tracing/probes: Have kprobes and uprobes use $COMM too

stable inclusion
from stable-v5.10.138
commit 184e73f12cbad9ccad80a390c7731e8c09598225
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I60QFD

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=184e73f12cbad9ccad80a390c7731e8c09598225

--------------------------------

commit ab838444 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@goodmis.org
Link: https://lore.kernel.org/all/20220820220442.776e1ddaf8836e82edb34d01@kernel.org/

Cc: stable@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Fixes: 53305928 ("tracing: probeevent: Introduce new argument fetching code")
Suggested-by: NMasami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: NMasami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: NSteven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Reviewed-by: NWei Li <liwei391@huawei.com>

kernel/trace/trace_probe.c

@@ -300,7 +300,7 @@ static int parse_probe_vars(char *arg, const struct fetch_type *t,
 			}
 		} 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_body(char *arg, ssize_t *size,
 	 * 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;