Commit Graph

37 Commits

Author SHA1 Message Date
Linus Torvalds
c80e42a496 A handful of late-arriving documentation fixes.
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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.
2020-10-23 17:13:53 -07:00
Kees Cook
ac8bf0de6a docs: lkdtm: Modernize and improve details
The details on using LKDTM were overly obscure. Modernize the details
and expand examples to better illustrate how to use the interfaces.
Additionally add missing SPDX header.

Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201015224559.2137489-1-keescook@chromium.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-10-21 15:10:30 -06:00
Albert van der Linde
2c739ced58 lib, include/linux: add usercopy failure capability
Patch series "add fault injection to user memory access", v3.

The goal of this series is to improve testing of fault-tolerance in usages
of user memory access functions, by adding support for fault injection.

syzkaller/syzbot are using the existing fault injection modes and will use
this particular feature also.

The first patch adds failure injection capability for usercopy functions.
The second changes usercopy functions to use this new failure capability
(copy_from_user, ...).  The third patch adds get/put/clear_user failures
to x86.

This patch (of 3):

Add a failure injection capability to improve testing of fault-tolerance
in usages of user memory access functions.

Add CONFIG_FAULT_INJECTION_USERCOPY to enable faults in usercopy
functions.  The should_fail_usercopy function is to be called by these
functions (copy_from_user, get_user, ...) in order to fail or not.

Signed-off-by: Albert van der Linde <alinde@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Akinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Christoph Hellwig <hch@lst.de>
Link: http://lkml.kernel.org/r/20200831171733.955393-1-alinde@google.com
Link: http://lkml.kernel.org/r/20200831171733.955393-2-alinde@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-16 11:11:22 -07:00
Christoph Hellwig
2eb81a3364 nvme: rename and document nvme_end_request
nvme_end_request is a bit misnamed, as it wraps around the
blk_mq_complete_* API.  It's semantics also are non-trivial, so give it
a more descriptive name and add a comment explaining the semantics.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-08-21 17:14:28 -06:00
Christoph Hellwig
ed00aabd5e block: rename generic_make_request to submit_bio_noacct
generic_make_request has always been very confusingly misnamed, so rename
it to submit_bio_noacct to make it clear that it is submit_bio minus
accounting and a few checks.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-01 07:27:24 -06:00
Mauro Carvalho Chehab
113094f743 docs: add some directories to the main documentation index
The contents of those directories were orphaned at the documentation
body.

While those directories could likely be moved to be inside some guide,
I'm opting to just adding their indexes to the main one, removing the
:orphan: and adding the SPDX header.

For the drivers, the rationale is that the documentation contains
a mix of Kernelspace, uAPI and admin-guide. So, better to keep them on
separate directories, as we've be doing with similar subsystem-specific
docs that were not split yet.

For the others, well... I'm too lazy to do the move. Also, it
seems to make sense to keep at least some of those at the main
dir (like kbuild, for example). In any case, a latter patch
could do the move.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
2019-07-15 11:03:03 -03:00
Linus Torvalds
e9a83bd232 It's been a relatively busy cycle for docs:
- A fair pile of RST conversions, many from Mauro.  These create more
    than the usual number of simple but annoying merge conflicts with other
    trees, unfortunately.  He has a lot more of these waiting on the wings
    that, I think, will go to you directly later on.
 
  - A new document on how to use merges and rebases in kernel repos, and one
    on Spectre vulnerabilities.
 
  - Various improvements to the build system, including automatic markup of
    function() references because some people, for reasons I will never
    understand, were of the opinion that :c:func:``function()`` is
    unattractive and not fun to type.
 
  - We now recommend using sphinx 1.7, but still support back to 1.4.
 
  - Lots of smaller improvements, warning fixes, typo fixes, etc.
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Merge tag 'docs-5.3' of git://git.lwn.net/linux

Pull Documentation updates from Jonathan Corbet:
 "It's been a relatively busy cycle for docs:

   - A fair pile of RST conversions, many from Mauro. These create more
     than the usual number of simple but annoying merge conflicts with
     other trees, unfortunately. He has a lot more of these waiting on
     the wings that, I think, will go to you directly later on.

