[PATCH 4.19 285/287] tracing/probes: Have kprobes and uprobes use $COMM too

[Greg Kroah-Hartman]

From: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>

commit ab8384442ee512fc0fc72deeb036110843d0e7ff upstream.

Both $comm and $COMM can be used to get current->comm in eprobes and the
filtering and histogram logic. Make kprobes and uprobes consistent in this
regard and allow both $comm and $COMM as well. Currently kprobes and
uprobes only handle $comm, which is inconsistent with the other utilities,
and can be confusing to users.

Link: https://lkml.kernel.org/r/20220820134401.317014913@xxxxxxxxxxx
Link: https://lore.kernel.org/all/20220820220442.776e1ddaf8836e82edb34d01@xxxxxxxxxx/

Cc: stable@xxxxxxxxxxxxxxx
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Tzvetomir Stoyanov <tz.stoyanov@xxxxxxxxx>
Cc: Tom Zanussi <zanussi@xxxxxxxxxx>
Fixes: 533059281ee5 ("tracing: probeevent: Introduce new argument fetching code")
Suggested-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
Acked-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 kernel/trace/trace_probe.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -361,7 +361,7 @@ static int parse_probe_vars(char *arg, c
 			}
 		} else
 			ret = -EINVAL;
-	} else if (strcmp(arg, "comm") == 0) {
+	} else if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
 		if (strcmp(t->name, "string") != 0 &&
 		    strcmp(t->name, "string_size") != 0)
 			return -EINVAL;
@@ -544,7 +544,7 @@ int traceprobe_parse_probe_arg(char *arg
 	 * The default type of $comm should be "string", and it can't be
 	 * dereferenced.
 	 */
-	if (!t && strcmp(arg, "$comm") == 0)
+	if (!t && (strcmp(arg, "$comm") == 0 || strcmp(arg, "$COMM") == 0))
 		t = "string";
 	parg->type = find_fetch_type(t, ftbl);
 	if (!parg->type) {