On Thu, 23 Apr 2020 20:36:50 +0200 Stephen Kitt <steve@xxxxxxx> wrote: > Based on the ftrace documentation, the tp_printk boot parameter > documentation, and the implementation in kernel/trace/trace.c. > > Signed-off-by: Stephen Kitt <steve@xxxxxxx> This one could benefit from an ack from Steve (CC'd). Also one other little nit below: > Documentation/admin-guide/sysctl/kernel.rst | 50 +++++++++++++++++++++ > 1 file changed, 50 insertions(+) > > diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst > index 82bfd5892663..d4bbdaf96ebc 100644 > --- a/Documentation/admin-guide/sysctl/kernel.rst > +++ b/Documentation/admin-guide/sysctl/kernel.rst > @@ -265,6 +265,27 @@ domain names are in general different. For a detailed discussion > see the ``hostname(1)`` man page. > > > +ftrace_dump_on_oops > +=================== > + > +Determines whether ``ftrace_dump()`` should be called on an oops (or > +kernel panic). This will output the contents of the ftrace buffers to > +the console. This is very useful for capturing traces that lead to > +crashes and outputing it to a serial console. > + > += =================================================== > +0 Disabled (default). > +1 Dump buffers of all CPUs. > +2 Dump the buffer of the CPU that triggered the oops. > += =================================================== > + > + > +ftrace_enabled, stack_tracer_enabled > +==================================== > + > +See :doc:`/trace/ftrace`. > + > + > hardlockup_all_cpu_backtrace > ============================ > > @@ -1191,6 +1212,35 @@ If a value outside of this range is written to ``threads-max`` an > ``EINVAL`` error occurs. > > > +traceoff_on_warning > +=================== > + > +When set, disables tracing (see :doc:`/trace/ftrace`) when a > +``WARN()`` is hit. > + > + > +tracepoint_printk > +================= > + > +When tracepoints are sent to printk() (enabled by the ``tp_printk`` > +boot parameter), this entry provides runtime control:: > + > + echo 0 > /proc/sys/kernel/tracepoint_printk > + > +will stop tracepoints from being sent to printk(), and > + > +:: I would just make that ", and::" and avoid the separate line. > + > + echo 1 > /proc/sys/kernel/tracepoint_printk > + > +will send them to printk() again. > + > +This only works if the kernel was booted with ``tp_printk`` enabled. > + > +See :doc:`/admin-guide/kernel-parameters` and > +:doc:`/trace/boottime-trace`. > + > + > unknown_nmi_panic > ================= > Thanks, jon
