Commit c80e42a4 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'docs-5.10-2' of git://git.lwn.net/linux 

Pull documentation fixes from Jonathan Corbet:
 "A handful of late-arriving documentation fixes"

* tag 'docs-5.10-2' of git://git.lwn.net/linux:
  docs: Add two missing entries in vm sysctl index
  docs/vm: trivial fixes to several spelling mistakes
  docs: submitting-patches: describe preserving review/test tags
  Documentation: Chinese translation of Documentation/arm64/hugetlbpage.rst
  Documentation: x86: fix a missing word in x86_64/mm.rst.
  docs: driver-api: remove a duplicated index entry
  docs: lkdtm: Modernize and improve details
  docs: deprecated.rst: Expand str*cpy() replacement notes
  docs/cpu-load: format the example code.
parents a5e5c274 62af6964

Documentation/admin-guide/cpu-load.rst

+33 −30
Original line number Diff line number Diff line
@@ -66,16 +66,19 @@ will lead to quite erratic information inside ``/proc/stat``:: 
		(void) signr;

		stop = 1;

	}



	static unsigned long hog (unsigned long niters)

	{

		stop = 0;

		while (!stop && --niters);

		return niters;

	}



	int main (void)

	{

		int i;

	struct itimerval it = { .it_interval = { .tv_sec = 0, .tv_usec = 1 },

		struct itimerval it = {

			.it_interval = { .tv_sec = 0, .tv_usec = 1 },

			.it_value    = { .tv_sec = 0, .tv_usec = 1 } };

		sigset_t set;

		unsigned long v[HIST];

Documentation/admin-guide/sysctl/vm.rst

+2 −0
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ Currently, these files are in /proc/sys/vm: 
- admin_reserve_kbytes

- block_dump

- compact_memory

- compaction_proactiveness

- compact_unevictable_allowed

- dirty_background_bytes

- dirty_background_ratio
@@ -37,6 +38,7 @@ Currently, these files are in /proc/sys/vm: 
- dirty_writeback_centisecs

- drop_caches

- extfrag_threshold

- highmem_is_dirtyable

- hugetlb_shm_group

- laptop_mode

- legacy_va_layout

Documentation/arm64/hugetlbpage.rst

+2 −0
Original line number Diff line number Diff line 
.. _hugetlbpage_index:



====================

HugeTLBpage on ARM64

====================

Documentation/driver-api/index.rst

+0 −1
Original line number Diff line number Diff line
@@ -77,7 +77,6 @@ available subsections can be seen below. 
   console

   dcdbas

   eisa

   ipmb

   isa

   isapnp

   io-mapping

Documentation/fault-injection/provoke-crashes.rst

+33 −23
Original line number Diff line number Diff line 
===============

Provoke crashes

===============

.. SPDX-License-Identifier: GPL-2.0



The lkdtm module provides an interface to crash or injure the kernel at

predefined crashpoints to evaluate the reliability of crash dumps obtained

using different dumping solutions. The module uses KPROBEs to instrument

crashing points, but can also crash the kernel directly without KRPOBE

support.

============================================================

Provoking crashes with Linux Kernel Dump Test Module (LKDTM)

============================================================



The lkdtm module provides an interface to disrupt (and usually crash)

the kernel at predefined code locations to evaluate the reliability of

the kernel's exception handling and to test crash dumps obtained using

different dumping solutions. The module uses KPROBEs to instrument the

trigger location, but can also trigger the kernel directly without KPROBE

support via debugfs.



You can provide the way either through module arguments when inserting

the module, or through a debugfs interface.

You can select the location of the trigger ("crash point name") and the

type of action ("crash point type") either through module arguments when

inserting the module, or through the debugfs interface.



Usage::
@@ -18,31 +21,38 @@ Usage:: 
			[cpoint_count={>0}]



recur_count

	Recursion level for the stack overflow test. Default is 10.

	Recursion level for the stack overflow test. By default this is

	dynamically calculated based on kernel configuration, with the

	goal of being just large enough to exhaust the kernel stack. The

	value can be seen at `/sys/module/lkdtm/parameters/recur_count`.



cpoint_name

	Crash point where the kernel is to be crashed. It can be

	Where in the kernel to trigger the action. It can be

	one of INT_HARDWARE_ENTRY, INT_HW_IRQ_EN, INT_TASKLET_ENTRY,

	FS_DEVRW, MEM_SWAPOUT, TIMERADD, SCSI_DISPATCH_CMD,

	IDE_CORE_CP, DIRECT

	IDE_CORE_CP, or DIRECT



cpoint_type

	Indicates the action to be taken on hitting the crash point.

	It can be one of PANIC, BUG, EXCEPTION, LOOP, OVERFLOW,

	CORRUPT_STACK, UNALIGNED_LOAD_STORE_WRITE, OVERWRITE_ALLOCATION,

	WRITE_AFTER_FREE,

	These are numerous, and best queried directly from debugfs. Some

	of the common ones are PANIC, BUG, EXCEPTION, LOOP, and OVERFLOW.

	See the contents of `/sys/kernel/debug/provoke-crash/DIRECT` for

	a complete list.



cpoint_count

	Indicates the number of times the crash point is to be hit

	to trigger an action. The default is 10.

	before triggering the action. The default is 10 (except for

	DIRECT, which always fires immediately).



You can also induce failures by mounting debugfs and writing the type to

<mountpoint>/provoke-crash/<crashpoint>. E.g.::

<debugfs>/provoke-crash/<crashpoint>. E.g.::



  mount -t debugfs debugfs /mnt

  echo EXCEPTION > /mnt/provoke-crash/INT_HARDWARE_ENTRY

  mount -t debugfs debugfs /sys/kernel/debug

  echo EXCEPTION > /sys/kernel/debug/provoke-crash/INT_HARDWARE_ENTRY



The special file `DIRECT` will induce the action directly without KPROBE

instrumentation. This mode is the only one available when the module is

built for a kernel without KPROBEs support::



A special file is `DIRECT` which will induce the crash directly without

KPROBE instrumentation. This mode is the only one available when the module

is built on a kernel without KPROBEs support.
 
  # Instead of having a BUG kill your shell, have it kill "cat":

  cat <(echo WRITE_RO) >/sys/kernel/debug/provoke-crash/DIRECT

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