From 3b1679e086bb869ca02722f6bd29b3573a6a0e7e Mon Sep 17 00:00:00 2001 From: Andrei-Alexandru Tachici Date: Mon, 2 Mar 2026 11:27:34 +0100 Subject: 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 Cc: Mathieu Desnoyers Link: https://patch.msgid.link/20260302-trace-events-allow-multiple-modules-v1-1-ce4436e37fb8@oss.qualcomm.com Signed-off-by: Andrei-Alexandru Tachici Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace_events.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) 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"); -- cgit v1.2.3