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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.
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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 <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jonathan Corbet <[email protected]>
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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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Akinobu Mita <[email protected]>
Reviewed-by: Alexander Potapenko <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Peter Zijlstra (Intel) <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Andrey Konovalov <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Reviewed-by: Sagi Grimberg <[email protected]>
Reviewed-by: Mike Snitzer <[email protected]>
Signed-off-by: Sagi Grimberg <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
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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 <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
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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 <[email protected]>
Acked-by: Bartlomiej Zolnierkiewicz <[email protected]>
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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
...
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This adds an example of how to inject errors into admin commands.
Suggested-by: Thomas Tai <[email protected]>
Signed-off-by: Akinobu Mita <[email protected]>
Reviewed-by: Chaitanya Kulkarni <[email protected]>
Reviewed-by: Minwoo Im <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>
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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 <[email protected]>
Acked-by: Federico Vaga <[email protected]>
Signed-off-by: Jonathan Corbet <[email protected]>
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Signed-off-by: Laurent Gauthier <[email protected]>
Signed-off-by: Jonathan Corbet <[email protected]>
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Add examples to show how to use nvme fault injection.
Signed-off-by: Thomas Tai <[email protected]>
Reviewed-by: Eric Saint-Etienne <[email protected]>
Signed-off-by: Karl Volz <[email protected]>
Reviewed-by: Keith Busch <[email protected]>
Signed-off-by: Sagi Grimberg <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
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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
...
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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 <[email protected]>
Reviewed-by: Josef Bacik <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
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drivers/md/faulty.c has been renamed to md-faulty.c after
following commit merged int to the main line.
935fe0983e09f4f7331ebf5ea4ae2124f6e9f9e8 .
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 <[email protected]>
Signed-off-by: Jonathan Corbet <[email protected]>
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The CPU hotplug notifiers are history. Remove the last reminders.
Reported-by: Ingo Molnar <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
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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/[email protected]
Signed-off-by: Akinobu Mita <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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/[email protected]
Signed-off-by: Akinobu Mita <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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/[email protected]
Signed-off-by: Akinobu Mita <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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.
[[email protected]: fix build]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Dmitry Vyukov <[email protected]>
Cc: Akinobu Mita <[email protected]>
Cc: Michal Hocko <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Since CHANGEUPPER can now fail, add support for it in the newly
introduced netdev notifier error injection infrastructure.
Signed-off-by: Ido Schimmel <[email protected]>
Signed-off-by: Jiri Pirko <[email protected]>
Acked-by: Nikolay Aleksandrov <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
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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 <[email protected]>
CC: "David S. Miller" <[email protected]>
CC: netdev <[email protected]>
Signed-off-by: Nikolay Aleksandrov <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
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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 <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Darren Hart <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>
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Correct spelling typo in Documentations
Signed-off-by: Jiri Kosina <[email protected]>
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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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Cc: Pavel Machek <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Greg KH <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Dave Jones <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Signed-off-by: Per Forlin <[email protected]>
Reviewed-by: Akinobu Mita <[email protected]>
Signed-off-by: Chris Ball <[email protected]>
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Add description on how to enable random fault injection
for MMC IO.
Signed-off-by: Per Forlin <[email protected]>
Acked-by: Akinobu Mita <[email protected]>
Reviewed-by: Linus Walleij <[email protected]>
Signed-off-by: Chris Ball <[email protected]>
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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().
[[email protected]: extraneous semicolon, per Randy]
Signed-off-by: Akinobu Mita <[email protected]>
Tested-by: Per Forlin <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: Matt Mackall <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: Stephen Rothwell <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Cc: M. Mohan Kumar <[email protected]>
Cc: Americo Wang <[email protected]>
Cc: David Woodhouse <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: "Eric W. Biederman" <[email protected]>,
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Acked-by: Akinobu Mita <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Acked-by : Inaky Perez-Gonzalez <[email protected]>
Reviewed-by : Steven Rostedt <[email protected]>
Reviewed-by : James Smart <[email protected]>
CC: Jiri Kosina <[email protected]>
CC: David Airlie <[email protected]>
CC: Peter Osterlund <[email protected]>
CC: Ananth N Mavinakayanahalli <[email protected]>
CC: Anil S Keshavamurthy <[email protected]>
CC: Masami Hiramatsu <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Correct, disambiguate, and reformat documentation.
Signed-off-by: Don Mullis <[email protected]>
Cc: Akinobu Mita <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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
[[email protected]: reject failure if any caller lies within specified range]
Signed-off-by: Akinobu Mita <[email protected]>
Signed-off-by: Don Mullis <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Signed-off-by: Akinobu Mita <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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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 <[email protected]>
Signed-off-by: Don Mullis <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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