   - A new document on how to use merges and rebases in kernel repos,
     and one on Spectre vulnerabilities.

   - Various improvements to the build system, including automatic
     markup of function() references because some people, for reasons I
     will never understand, were of the opinion that
     :c:func:``function()`` is unattractive and not fun to type.

   - We now recommend using sphinx 1.7, but still support back to 1.4.

   - Lots of smaller improvements, warning fixes, typo fixes, etc"

* tag 'docs-5.3' of git://git.lwn.net/linux: (129 commits)
  docs: automarkup.py: ignore exceptions when seeking for xrefs
  docs: Move binderfs to admin-guide
  Disable Sphinx SmartyPants in HTML output
  doc: RCU callback locks need only _bh, not necessarily _irq
  docs: format kernel-parameters -- as code
  Doc : doc-guide : Fix a typo
  platform: x86: get rid of a non-existent document
  Add the RCU docs to the core-api manual
  Documentation: RCU: Add TOC tree hooks
  Documentation: RCU: Rename txt files to rst
  Documentation: RCU: Convert RCU UP systems to reST
  Documentation: RCU: Convert RCU linked list to reST
  Documentation: RCU: Convert RCU basic concepts to reST
  docs: filesystems: Remove uneeded .rst extension on toctables
  scripts/sphinx-pre-install: fix out-of-tree build
  docs: zh_CN: submitting-drivers.rst: Remove a duplicated Documentation/
  Documentation: PGP: update for newer HW devices
  Documentation: Add section about CPU vulnerabilities for Spectre
  Documentation: platform: Delete x86-laptop-drivers.txt
  docs: Note that :c:func: should no longer be used
  ...
2019-07-09 12:34:26 -07:00
Akinobu Mita
7e31d8215f Documentation: nvme: add an example for nvme fault injection
This adds an example of how to inject errors into admin commands.

Suggested-by: Thomas Tai <thomas.tai@oracle.com>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Minwoo Im <minwoo.im@samsung.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
2019-06-21 11:15:50 +02:00
Mauro Carvalho Chehab
10ffebbed5 docs: fault-injection: convert docs to ReST and rename to *.rst
The conversion is actually:
  - add blank lines and identation in order to identify paragraphs;
  - fix tables markups;
  - add some lists markups;
  - mark literal blocks;
  - adjust title markups.

At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Federico Vaga <federico.vaga@vaga.pv.it>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2019-06-14 14:21:07 -06:00
Laurent Gauthier
2d87948a19 doc: fault-injection: fix macro name in example
Signed-off-by: Laurent Gauthier <laurent.gauthier@soccasys.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2019-01-07 15:36:11 -07:00
Thomas Tai
cf4182f3d0 Documentation: nvme: Documentation for nvme fault injection
Add examples to show how to use nvme fault injection.

Signed-off-by: Thomas Tai <thomas.tai@oracle.com>
Reviewed-by: Eric Saint-Etienne <eric.saint.etienne@oracle.com>
Signed-off-by: Karl Volz <karl.volz@oracle.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-26 08:53:43 -06:00
Linus Torvalds
255442c938 Documentation updates for 4.16. New stuff includes refcount_t
documentation, errseq documentation, kernel-doc support for nested
 structure definitions, the removal of lots of crufty kernel-doc support for
 unused formats, SPDX tag documentation, the beginnings of a manual for
 subsystem maintainers, and lots of fixes and updates.
 
 As usual, some of the changesets reach outside of Documentation/ to effect
 kerneldoc comment fixes.  It also adds the new LICENSES directory, of which
 Thomas promises I do not need to be the maintainer.
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Merge tag 'docs-4.16' of git://git.lwn.net/linux

Pull documentation updates from Jonathan Corbet:
 "Documentation updates for 4.16.

