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ftrace: Remove incorrect setting of glob search field
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commit 7b65865 upstream.

__unregister_ftrace_function_probe() will incorrectly parse the glob filter
because it resets the search variable that was setup by filter_parse_regex().

Al Viro reported this:

    After that call of filter_parse_regex() we could have func_g.search not
    equal to glob only if glob started with '!' or '*'.  In the former case
    we would've buggered off with -EINVAL (not = 1).  In the latter we
    would've set func_g.search equal to glob + 1, calculated the length of
    that thing in func_g.len and proceeded to reset func_g.search back to
    glob.

    Suppose the glob is e.g. *foo*.  We end up with
	    func_g.type = MATCH_MIDDLE_ONLY;
	    func_g.len = 3;
	    func_g.search = "*foo";
    Feeding that to ftrace_match_record() will not do anything sane - we
    will be looking for names containing "*foo" (->len is ignored for that
    one).

Link: http://lkml.kernel.org/r/20180127031706.GE13338@ZenIV.linux.org.uk

Fixes: 3ba0092 ("ftrace: Introduce ftrace_glob structure")
Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Steven Rostedt (VMware) authored and Greg Kroah-Hartman committed Feb 17, 2018
1 parent df11348 commit 2de1085
Showing 1 changed file with 0 additions and 1 deletion.
1 change: 0 additions & 1 deletion kernel/trace/ftrace.c
Original file line number Diff line number Diff line change
@@ -3911,7 +3911,6 @@ __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
func_g.type = filter_parse_regex(glob, strlen(glob),
&func_g.search, &not);
func_g.len = strlen(func_g.search);
func_g.search = glob;

/* we do not support '!' for function probes */
if (WARN_ON(not))

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