| Date | Wed, 01 Jun 2011 16:59:03 +0900 | From | Greg KH <> | Subject | [007/146] ftrace: Only update the function code on write to filter files |
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2.6.38-stable review patch. If anyone has any objections, please let us know.
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From: Steven Rostedt <srostedt@redhat.com>
commit 058e297d34a404caaa5ed277de15698d8dc43000 upstream.
If function tracing is enabled, a read of the filter files will cause the call to stop_machine to update the function trace sites. It should only call stop_machine on write.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- kernel/trace/ftrace.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)
--- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2414,14 +2414,16 @@ ftrace_regex_release(struct inode *inode ftrace_match_records(parser->buffer, parser->idx, enable); } - mutex_lock(&ftrace_lock); - if (ftrace_start_up && ftrace_enabled) - ftrace_run_update_code(FTRACE_ENABLE_CALLS); - mutex_unlock(&ftrace_lock); - trace_parser_put(parser); kfree(iter); + if (file->f_mode & FMODE_WRITE) { + mutex_lock(&ftrace_lock); + if (ftrace_start_up && ftrace_enabled) + ftrace_run_update_code(FTRACE_ENABLE_CALLS); + mutex_unlock(&ftrace_lock); + } + mutex_unlock(&ftrace_regex_lock); return 0; }
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