: [PATCH 3/3] tracing/ksym_tracer: support quick clear for ksym_trace_filter -- v2

[Steven Rostedt]

On Thu, 23 Jul 2009, Xiao Guangrong wrote:

> It's rather bored to clear symbol one by one in ksym_trace_filter
> file, so, this patch can let ksym_trace_filter file support quick
> clear, we can write "0" to this file, it can clear all symbols
>  
> for example:
>  # cat ksym_trace_filter
>  ksym_filter_head:rw-
>  global_trace:rw-
>  # echo 0 > ksym_trace_filter
>  # cat ksym_trace_filter
>  #
> 
> Changelog v1->v2:
> Add other way to clear all breakpoints by writing NULL or "*:---"
> to ksym_trace_filter file base on K.Prasad's suggestion

Thanks guys, I'll go ahead and queue this up for 32.

-- Steve

Re: [PATCH 3/3] tracing/ksym_tracer: support quick clear for ksym_trace_filter -- v2

[Xiao Guangrong]

Steven Rostedt wrote:
> 
> On Thu, 23 Jul 2009, Xiao Guangrong wrote:
> 
>> It's rather bored to clear symbol one by one in ksym_trace_filter
>> file, so, this patch can let ksym_trace_filter file support quick
>> clear, we can write "0" to this file, it can clear all symbols
>>  
>> for example:
>>  # cat ksym_trace_filter
>>  ksym_filter_head:rw-
>>  global_trace:rw-
>>  # echo 0 > ksym_trace_filter
>>  # cat ksym_trace_filter
>>  #
>>
>> Changelog v1->v2:
>> Add other way to clear all breakpoints by writing NULL or "*:---"
>> to ksym_trace_filter file base on K.Prasad's suggestion
> 
> Thanks guys, I'll go ahead and queue this up for 32.
> 

Hi Steven,

Could you have a look at other 2 patches in this series:

[PATCH 1/3] tracing/ksym_tracer: fix the output of ksym tracer
[PATCH 2/3] tracing/ksym_tracer: fix write operation of ksym_trace_filter

I think those fix is valuable, and K.Prasad has no objection.

Thanks,
Xiao

> -- Steve
> 
> 
> 

Re: [PATCH 3/3] tracing/ksym_tracer: support quick clear for ksym_trace_filter -- v2

[Steven Rostedt]

On Fri, 24 Jul 2009, Xiao Guangrong wrote:
> Steven Rostedt wrote:
> > 
> > On Thu, 23 Jul 2009, Xiao Guangrong wrote:
> > 
> >> It's rather bored to clear symbol one by one in ksym_trace_filter
> >> file, so, this patch can let ksym_trace_filter file support quick
> >> clear, we can write "0" to this file, it can clear all symbols
> >>  
> >> for example:
> >>  # cat ksym_trace_filter
> >>  ksym_filter_head:rw-
> >>  global_trace:rw-
> >>  # echo 0 > ksym_trace_filter
> >>  # cat ksym_trace_filter
> >>  #
> >>
> >> Changelog v1->v2:
> >> Add other way to clear all breakpoints by writing NULL or "*:---"
> >> to ksym_trace_filter file base on K.Prasad's suggestion
> > 
> > Thanks guys, I'll go ahead and queue this up for 32.
> > 
> 
> Hi Steven,
> 
> Could you have a look at other 2 patches in this series:
> 
> [PATCH 1/3] tracing/ksym_tracer: fix the output of ksym tracer
> [PATCH 2/3] tracing/ksym_tracer: fix write operation of ksym_trace_filter
> 
> I think those fix is valuable, and K.Prasad has no objection.

Ah, sorry for the confusion. I've queued up the entire series. I'm just 
playing with it now, and will post a pull request shortly.

-- Steve

[tip:perf/core] tracing/ksym_tracer: fix the output of ksym tracer

[tip-bot for Xiao Guangrong]

Commit-ID:  d857ace143df3884954887e1899a65831ca72ece
Gitweb:     http://git.kernel.org/tip/d857ace143df3884954887e1899a65831ca72ece
Author:     Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
AuthorDate: Wed, 22 Jul 2009 11:21:31 +0800
Committer:  Steven Rostedt <rostedt@goodmis.org>
CommitDate: Thu, 23 Jul 2009 20:51:35 -0400

tracing/ksym_tracer: fix the output of ksym tracer

Fix the output format of ksym tracer, make it properly aligned

Befor patch:
# tracer: ksym_tracer
#
#       TASK-PID      CPU#      Symbol         Type    Function
#          |           |          |              |         |
bash            1378  1   ksym_tracer_mutex     W  mutex_lock+0x11/0x27
bash            1378  1   ksym_filter_head      W  process_new_ksym_entry+0xd2/0x10c
bash            1378  1   ksym_tracer_mutex     W  mutex_unlock+0x12/0x1b
cat             1429  0   ksym_tracer_mutex     W  mutex_lock+0x11/0x27