  New stuff includes refcount_t documentation, errseq documentation,
  kernel-doc support for nested structure definitions, the removal of
  lots of crufty kernel-doc support for unused formats, SPDX tag
  documentation, the beginnings of a manual for subsystem maintainers,
  and lots of fixes and updates.

  As usual, some of the changesets reach outside of Documentation/ to
  effect kerneldoc comment fixes. It also adds the new LICENSES
  directory, of which Thomas promises I do not need to be the
  maintainer"

* tag 'docs-4.16' of git://git.lwn.net/linux: (65 commits)
  linux-next: docs-rst: Fix typos in kfigure.py
  linux-next: DOC: HWPOISON: Fix path to debugfs in hwpoison.txt
  Documentation: Fix misconversion of #if
  docs: add index entry for networking/msg_zerocopy
  Documentation: security/credentials.rst: explain need to sort group_list
  LICENSES: Add MPL-1.1 license
  LICENSES: Add the GPL 1.0 license
  LICENSES: Add Linux syscall note exception
  LICENSES: Add the MIT license
  LICENSES: Add the BSD-3-clause "Clear" license
  LICENSES: Add the BSD 3-clause "New" or "Revised" License
  LICENSES: Add the BSD 2-clause "Simplified" license
  LICENSES: Add the LGPL-2.1 license
  LICENSES: Add the LGPL 2.0 license
  LICENSES: Add the GPL 2.0 license
  Documentation: Add license-rules.rst to describe how to properly identify file licenses
  scripts: kernel_doc: better handle show warnings logic
  fs/*/Kconfig: drop links to 404-compliant http://acl.bestbits.at
  doc: md: Fix a file name to md-fault.c in fault-injection.txt
  errseq: Add to documentation tree
  ...
2018-01-31 19:25:25 -08:00
Masami Hiramatsu
4b1a29a7f5 error-injection: Support fault injection framework
Support in-kernel fault-injection framework via debugfs.
This allows you to inject a conditional error to specified
function using debugfs interfaces.

Here is the result of test script described in
Documentation/fault-injection/fault-injection.txt

  ===========
  # ./test_fail_function.sh
  1+0 records in
  1+0 records out
  1048576 bytes (1.0 MB, 1.0 MiB) copied, 0.0227404 s, 46.1 MB/s
  btrfs-progs v4.4
  See http://btrfs.wiki.kernel.org for more information.

  Label:              (null)
  UUID:               bfa96010-12e9-4360-aed0-42eec7af5798
  Node size:          16384
  Sector size:        4096
  Filesystem size:    1001.00MiB
  Block group profiles:
    Data:             single            8.00MiB
    Metadata:         DUP              58.00MiB
    System:           DUP              12.00MiB
  SSD detected:       no
  Incompat features:  extref, skinny-metadata
  Number of devices:  1
  Devices:
     ID        SIZE  PATH
      1  1001.00MiB  /dev/loop2

  mount: mount /dev/loop2 on /opt/tmpmnt failed: Cannot allocate memory
  SUCCESS!
  ===========

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-01-12 17:33:38 -08:00
Masanari Iida
1892ce4cdd doc: md: Fix a file name to md-fault.c in fault-injection.txt
drivers/md/faulty.c has been renamed to md-faulty.c after
following commit merged int to the main line.

  935fe0983e .

But the file name in fault-injection.txt has not been changed.
Now the actual file name and document are in sync.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2018-01-01 12:43:09 -07:00
Thomas Gleixner
f4c09f87ad cpu/hotplug: Get rid of CPU hotplug notifier leftovers
The CPU hotplug notifiers are history. Remove the last reminders.

Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-11-13 10:03:53 +01:00
Akinobu Mita
168c42bc56 fault-inject: add /proc/<pid>/fail-nth
fail-nth interface is only created in /proc/self/task/<current-tid>/.
This change also adds it in /proc/<pid>/.

This makes shell based tool a bit simpler.

