From f38601368f4a0c2a9f859511768dc3957e2e1769 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Thu, 17 Jun 2021 10:51:02 -0400 Subject: tracing: Add tp_printk_stop_on_boot option Add a kernel command line option that disables printing of events to console at late_initcall_sync(). This is useful when needing to see specific events written to console on boot up, but not wanting it when user space starts, as user space may make the console so noisy that the system becomes inoperable. Signed-off-by: Steven Rostedt (VMware) --- Documentation/admin-guide/kernel-parameters.txt | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'Documentation/admin-guide') diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index cb89dbdedc46..0fcc725105cd 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -5605,12 +5605,25 @@ Note, echoing 1 into this file without the tracepoint_printk kernel cmdline option has no effect. + The tp_printk_stop_on_boot (see below) can also be used + to stop the printing of events to console at + late_initcall_sync. + ** CAUTION ** Having tracepoints sent to printk() and activating high frequency tracepoints such as irq or sched, can cause the system to live lock. + tp_printk_stop_on_boot[FTRACE] + When tp_printk (above) is set, it can cause a lot of noise + on the console. It may be useful to only include the + printing of events during boot up, as user space may + make the system inoperable. + + This command line option will stop the printing of events + to console at the late_initcall_sync() time frame. + traceoff_on_warning [FTRACE] enable this option to disable tracing when a warning is hit. This turns off "tracing_on". Tracing can -- cgit v1.2.3