After patch:
# tracer: ksym_tracer
#
#       TASK-PID   CPU#      Symbol                    Type    Function
#          |        |          |                        |         |
        cat-1423  [000] ksym_tracer_mutex               RW mutex_lock+0x11/0x27
        cat-1423  [000] ksym_filter_head                RW ksym_trace_filter_read+0x6e/0x10d
        cat-1423  [000] ksym_tracer_mutex               RW mutex_unlock+0x12/0x1b
        cat-1423  [000] ksym_tracer_mutex               RW mutex_lock+0x11/0x27
        cat-1423  [000] ksym_filter_head                RW ksym_trace_filter_read+0x6e/0x10d
        cat-1423  [000] ksym_tracer_mutex               RW mutex_unlock+0x12/0x1b

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
LKML-Reference: <4A6685BB.2090809@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_ksym.c |   13 ++++++-------
 1 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/kernel/trace/trace_ksym.c b/kernel/trace/trace_ksym.c
index 1256a6e..fbf3a8e 100644
--- a/kernel/trace/trace_ksym.c
+++ b/kernel/trace/trace_ksym.c
@@ -370,13 +370,12 @@ static int ksym_trace_init(struct trace_array *tr)
 
 static void ksym_trace_print_header(struct seq_file *m)
 {
-
 	seq_puts(m,
-		 "#       TASK-PID      CPU#      Symbol         Type    "
-		 "Function         \n");
+		 "#       TASK-PID   CPU#      Symbol                    "
+		 "Type    Function\n");
 	seq_puts(m,
-		 "#          |           |          |              |         "
-		 "|            \n");
+		 "#          |        |          |                       "
+		 " |         |\n");
 }
 
 static enum print_line_t ksym_trace_output(struct trace_iterator *iter)
@@ -392,7 +391,7 @@ static enum print_line_t ksym_trace_output(struct trace_iterator *iter)
 
 	trace_assign_type(field, entry);
 
-	ret = trace_seq_printf(s, "%-15s %-5d %-3d %-20s ", field->cmd,
+	ret = trace_seq_printf(s, "%11s-%-5d [%03d] %-30s ", field->cmd,
 				entry->pid, iter->cpu, field->ksym_name);
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
@@ -412,7 +411,7 @@ static enum print_line_t ksym_trace_output(struct trace_iterator *iter)
 		return TRACE_TYPE_PARTIAL_LINE;
 
 	sprint_symbol(str, field->ip);
-	ret = trace_seq_printf(s, "%-20s\n", str);
+	ret = trace_seq_printf(s, "%s\n", str);
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 

[tip:perf/core] tracing/ksym_tracer: fix write operation of ksym_trace_filter

[tip-bot for Xiao Guangrong]

Commit-ID:  8e068542a8d9efec55126284d2f5cb32f003d507
Gitweb:     http://git.kernel.org/tip/8e068542a8d9efec55126284d2f5cb32f003d507
Author:     Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
AuthorDate: Wed, 22 Jul 2009 11:23:41 +0800
Committer:  Steven Rostedt <rostedt@goodmis.org>
CommitDate: Thu, 23 Jul 2009 20:52:05 -0400

tracing/ksym_tracer: fix write operation of ksym_trace_filter

This patch fix 2 bugs:
- fix the return value of ksym_trace_filter_write() when we want to
  clear symbol in ksym_trace_filter file
  for example:
  # echo global_trace:rw- > /debug/tracing/ksym_trace_filter
  # echo global_trace:--- > /debug/tracing/ksym_trace_filter
  -bash: echo: write error: Invalid argument
  # cat /debug/tracing/ksym_trace_filter
  #
  We want to clear 'global_trace' in ksym_trace_filter, it complain
  with "Invalid argument", but the operation is successful

- the "r--" access types is not allowed, but ksym_trace_filter file think
  it OK
  for example:
  # echo ksym_tracer_mutex:r-- > ksym_trace_filter
  -bash: echo: write error: Resource temporarily unavailable
  # dmesg
  ksym_tracer request failed. Try again later!!

  The error occur at register_kernel_hw_breakpoint(), but It's should
  at access types parser

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
LKML-Reference: <4A66863D.5090802@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_ksym.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/kernel/trace/trace_ksym.c b/kernel/trace/trace_ksym.c
index fbf3a8e..cd5cb65 100644
--- a/kernel/trace/trace_ksym.c
+++ b/kernel/trace/trace_ksym.c
@@ -135,6 +135,9 @@ static int ksym_trace_get_access_type(char *str)
 	case 6:
 		access = HW_BREAKPOINT_RW;
 		break;
+	case 4:
+		access = -EINVAL;
+		break;
 	case 2:
 		access = HW_BREAKPOINT_WRITE;
 		break;
@@ -312,6 +315,7 @@ static ssize_t ksym_trace_filter_write(struct file *file,
 		kfree(entry->ksym_hbp->info.name);
 		kfree(entry->ksym_hbp);
 		kfree(entry);
+		ret = 0;
 		goto out;
 	} else {
 		/* Check for malformed request: (4) */