	$ bash -c "builtin echo 100 > /proc/self/fail-nth && exec ls /"

Link: http://lkml.kernel.org/r/1491490561-10485-6-git-send-email-akinobu.mita@gmail.com
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-14 15:05:13 -07:00
Akinobu Mita
bfc740938d fault-inject: make fail-nth read/write interface symmetric
The read interface for fail-nth looks a bit odd.  Read from this file
returns "NYYYY..." or "YYYYY..." (this makes me surprise when cat this
file).  Because there is no EOF condition.  The first character
indicates current->fail_nth is zero or not, and then current->fail_nth
is reset to zero.

Just returning task->fail_nth value is more natural to understand.

Link: http://lkml.kernel.org/r/1491490561-10485-4-git-send-email-akinobu.mita@gmail.com
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-14 15:05:13 -07:00
Akinobu Mita
9049f2f6e7 fault-inject: parse as natural 1-based value for fail-nth write interface
The value written to fail-nth file is parsed as 0-based.  Parsing as
one-based is more natural to understand and it enables to cancel the
previous setup by simply writing '0'.

This change also converts task->fail_nth from signed to unsigned int.

Link: http://lkml.kernel.org/r/1491490561-10485-3-git-send-email-akinobu.mita@gmail.com
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-14 15:05:13 -07:00
Dmitry Vyukov
e41d58185f fault-inject: support systematic fault injection
Add /proc/self/task/<current-tid>/fail-nth file that allows failing
0-th, 1-st, 2-nd and so on calls systematically.
Excerpt from the added documentation:

 "Write to this file of integer N makes N-th call in the current task
  fail (N is 0-based). Read from this file returns a single char 'Y' or
  'N' that says if the fault setup with a previous write to this file
  was injected or not, and disables the fault if it wasn't yet injected.
  Note that this file enables all types of faults (slab, futex, etc).
  This setting takes precedence over all other generic settings like
  probability, interval, times, etc. But per-capability settings (e.g.
  fail_futex/ignore-private) take precedence over it. This feature is
  intended for systematic testing of faults in a single system call. See
  an example below"

Why add a new setting:
1. Existing settings are global rather than per-task.
   So parallel testing is not possible.
2. attr->interval is close but it depends on attr->count
   which is non reset to 0, so interval does not work as expected.
3. Trying to model this with existing settings requires manipulations
   of all of probability, interval, times, space, task-filter and
   unexposed count and per-task make-it-fail files.
4. Existing settings are per-failure-type, and the set of failure
   types is potentially expanding.
5. make-it-fail can't be changed by unprivileged user and aggressive
   stress testing better be done from an unprivileged user.
   Similarly, this would require opening the debugfs files to the
   unprivileged user, as he would need to reopen at least times file
   (not possible to pre-open before dropping privs).

The proposed interface solves all of the above (see the example).

We want to integrate this into syzkaller fuzzer.  A prototype has found
10 bugs in kernel in first day of usage:

  https://groups.google.com/forum/#!searchin/syzkaller/%22FAULT_INJECTION%22%7Csort:relevance

I've made the current interface work with all types of our sandboxes.
For setuid the secret sauce was prctl(PR_SET_DUMPABLE, 1, 0, 0, 0) to
make /proc entries non-root owned.  So I am fine with the current
version of the code.

[akpm@linux-foundation.org: fix build]
Link: http://lkml.kernel.org/r/20170328130128.101773-1-dvyukov@google.com
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-12 16:26:01 -07:00
Ido Schimmel
c39d0454ec net: Add support for CHANGEUPPER notifier error injection
Since CHANGEUPPER can now fail, add support for it in the newly
introduced netdev notifier error injection infrastructure.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-03 11:49:23 -05:00
Nikolay Aleksandrov
02fff96a79 net: add support for netdev notifier error injection
This module allows to insert errors in some of netdevice's notifier
events. All network drivers use these notifiers to signal various events
and to check if they are allowed, e.g. PRECHANGEMTU and CHANGEMTU
afterwards. Until recently I had to run failure tests by injecting
a custom module, but now this infrastructure makes it trivial to test
these failure paths. Some of the recent bugs I fixed were found using
this module.
Here's an example:
 $ cd /sys/kernel/debug/notifier-error-inject/netdev
 $ echo -22 > actions/NETDEV_CHANGEMTU/error
 $ ip link set eth0 mtu 1024
 RTNETLINK answers: Invalid argument

