ftrace: Remove incorrect setting of glob search field

Web:        https://git.kernel.org/torvalds/c/7b6586562708d2b3a04fe49f217ddbadbbbb0546
Commit:     7b6586562708d2b3a04fe49f217ddbadbbbb0546
Parent:     841a915d20c7b22fc4f36f12368daf94d9f8cb10
Refname:    refs/heads/master
Author:     Steven Rostedt (VMware) <[email protected]>
AuthorDate: Mon Feb 5 22:05:31 2018 -0500
Committer:  Steven Rostedt (VMware) <[email protected]>
CommitDate: Thu Feb 8 10:11:11 2018 -0500

    ftrace: Remove incorrect setting of glob search field
    
    __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/[email protected]
    
    Cc: [email protected]
    Fixes: 3ba009297149f ("ftrace: Introduce ftrace_glob structure")
    Reviewed-by: Dmitry Safonov <[email protected]>
    Reviewed-by: Masami Hiramatsu <[email protected]>
    Reported-by: Al Viro <[email protected]>
    Signed-off-by: Steven Rostedt (VMware) <[email protected]>
---
 kernel/trace/ftrace.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index dabd9d167d42..eac9ce2c57a2 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -4456,7 +4456,6 @@ unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
 		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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