Patch "tracing: fprobe-event: Fix to check tracepoint event and return" has been added to the 6.6-stable tree

[<gregkh@xxxxxxxxxxxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    tracing: fprobe-event: Fix to check tracepoint event and return

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     tracing-fprobe-event-fix-to-check-tracepoint-event-and-return.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.


>From ce51e6153f7781bcde0f8bb4c81d6fd85ee422e6 Mon Sep 17 00:00:00 2001
From: "Masami Hiramatsu (Google)" <mhiramat@xxxxxxxxxx>
Date: Wed, 8 Nov 2023 21:12:39 +0900
Subject: tracing: fprobe-event: Fix to check tracepoint event and return

From: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>

commit ce51e6153f7781bcde0f8bb4c81d6fd85ee422e6 upstream.

Fix to check the tracepoint event is not valid with $retval.
The commit 08c9306fc2e3 ("tracing/fprobe-event: Assume fprobe is
a return event by $retval") introduced automatic return probe
conversion with $retval. But since tracepoint event does not
support return probe, $retval is not acceptable.

Without this fix, ftracetest, tprobe_syntax_errors.tc fails;

[22] Tracepoint probe event parser error log check      [FAIL]
 ----
 # tail 22-tprobe_syntax_errors.tc-log.mRKroL
 + ftrace_errlog_check trace_fprobe t kfree ^$retval dynamic_events
 + printf %s t kfree
 + wc -c
 + pos=8
 + printf %s t kfree ^$retval
 + tr -d ^
 + command=t kfree $retval
 + echo Test command: t kfree $retval
 Test command: t kfree $retval
 + echo
 ----

So 't kfree $retval' should fail (tracepoint doesn't support
return probe) but passed it.

Link: https://lore.kernel.org/all/169944555933.45057.12831706585287704173.stgit@devnote2/

Fixes: 08c9306fc2e3 ("tracing/fprobe-event: Assume fprobe is a return event by $retval")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 kernel/trace/trace_fprobe.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c
index 8bfe23af9c73..7d2ddbcfa377 100644
--- a/kernel/trace/trace_fprobe.c
+++ b/kernel/trace/trace_fprobe.c
@@ -927,11 +927,12 @@ static int parse_symbol_and_return(int argc, const char *argv[],
 	for (i = 2; i < argc; i++) {
 		tmp = strstr(argv[i], "$retval");
 		if (tmp && !isalnum(tmp[7]) && tmp[7] != '_') {
+			if (is_tracepoint) {
+				trace_probe_log_set_index(i);
+				trace_probe_log_err(tmp - argv[i], RETVAL_ON_PROBE);
+				return -EINVAL;
+			}
 			*is_return = true;
-			/*
-			 * NOTE: Don't check is_tracepoint here, because it will
-			 * be checked when the argument is parsed.
-			 */
 			break;
 		}
 	}
-- 
2.43.0



Patches currently in stable-queue which might be from mhiramat@xxxxxxxxxx are

queue-6.6/tracing-fprobe-event-fix-to-check-tracepoint-event-and-return.patch
queue-6.6/tracing-have-the-user-copy-of-synthetic-event-address-use-correct-context.patch