On Tue, 06 Feb 2018 17:43:40 -0500 Steven Rostedt rostedt@goodmis.org wrote:

From: "Steven Rostedt (VMware)" rostedt@goodmis.org

Al Viro reported:

For substring - sure, but what about something like "*a*b" and "a*b"?
AFAICS, filter_parse_regex() ends up with identical results in both
cases - MATCH_GLOB and *search = "a*b".  And no way for the caller
to tell one from another.

Testing this with the following:

# cd /sys/kernel/tracing # echo '*raw*lock' > set_ftrace_filter bash: echo: write error: Invalid argument

With this patch:

# echo '*raw*lock' > set_ftrace_filter # cat set_ftrace_filter _raw_read_trylock _raw_write_trylock _raw_read_unlock _raw_spin_unlock _raw_write_unlock _raw_spin_trylock _raw_spin_lock _raw_write_lock _raw_read_lock

Al recommended not setting the search buffer to skip the first '*' unless we know we are not using MATCH_GLOB. This implements his suggested logic.

Link: http://lkml.kernel.org/r/20180127170748.GF13338@ZenIV.linux.org.uk

Cc: stable@vger.kernel.org Cc: Masami Hiramatsu mhiramat@kernel.org Fixes: 60f1d5e3bac44 ("ftrace: Support full glob matching") Reported-by: Al Viro viro@ZenIV.linux.org.uk Suggsted-by: Al Viro viro@ZenIV.linux.org.uk Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org

This looks good to me.

Reviewed-by: Masami Hiramatsu mhiramat@kernel.org

Thank you!

---

kernel/trace/trace_events_filter.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 61e7f0678d33..a764aec3c9a1 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -400,7 +400,6 @@ enum regex_type filter_parse_regex(char *buff, int len, char **search, int *not) for (i = 0; i < len; i++) { if (buff[i] == '*') { if (!i) {

• 		*search = buff + 1;
  	type = MATCH_END_ONLY;
  } else if (i == len - 1) {
  	if (type == MATCH_END_ONLY)
  

@@ -410,14 +409,14 @@ enum regex_type filter_parse_regex(char *buff, int len, char **search, int *not) buff[i] = 0; break; } else { /* pattern continues, use full glob */

• 		type = MATCH_GLOB;
  

• 		break;
  

• 		return MATCH_GLOB;
  }
  

  } else if (strchr("[?\", buff[i])) {

• 	type = MATCH_GLOB;
  

• 	break;
  

• 	return MATCH_GLOB;
  

  } }
• if (buff[0] == '*')

• *search = buff + 1;
  

return type; } -- 2.15.1