CC: Akinobu Mita <akinobu.mita@gmail.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: netdev <netdev@vger.kernel.org>
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-01 15:31:57 -05:00
Davidlohr Bueso
ab51fbab39 futex: Fault/error injection capabilities
Although futexes are well known for being a royal pita,
we really have very little debugging capabilities - except
for relying on tglx's eye half the time.

By simply making use of the existing fault-injection machinery,
we can improve this situation, allowing generating artificial
uaddress faults and deadlock scenarios. Of course, when this is
disabled in production systems, the overhead for failure checks
is practically zero -- so this is very cheap at the same time.
Future work would be nice to now enhance trinity to make use of
this.

There is a special tunable 'ignore-private', which can filter
out private futexes. Given the tsk->make_it_fail filter and
this option, pi futexes can be narrowed down pretty closely.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Darren Hart <darren@dvhart.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Link: http://lkml.kernel.org/r/1435645562-975-3-git-send-email-dave@stgolabs.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-07-20 11:45:45 +02:00
Masanari Iida
4e79162a52 doc: fix quite a few typos within Documentation
Correct spelling typo in Documentations

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2012-11-19 14:28:24 +01:00
Akinobu Mita
c24aa64d16 fault-injection: add tool to run command with failslab or fail_page_alloc
This adds tools/testing/fault-injection/failcmd.sh to run a command while
injecting slab/page allocation failures via fault injection.

Example:

Run a command "make -C tools/testing/selftests/ run_tests" with
injecting slab allocation failure.

	# ./tools/testing/fault-injection/failcmd.sh \
		-- make -C tools/testing/selftests/ run_tests

Same as above except to specify 100 times failures at most instead of
one time at most by default.

	# ./tools/testing/fault-injection/failcmd.sh --times=100 \
		-- make -C tools/testing/selftests/ run_tests

Same as above except to inject page allocation failure instead of slab
allocation failure.

	# env FAILCMD_TYPE=fail_page_alloc \
		./tools/testing/fault-injection/failcmd.sh --times=100 \
		-- make -C tools/testing/selftests/ run_tests

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-30 17:25:22 -07:00
Akinobu Mita
8d43828814 fault-injection: notifier error injection
This patchset provides kernel modules that can be used to test the error
handling of notifier call chain failures by injecting artifical errors to
the following notifier chain callbacks.

 * CPU notifier
 * PM notifier
 * memory hotplug notifier
 * powerpc pSeries reconfig notifier

Example: Inject CPU offline error (-1 == -EPERM)

  # cd /sys/kernel/debug/notifier-error-inject/cpu
  # echo -1 > actions/CPU_DOWN_PREPARE/error
  # echo 0 > /sys/devices/system/cpu/cpu1/online
  bash: echo: write error: Operation not permitted

The patchset also adds cpu and memory hotplug tests to
tools/testing/selftests These tests first do simple online and offline
test and then do fault injection tests if notifier error injection
module is available.

This patch:

The notifier error injection provides the ability to inject artifical
errors to specified notifier chain callbacks.  It is useful to test the
error handling of notifier call chain failures.

This adds common basic functions to define which type of events can be
fail and to initialize the debugfs interface to control what error code
should be returned and which event should be failed.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Greg KH <greg@kroah.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-30 17:25:22 -07:00
Per Forlin
199e3f4b41 fault-injection: update documentation with the mmc module param
Signed-off-by: Per Forlin <per.forlin@linaro.org>
Reviewed-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
2011-10-26 16:32:13 -04:00
Per Forlin
1e4cb22bb5 fault-inject: add documentation on MMC IO fault injection
Add description on how to enable random fault injection
for MMC IO.