[tip:perf/core] tracing/ksym_tracer: support quick clear for ksym_trace_filter -- v2

[tip-bot for Xiao Guangrong]

Commit-ID:  75e33751ca8bbb72dd6f1a74d2810ddc8cbe4bdf
Gitweb:     http://git.kernel.org/tip/75e33751ca8bbb72dd6f1a74d2810ddc8cbe4bdf
Author:     Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
AuthorDate: Thu, 23 Jul 2009 12:01:22 +0800
Committer:  Steven Rostedt <rostedt@goodmis.org>
CommitDate: Thu, 23 Jul 2009 20:54:40 -0400

tracing/ksym_tracer: support quick clear for ksym_trace_filter -- v2

It's rather boring to clear symbol one by one in ksym_trace_filter
file, so, this patch will let ksym_trace_filter file support quickly
clear all break points. We can write "0" to this file and it will clear
all symbols

for example:
 # cat ksym_trace_filter
 ksym_filter_head:rw-
 global_trace:rw-
 # echo 0 > ksym_trace_filter
 # cat ksym_trace_filter
 #

Changelog v1->v2:
Add other ways to clear all breakpoints by writing NULL or "*:---"
to ksym_trace_filter file base on K.Prasad's suggestion

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
LKML-Reference: <4A67E092.3080202@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_ksym.c |   53 +++++++++++++++++++++++++++++---------------
 1 files changed, 35 insertions(+), 18 deletions(-)

diff --git a/kernel/trace/trace_ksym.c b/kernel/trace/trace_ksym.c
index cd5cb65..2fde875 100644
--- a/kernel/trace/trace_ksym.c
+++ b/kernel/trace/trace_ksym.c
@@ -163,8 +163,6 @@ static int parse_ksym_trace_str(char *input_string, char **ksymname,
 {
 	int ret;
 
-	strstrip(input_string);
-
 	*ksymname = strsep(&input_string, ":");
 	*addr = kallsyms_lookup_name(*ksymname);
 
@@ -262,6 +260,25 @@ static ssize_t ksym_trace_filter_read(struct file *filp, char __user *ubuf,
 	return cnt;
 }
 
+static void __ksym_trace_reset(void)
+{
+	struct trace_ksym *entry;
+	struct hlist_node *node, *node1;
+
+	mutex_lock(&ksym_tracer_mutex);
+	hlist_for_each_entry_safe(entry, node, node1, &ksym_filter_head,
+								ksym_hlist) {
+		unregister_kernel_hw_breakpoint(entry->ksym_hbp);
+		ksym_filter_entry_count--;
+		hlist_del_rcu(&(entry->ksym_hlist));
+		synchronize_rcu();
+		kfree(entry->ksym_hbp->info.name);
+		kfree(entry->ksym_hbp);
+		kfree(entry);
+	}
+	mutex_unlock(&ksym_tracer_mutex);
+}
+
 static ssize_t ksym_trace_filter_write(struct file *file,
 					const char __user *buffer,
 						size_t count, loff_t *ppos)
@@ -282,6 +299,21 @@ static ssize_t ksym_trace_filter_write(struct file *file,
 	}
 	input_string[count] = '\0';
 
+	strstrip(input_string);
+
+	/*
+	 * Clear all breakpoints if:
+	 * 1: echo > ksym_trace_filter
+	 * 2: echo 0 > ksym_trace_filter
+	 * 3: echo "*:---" > ksym_trace_filter
+	 */
+	if (!input_string[0] || !strcmp(input_string, "0") ||
+	    !strcmp(input_string, "*:---")) {
+		__ksym_trace_reset();
+		kfree(input_string);
+		return count;
+	}
+
 	ret = op = parse_ksym_trace_str(input_string, &ksymname, &ksym_addr);
 	if (ret < 0) {
 		kfree(input_string);
@@ -341,23 +373,8 @@ static const struct file_operations ksym_tracing_fops = {
 
 static void ksym_trace_reset(struct trace_array *tr)
 {
-	struct trace_ksym *entry;
-	struct hlist_node *node, *node1;
-
 	ksym_tracing_enabled = 0;
-
-	mutex_lock(&ksym_tracer_mutex);
-	hlist_for_each_entry_safe(entry, node, node1, &ksym_filter_head,
-								ksym_hlist) {
-		unregister_kernel_hw_breakpoint(entry->ksym_hbp);
-		ksym_filter_entry_count--;
-		hlist_del_rcu(&(entry->ksym_hlist));
-		synchronize_rcu();
-		kfree(entry->ksym_hbp->info.name);
-		kfree(entry->ksym_hbp);
-		kfree(entry);
-	}
-	mutex_unlock(&ksym_tracer_mutex);
+	__ksym_trace_reset();
 }
 
 static int ksym_trace_init(struct trace_array *tr)