[PATCH 5.4 385/389] 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 |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -300,7 +300,7 @@ static int parse_probe_vars(char *arg, c
 			}
 		} else
 			goto inval_var;
-	} else if (strcmp(arg, "comm") == 0) {
+	} else if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
 		code->op = FETCH_OP_COMM;
 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
 	} else if (((flags & TPARG_FL_MASK) ==
@@ -595,7 +595,8 @@ static int traceprobe_parse_probe_arg_bo
 	 * Since $comm and immediate string can not be dereferred,
 	 * we can find those by strcmp.
 	 */
-	if (strcmp(arg, "$comm") == 0 || strncmp(arg, "\\\"", 2) == 0) {
+	if (strcmp(arg, "$comm") == 0 || strcmp(arg, "$COMM") == 0 ||
+	    strncmp(arg, "\\\"", 2) == 0) {
 		/* The type of $comm must be "string", and not an array. */
 		if (parg->count || (t && strcmp(t, "string")))
 			return -EINVAL;