Commit 5c963727 authored Aug 20, 2022 by Steven Rostedt (Google) Committed by Greg Kroah-Hartman Aug 25, 2022

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

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: 53305928 ("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>

parent 5d8244d4

kernel/trace/trace_probe.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -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;