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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Tzvetomir Stoyanov <tz.stoyanov@gmail.com>,
        Tom Zanussi <zanussi@kernel.org>,
        "Masami Hiramatsu (Google)" <mhiramat@kernel.org>,
        "Steven Rostedt (Google)" <rostedt@goodmis.org>
Subject: [PATCH 5.15 023/244] tracing/probes: Have kprobes and uprobes use $COMM too
Date:   Tue, 23 Aug 2022 10:23:02 +0200
Message-Id: <20220823080059.836940240@linuxfoundation.org>
In-Reply-To: <20220823080059.091088642@linuxfoundation.org>
References: <20220823080059.091088642@linuxfoundation.org>
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From: Steven Rostedt (Google) <rostedt@goodmis.org>

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@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: 533059281ee5 ("tracing: probeevent: Introduce new argument fetching code")
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 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
@@ -310,7 +310,7 @@ 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) ==
@@ -621,7 +621,8 @@ static int traceprobe_parse_probe_arg_bo
 	 * we can find those by strcmp. But ignore for eprobes.
 	 */
 	if (!(flags & TPARG_FL_TPOINT) &&
-	    (strcmp(arg, "$comm") == 0 || strncmp(arg, "\\\"", 2) == 0)) {
+	    (strcmp(arg, "$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")))
 			goto out;