Signed-off-by: Per Forlin <per.forlin@linaro.org>
Acked-by: Akinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
2011-10-26 15:43:34 -04:00
Akinobu Mita
dd48c085c1 fault-injection: add ability to export fault_attr in arbitrary directory
init_fault_attr_dentries() is used to export fault_attr via debugfs.
But it can only export it in debugfs root directory.

Per Forlin is working on mmc_fail_request which adds support to inject
data errors after a completed host transfer in MMC subsystem.

The fault_attr for mmc_fail_request should be defined per mmc host and
export it in debugfs directory per mmc host like
/sys/kernel/debug/mmc0/mmc_fail_request.

init_fault_attr_dentries() doesn't help for mmc_fail_request.  So this
introduces fault_create_debugfs_attr() which is able to create a
directory in the arbitrary directory and replace
init_fault_attr_dentries().

[akpm@linux-foundation.org: extraneous semicolon, per Randy]
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Tested-by: Per Forlin <per.forlin@linaro.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-08-03 14:25:20 -10:00
Simon Kagstrom
0347af4ee3 lkdtm: add debugfs access and loosen KPROBE ties
Add adds a debugfs interface and additional failure modes to LKDTM to
provide similar functionality to the provoke-crash driver submitted here:

  http://lwn.net/Articles/371208/

Crashes can now be induced either through module parameters (as before)
or through the debugfs interface as in provoke-crash.

The patch also provides a new "direct" interface, where KPROBES are not
used, i.e., the crash is invoked directly upon write to the debugfs
file. When built without KPROBES configured, only this mode is available.

Signed-off-by: Simon Kagstrom <simon.kagstrom@netinsight.net>
Cc: M. Mohan Kumar <mohan@in.ibm.com>
Cc: Americo Wang <xiyou.wangcong@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-06 11:26:32 -08:00
Anton Blanchard
a225a5cc2c fault injection: correct function names in documentation
init_fault_attr_entries() should be init_fault_attr_dentries().

cleanup_fault_attr_entries() should be cleanup_fault_attr_dentries().

Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-02-02 18:11:22 -08:00
GeunSik Lim
156f5a7801 debugfs: Fix terminology inconsistency of dir name to mount debugfs filesystem.
Many developers use "/debug/" or "/debugfs/" or "/sys/kernel/debug/"
directory name to mount debugfs filesystem for ftrace according to
./Documentation/tracers/ftrace.txt file.

And, three directory names(ex:/debug/, /debugfs/, /sys/kernel/debug/) is
existed in kernel source like ftrace, DRM, Wireless, Documentation,
Network[sky2]files to mount debugfs filesystem.

debugfs means debug filesystem for debugging easy to use by greg kroah
hartman. "/sys/kernel/debug/" name is suitable as directory name
of debugfs filesystem.
- debugfs related reference: http://lwn.net/Articles/334546/

Fix inconsistency of directory name to mount debugfs filesystem.

* From Steven Rostedt
  - find_debugfs() and tracing_files() in this patch.

Signed-off-by: GeunSik Lim <geunsik.lim@samsung.com>
Acked-by     : Inaky Perez-Gonzalez <inaky@linux.intel.com>
Reviewed-by  : Steven Rostedt <rostedt@goodmis.org>
Reviewed-by  : James Smart <james.smart@emulex.com>
CC: Jiri Kosina <trivial@kernel.org>
CC: David Airlie <airlied@linux.ie>
CC: Peter Osterlund <petero2@telia.com>
CC: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
CC: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
CC: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-06-15 21:30:28 -07:00
Akinobu Mita
185848707e fault-injection: fix example scripts in documentation
Fix and cleanup example scripts in fault injection documentation.

1. Eliminate broken oops() shell function.

2. Fold failcmd.sh and failmodule.sh into example scripts. It makes
   the example scripts work independent of current working directory.

