3.16.72-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Rikard Falkeborn rikard.falkeborn@gmail.com
commit f32c2877bcb068a718bb70094cd59ccc29d4d082 upstream.
There was a missing comparison with 0 when checking if type is "s64" or "u64". Therefore, the body of the if-statement was entered if "type" was "u64" or not "s64", which made the first strcmp() redundant since if type is "u64", it's not "s64".
If type is "s64", the body of the if-statement is not entered but since the remainder of the function consists of if-statements which will not be entered if type is "s64", we will just return "val", which is correct, albeit at the cost of a few more calls to strcmp(), i.e., it will behave just as if the if-statement was entered.
If type is neither "s64" or "u64", the body of the if-statement will be entered incorrectly and "val" returned. This means that any type that is checked after "s64" and "u64" is handled the same way as "s64" and "u64", i.e., the limiting of "val" to fit in for example "s8" is never reached.
This was introduced in the kernel tree when the sources were copied from trace-cmd in commit f7d82350e597 ("tools/events: Add files to create libtraceevent.a"), and in the trace-cmd repo in 1cdbae6035cei ("Implement typecasting in parser") when the function was introduced, i.e., it has always behaved the wrong way.
Detected by cppcheck.
Signed-off-by: Rikard Falkeborn rikard.falkeborn@gmail.com Reviewed-by: Steven Rostedt (VMware) rostedt@goodmis.org Cc: Tzvetomir Stoyanov tstoyanov@vmware.com Fixes: f7d82350e597 ("tools/events: Add files to create libtraceevent.a") Link: http://lkml.kernel.org/r/20190409091529.2686-1-rikard.falkeborn@gmail.com Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Ben Hutchings ben@decadent.org.uk --- tools/lib/traceevent/event-parse.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/tools/lib/traceevent/event-parse.c +++ b/tools/lib/traceevent/event-parse.c @@ -2065,7 +2065,7 @@ eval_type_str(unsigned long long val, co return val & 0xffffffff;
if (strcmp(type, "u64") == 0 || - strcmp(type, "s64")) + strcmp(type, "s64") == 0) return val;
if (strcmp(type, "s8") == 0)