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Subject[PATCH][GIT PULL] tracing: Fix regression of trace_options file setting
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Linus,

I just hit this bug with the lastest kernel. A change that came in this
merge window broke the writing to the trace_options file. It causes
garbage to be read during the compare of option names, and breaks
setting options via the trace_options file, although options can still
be set via the options/<option> files.

Also, I'm not sure where Ingo is, but I have an old pull request with
minor fixes. Feel free to pull that if you want too:

https://lkml.org/lkml/2013/1/7/208

Please pull trace-3.8-rc2-regression-fix:

git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
trace-3.8-rc2-regression-fix

Head SHA1: f1a67efdbc2c0acb43b2f844053320c38876776f


Steven Rostedt (1):
tracing: Fix regression of trace_options file setting

----
kernel/trace/trace.c | 2 ++
1 file changed, 2 insertions(+)
---------------------------
commit a8dd2176a8e988e3744e863ac39647a6f59fa900
Author: Steven Rostedt <srostedt@redhat.com>
Date: Wed Jan 9 20:54:17 2013 -0500

tracing: Fix regression of trace_options file setting

The latest change to allow trace options to be set on the command
line also broke the trace_options file.

The zeroing of the last byte of the option name that is echoed into
the trace_option file was removed with the consolidation of some
of the code. The compare between the option and what was written to
the trace_options file fails because the string holding the data
written doesn't terminate with a null character.

A zero needs to be added to the end of the string copied from
user space.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index e512567..1bbfa04 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2899,6 +2899,8 @@ tracing_trace_options_write(struct file *filp, const char __user *ubuf,
if (copy_from_user(&buf, ubuf, cnt))
return -EFAULT;

+ buf[cnt] = 0;
+
trace_set_options(buf);

*ppos += cnt;



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