[for-linus][PATCH 09/10] tracing/probes: Have kprobes and uprobes use $COMM too

From: Steven Rostedt
Date: Sat Aug 20 2022 - 20:08:51 EST


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

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://lore.kernel.org/all/20220820220442.776e1ddaf8836e82edb34d01@xxxxxxxxxx/

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 533059281ee5 ("tracing: probeevent: Introduce new argument fetching code")
Suggested-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
---
kernel/trace/trace_probe.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 4daabbb8b772..36dff277de46 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -314,7 +314,7 @@ 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) ==
@@ -625,7 +625,8 @@ static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size,
* 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;
--
2.35.1