From: Steven Rostedt Date: Sat, 30 Apr 2011 02:35:33 +0000 (-0400) Subject: ftrace: Only update the function code on write to filter files X-Git-Tag: firefly_0821_release~10164^2~6^2~91 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=66e69865f32ed923518b80172d7c4595ce593683;p=firefly-linux-kernel-4.4.55.git ftrace: Only update the function code on write to filter files 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 Signed-off-by: Greg Kroah-Hartman --- diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 0afddc21b696..487293732a8a 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2360,14 +2360,16 @@ ftrace_regex_release(struct inode *inode, struct file *file, int enable) 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; }