docs: panic: correct some sys_ifo names in sysctl doc

Patch series "Enable hung_task and lockup cases to dump system info on
demand", v2.

When working on kernel stability issues: panic, task-hung and soft/hard
lockup are frequently met.  And to debug them, user may need lots of
system information at that time, like task call stacks, lock info, memory
info, ftrace dump, etc.

panic case already uses sys_info() for this purpose, and has a
'panic_sys_info' sysctl(also support cmdline setup) interface to take
human readable string like "tasks,mem,timers,locks,ftrace,..." to control
what kinds of information is needed.  Which is also helpful to debug
task-hung and lockup cases.

So this patchset introduces the similar sys_info sysctl interface for
task-hung and lockup cases.

his is mainly for debugging and the info dumping could be intrusive, like
dumping call stack for all tasks when system has huge number of tasks,
similarly for ftrace dump (we may add tracing_stop() and tracing_start()
around it)

Locally these have been used in our bug chasing for stability issues and
were helpful.

As Andrew suggested, add a configurable global 'kernel_sys_info' knob.
When error scenarios like panic/hung-task/lockup etc doesn't setup their
own sys_info knob and calls sys_info() with parameter "0", this global
knob will take effect.  It could be used for other kernel cases like OOM,
which may not need one dedicated sys_info knob.

This patch (of 4):

Some sys_info names wered forgotten to change in patch iterations, while
the right names are defined in kernel/sys_info.c.

Link: https://lkml.kernel.org/r/20251113111039.22701-1-feng.tang@linux.alibaba.com
Link: https://lkml.kernel.org/r/20251113111039.22701-2-feng.tang@linux.alibaba.com
Fixes: d747755917bf ("panic: add 'panic_sys_info' sysctl to take human readable string parameter")
Signed-off-by: Feng Tang <feng.tang@linux.alibaba.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst
index 0065a55bc09ed9967e476ba5162ac1f393731454..a397eeccaea7314581f9d2090b1567060952090b 100644 (file)
--- a/Documentation/admin-guide/sysctl/kernel.rst
+++ b/Documentation/admin-guide/sysctl/kernel.rst
@@ -911,8 +911,8 @@ to 'panic_print'. Possible values are:
 =============   ===================================================
 tasks           print all tasks info
 mem             print system memory info
-timer           print timers info
-lock            print locks info if CONFIG_LOCKDEP is on
+timers          print timers info
+locks           print locks info if CONFIG_LOCKDEP is on
 ftrace          print ftrace buffer
 all_bt          print all CPUs backtrace (if available in the arch)
 blocked_tasks   print only tasks in uninterruptible (blocked) state