From 937fbf111ac17c456cfcbf18412a1417ff3b69ed Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Sat, 8 Feb 2025 10:30:17 -0500 Subject: [PATCH] tracing: Add traceoff_after_boot option Sometimes tracing is used to debug issues during the boot process. Since the trace buffer has a limited amount of storage, it may be prudent to disable tracing after the boot is finished, otherwise the critical information may be overwritten. With this option, the main tracing buffer will be turned off at the end of the boot process. Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Cc: Borislav Petkov Link: https://lore.kernel.org/20250208103017.48a7ec83@batman.local.home Signed-off-by: Steven Rostedt (Google) --- Documentation/admin-guide/kernel-parameters.txt | 9 +++++++++ kernel/trace/trace.c | 11 +++++++++++ 2 files changed, 20 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index fb8752b42ec85..e8ca4eabd1526 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -7279,6 +7279,15 @@ See also "Event triggers" in Documentation/trace/events.rst + traceoff_after_boot + [FTRACE] Sometimes tracing is used to debug issues + during the boot process. Since the trace buffer has a + limited amount of storage, it may be prudent to + disable tracing after the boot is finished, otherwise + the critical information may be overwritten. With this + option, the main tracing buffer will be turned off at + the end of the boot process. + traceoff_on_warning [FTRACE] enable this option to disable tracing when a warning is hit. This turns off "tracing_on". Tracing can diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 0e6d517e74e0f..61458d8c3a61a 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -87,6 +87,7 @@ void __init disable_tracing_selftest(const char *reason) static struct trace_iterator *tracepoint_print_iter; int tracepoint_printk; static bool tracepoint_printk_stop_on_boot __initdata; +static bool traceoff_after_boot __initdata; static DEFINE_STATIC_KEY_FALSE(tracepoint_printk_key); /* For tracers that don't implement custom flags */ @@ -330,6 +331,13 @@ static int __init set_tracepoint_printk_stop(char *str) } __setup("tp_printk_stop_on_boot", set_tracepoint_printk_stop); +static int __init set_traceoff_after_boot(char *str) +{ + traceoff_after_boot = true; + return 1; +} +__setup("traceoff_after_boot", set_traceoff_after_boot); + unsigned long long ns2usecs(u64 nsec) { nsec += 500; @@ -10704,6 +10712,9 @@ __init static int late_trace_init(void) tracepoint_printk = 0; } + if (traceoff_after_boot) + tracing_off(); + tracing_set_default_clock(); clear_boot_tracer(); return 0; -- 2.39.5