3. Set "space" parameter to 0 to start injecting errors immediately.

4. Use /sys/module/<modulename>/sections/.data as upper bound of
   .text section. Because some module doesn't have .exit.text section.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 09:05:45 -07:00
Akinobu Mita
54114994f4 fault-injection: add min-order parameter to fail_page_alloc
Limiting smaller allocation failures by fault injection helps to find real
possible bugs.  Because higher order allocations are likely to fail and
zero-order allocations are not likely to fail.

This patch adds min-order parameter to fail_page_alloc.  It specifies the
minimum page allocation order to be injected failures.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 09:05:45 -07:00
Don Mullis
5d0ffa2b84 [PATCH] fault-injection: Correct, disambiguate, and reformat documentation
Correct, disambiguate, and reformat documentation.

Signed-off-by: Don Mullis <dwm@meer.net>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 08:29:03 -08:00
Akinobu Mita
329409aeda [PATCH] fault injection: stacktrace filtering
This patch provides stacktrace filtering feature.

The stacktrace filter allows failing only for the caller you are
interested in.

For example someone may want to inject kmalloc() failures into
only e100 module. they want to inject not only direct kmalloc() call,
but also indirect allocation, too.

- e100_poll --> netif_receive_skb --> packet_rcv_spkt --> skb_clone
  --> kmem_cache_alloc

This patch enables to detect function calls like this by stacktrace
and inject failures. The script Documentaion/fault-injection/failmodule.sh
helps it.

The range of text section of loaded e100 is expected to be
[/sys/module/e100/sections/.text, /sys/module/e100/sections/.exit.text)

So failmodule.sh stores these values into /debug/failslab/address-start
and /debug/failslab/address-end. The maximum stacktrace depth is specified
by /debug/failslab/stacktrace-depth.

Please see the example that demonstrates how to inject slab allocation
failures only for a specific module
in Documentation/fault-injection/fault-injection.txt

[dwm@meer.net: reject failure if any caller lies within specified range]
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Don Mullis <dwm@meer.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 08:29:03 -08:00
Akinobu Mita
8a8b6502fb [PATCH] fault-injection capability for kmalloc
This patch provides fault-injection capability for kmalloc.

Boot option:

failslab=<interval>,<probability>,<space>,<times>

	<interval> -- specifies the interval of failures.

	<probability> -- specifies how often it should fail in percent.

	<space> -- specifies the size of free space where memory can be
		   allocated safely in bytes.

	<times> -- specifies how many times failures may happen at most.

Debugfs:

/debug/failslab/interval
/debug/failslab/probability
/debug/failslab/specifies
/debug/failslab/times
/debug/failslab/ignore-gfp-highmem
/debug/failslab/ignore-gfp-wait

Example:

	failslab=10,100,0,-1

slab allocation (kmalloc(), kmem_cache_alloc(),..) fails once per 10 times.

Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 08:29:02 -08:00
Akinobu Mita
de1ba09b21 [PATCH] fault injection: documentation and scripts
This patch set provides some fault-injection capabilities.

- kmalloc() failures

- alloc_pages() failures

- disk IO errors

We can see what really happens if those failures happen.

In order to enable these fault-injection capabilities:

1. Enable relevant config options (CONFIG_FAILSLAB, CONFIG_PAGE_ALLOC,
   CONFIG_MAKE_REQUEST) and if you want to configure them via debugfs,
   enable CONFIG_FAULT_INJECTION_DEBUG_FS.

2. Build and boot with this kernel

3. Configure fault-injection capabilities behavior by boot option or debugfs

   - Boot option

     failslab=
     fail_page_alloc=
     fail_make_request=

   - Debugfs

     /debug/failslab/*
     /debug/fail_page_alloc/*
     /debug/fail_make_request/*

   Please refer to the Documentation/fault-injection/fault-injection.txt
   for details.

4. See what really happens.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Don Mullis <dwm@meer.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 08:29:02 -08:00