[PATCH 0/2] [GIT PULL] tracing: various fixes

[PATCH 0/2] [GIT PULL] tracing: various fixes

[Steven Rostedt]

Ingo,

These two patches are built against my last push, but perhaps these
should go to 2.6.31. The first one fixes a bug that makes the 
printk_format file useless (making trace_bprintk useless for binary
readers). The other is a bug with the way the files may be truncated
incorrectly.

Please pull the latest tip/tracing/core-1 tree, which can be found at:

  git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace.git
tip/tracing/core-1


Steven Rostedt (2):
      tracing: show proper address for trace-printk format
      tracing: only truncate ftrace files when O_TRUNC is set

----
 kernel/trace/ftrace.c       |    4 ++--
 kernel/trace/trace.c        |    2 +-
 kernel/trace/trace_events.c |    2 +-
 kernel/trace/trace_printk.c |    2 +-
 4 files changed, 5 insertions(+), 5 deletions(-)
-- 

[PATCH 1/2] tracing: show proper address for trace-printk format

[Steven Rostedt]

[-- Attachment #1: 0001-tracing-show-proper-address-for-trace-printk-format.patch --]
[-- Type: text/plain, Size: 1202 bytes --]

From: Steven Rostedt <srostedt@redhat.com>

Since the trace_printk may use pointers to the format fields
in the buffer, they are exported via debugfs/tracing/printk_formats.
This is used by utilities that read the ring buffer in binary format.
It helps the utilities map the address of the format in the binary
buffer to what the printf format looks like.

Unfortunately, the way the output code works, it exports the address
of the pointer to the format address, and not the format address
itself. This makes the file totally useless in trying to figure
out what format string a binary address belongs to.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/trace_printk.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c
index 7b62781..687699d 100644
--- a/kernel/trace/trace_printk.c
+++ b/kernel/trace/trace_printk.c
@@ -176,7 +176,7 @@ static int t_show(struct seq_file *m, void *v)
 	const char *str = *fmt;
 	int i;
 
-	seq_printf(m, "0x%lx : \"", (unsigned long)fmt);
+	seq_printf(m, "0x%lx : \"", *(unsigned long *)fmt);
 
 	/*
 	 * Tabs and new lines need to be converted.
-- 
1.6.3.3

-- 

[PATCH 2/2] tracing: only truncate ftrace files when O_TRUNC is set

[Steven Rostedt]

[-- Attachment #1: 0002-tracing-only-truncate-ftrace-files-when-O_TRUNC-is-s.patch --]
[-- Type: text/plain, Size: 2324 bytes --]

From: Steven Rostedt <srostedt@redhat.com>

The current code will truncate the ftrace files contents if O_APPEND
is not set and the file is opened in write mode. This is incorrect.
It should only truncate the file if O_TRUNC is set. Otherwise
if one of these files is opened by a C program with fopen "r+",
it will incorrectly truncate the file.

Reported-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/trace/ftrace.c       |    4 ++--
 kernel/trace/trace.c        |    2 +-
 kernel/trace/trace_events.c |    2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 24e3ff5..bb6b566 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1617,7 +1617,7 @@ ftrace_regex_open(struct inode *inode, struct file *file, int enable)
 
 	mutex_lock(&ftrace_regex_lock);
 	if ((file->f_mode & FMODE_WRITE) &&
-	    !(file->f_flags & O_APPEND))
+	    (file->f_flags & O_TRUNC))
 		ftrace_filter_reset(enable);
 
 	if (file->f_mode & FMODE_READ) {
@@ -2527,7 +2527,7 @@ ftrace_graph_open(struct inode *inode, struct file *file)
 
 	mutex_lock(&graph_lock);
 	if ((file->f_mode & FMODE_WRITE) &&
-	    !(file->f_flags & O_APPEND)) {
+	    (file->f_flags & O_TRUNC)) {
 		ftrace_graph_count = 0;
 		memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
 	}
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 38a4a3e..3a522a0 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2031,7 +2031,7 @@ static int tracing_open(struct inode *inode, struct file *file)
 
 	/* If this file was open for write, then erase contents */
 	if ((file->f_mode & FMODE_WRITE) &&
-	    !(file->f_flags & O_APPEND)) {
+	    (file->f_flags & O_TRUNC)) {
 		long cpu = (long) inode->i_private;
 
 		if (cpu == TRACE_PIPE_ALL_CPU)
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 90cf936..90cdec5 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -378,7 +378,7 @@ ftrace_event_seq_open(struct inode *inode, struct file *file)
 	const struct seq_operations *seq_ops;
 
 	if ((file->f_mode & FMODE_WRITE) &&
-	    !(file->f_flags & O_APPEND))
+	    (file->f_flags & O_TRUNC))
 		ftrace_clear_events();
 
 	seq_ops = inode->i_private;
-- 
1.6.3.3

-- 

Re: [PATCH 0/2] [GIT PULL] tracing: various fixes

[Steven Rostedt]

On Wed, 22 Jul 2009, Steven Rostedt wrote:

> 
> Ingo,
> 
> These two patches are built against my last push, but perhaps these
> should go to 2.6.31. The first one fixes a bug that makes the 
> printk_format file useless (making trace_bprintk useless for binary
> readers). The other is a bug with the way the files may be truncated
> incorrectly.

I may pull these over to urgent. They probably should go into 31.

I'll make another pull request there instead.

Thanks,

-- Steve

> 
> Please pull the latest tip/tracing/core-1 tree, which can be found at:
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace.git
> tip/tracing/core-1
> 
> 
> Steven Rostedt (2):
>       tracing: show proper address for trace-printk format
>       tracing: only truncate ftrace files when O_TRUNC is set
> 
> ----
>  kernel/trace/ftrace.c       |    4 ++--
>  kernel/trace/trace.c        |    2 +-
>  kernel/trace/trace_events.c |    2 +-
>  kernel/trace/trace_printk.c |    2 +-
>  4 files changed, 5 insertions(+), 5 deletions(-)
> -- 
>