Commit 3b1679e086bb for kernel

commit 3b1679e086bb869ca02722f6bd29b3573a6a0e7e
Author: Andrei-Alexandru Tachici <andrei-alexandru.tachici@oss.qualcomm.com>
Date:   Mon Mar 2 11:27:34 2026 +0100

    tracing: Fix enabling multiple events on the kernel command line and bootconfig

    Multiple events can be enabled on the kernel command line via a comma
    separator. But if the are specified one at a time, then only the last
    event is enabled. This is because the event names are saved in a temporary
    buffer, and each call by the init cmdline code will reset that buffer.

    This also affects names in the boot config file, as it may call the
    callback multiple times with an example of:

      kernel.trace_event = ":mod:rproc_qcom_common", ":mod:qrtr", ":mod:qcom_aoss"

    Change the cmdline callback function to append a comma and the next value
    if the temporary buffer already has content.

    Cc: stable@vger.kernel.org
    Cc: Masami Hiramatsu <mhiramat@kernel.org>
    Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
    Link: https://patch.msgid.link/20260302-trace-events-allow-multiple-modules-v1-1-ce4436e37fb8@oss.qualcomm.com
    Signed-off-by: Andrei-Alexandru Tachici <andrei-alexandru.tachici@oss.qualcomm.com>
    Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index b7343fdfd7b0..249d1cba72c0 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -4493,7 +4493,11 @@ static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;

 static __init int setup_trace_event(char *str)
 {
-	strscpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
+	if (bootup_event_buf[0] != '\0')
+		strlcat(bootup_event_buf, ",", COMMAND_LINE_SIZE);
+
+	strlcat(bootup_event_buf, str, COMMAND_LINE_SIZE);
+
 	trace_set_ring_buffer_expanded(NULL);
 	disable_tracing_selftest("running event tracing");