Based on the ftrace documentation, the tp_printk boot parameter
documentation, and the implementation in kernel/trace/trace.c.
Signed-off-by: Stephen Kitt <[email protected]>
---
Changes since v2:
- spelling and grammar fixes in ftrace_dump_on_oops ("outputing it"
-> "outputting them")
- "and::" in a single line in tracepoint_printk
Documentation/admin-guide/sysctl/kernel.rst | 48 +++++++++++++++++++++
1 file changed, 48 insertions(+)
diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst
index 82bfd5892663..b1ad4c86274d 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 outputting them 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 +1212,33 @@ 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::
+
+ 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
=================
--
2.20.1
On Wed, 29 Apr 2020 22:57:56 +0200
Stephen Kitt <[email protected]> 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 <[email protected]>
> ---
> Changes since v2:
> - spelling and grammar fixes in ftrace_dump_on_oops ("outputing it"
> -> "outputting them")
> - "and::" in a single line in tracepoint_printk
I didn't re-read or compare this patch with v1, but if the only changes
were the above:
Acked-by: Steven Rostedt (VMware) <[email protected]>
-- Steve
>
> Documentation/admin-guide/sysctl/kernel.rst | 48 +++++++++++++++++++++
> 1 file changed, 48 insertions(+)
>
> diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst
> index 82bfd5892663..b1ad4c86274d 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 outputting them 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 +1212,33 @@ 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::
> +
> + 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
> =================
>
On Wed, 29 Apr 2020 20:58:01 -0400
Steven Rostedt <[email protected]> wrote:
> On Wed, 29 Apr 2020 22:57:56 +0200
> Stephen Kitt <[email protected]> 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 <[email protected]>
> > ---
> > Changes since v2:
> > - spelling and grammar fixes in ftrace_dump_on_oops ("outputing it"
> > -> "outputting them")
> > - "and::" in a single line in tracepoint_printk
>
> I didn't re-read or compare this patch with v1, but if the only changes
> were the above:
>
> Acked-by: Steven Rostedt (VMware) <[email protected]>
Both applied, thanks.
jon