[PATCH 12/57] docs: fault-injection: convert it to ReST format

Mauro Carvalho Chehab
2019-04-16T03:03:02Z

Instead of using plain text, convert it to ReST format, in
order for the docs to be parsed and produce html and pdf output.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
---
.../fault-injection/fault-injection.txt | 265 +++++++++---------
.../fault-injection/notifier-error-inject.txt | 18 +-
.../fault-injection/nvme-fault-injection.txt | 174 ++++++------
.../fault-injection/provoke-crashes.txt | 40 ++-
4 files changed, 263 insertions(+), 234 deletions(-)

diff --git a/Documentation/fault-injection/fault-injection.txt b/Documentation/fault-injection/fault-injection.txt
index a17517a083c3..f51bb21d20e4 100644
--- a/Documentation/fault-injection/fault-injection.txt
+++ b/Documentation/fault-injection/fault-injection.txt
@@ -1,3 +1,4 @@
+===========================================
Fault injection capabilities infrastructure
===========================================

@@ -7,36 +8,36 @@ See also drivers/md/md-faulty.c and "every_nth" module option for scsi_debug.
Available fault injection capabilities
--------------------------------------

-o failslab
+- failslab

injects slab allocation failures. (kmalloc(), kmem_cache_alloc(), ...)

-o fail_page_alloc
+- fail_page_alloc

injects page allocation failures. (alloc_pages(), get_free_pages(), ...)

-o fail_futex
+- fail_futex

injects futex deadlock and uaddr fault errors.

-o fail_make_request
+- fail_make_request

injects disk IO errors on devices permitted by setting
/sys/block/<device>/make-it-fail or
/sys/block/<device>/<partition>/make-it-fail. (generic_make_request())

-o fail_mmc_request
+- fail_mmc_request

injects MMC data errors on devices permitted by setting
debugfs entries under /sys/kernel/debug/mmc0/fail_mmc_request

-o fail_function
+- fail_function

injects error return on specific functions, which are marked by
ALLOW_ERROR_INJECTION() macro, by setting debugfs entries
under /sys/kernel/debug/fail_function. No boot option supported.

-o NVMe fault injection
+- NVMe fault injection

inject NVMe status code and retry flag on devices permitted by setting
debugfs entries under /sys/kernel/debug/nvme*/fault_inject. The default
@@ -47,7 +48,8 @@ o NVMe fault injection
Configure fault-injection capabilities behavior
-----------------------------------------------

-o debugfs entries
+debugfs entries
+^^^^^^^^^^^^^^^

fault-inject-debugfs kernel module provides some debugfs entries for runtime
configuration of fault-injection capabilities.
@@ -55,6 +57,7 @@ configuration of fault-injection capabilities.
- /sys/kernel/debug/fail*/probability:

likelihood of failure injection, in percent.
+
Format: <percent>

Note that one-failure-per-hundred is a very high error rate
@@ -83,6 +86,7 @@ configuration of fault-injection capabilities.
- /sys/kernel/debug/fail*/verbose

Format: { 0 | 1 | 2 }
+
specifies the verbosity of the messages when failure is
injected. '0' means no messages; '1' will print only a single
log line per failure; '2' will print a call trace too -- useful
@@ -91,14 +95,15 @@ configuration of fault-injection capabilities.
- /sys/kernel/debug/fail*/task-filter:

Format: { 'Y' | 'N' }
+
A value of 'N' disables filtering by process (default).
Any positive value limits failures to only processes indicated by
/proc/<pid>/make-it-fail==1.

-- /sys/kernel/debug/fail*/require-start:
-- /sys/kernel/debug/fail*/require-end:
-- /sys/kernel/debug/fail*/reject-start:
-- /sys/kernel/debug/fail*/reject-end:
+- /sys/kernel/debug/fail*/require-start,
+ /sys/kernel/debug/fail*/require-end,
+ /sys/kernel/debug/fail*/reject-start,
+ /sys/kernel/debug/fail*/reject-end:

specifies the range of virtual addresses tested during
stacktrace walking. Failure is injected only if some caller
@@ -116,6 +121,7 @@ configuration of fault-injection capabilities.
- /sys/kernel/debug/fail_page_alloc/ignore-gfp-highmem:

Format: { 'Y' | 'N' }
+
default is 'N', setting it to 'Y' won't inject failures into
highmem/user allocations.

@@ -123,6 +129,7 @@ configuration of fault-injection capabilities.
- /sys/kernel/debug/fail_page_alloc/ignore-gfp-wait:

Format: { 'Y' | 'N' }
+
default is 'N', setting it to 'Y' will inject failures
only into non-sleep allocations (GFP_ATOMIC allocations).

@@ -134,12 +141,14 @@ configuration of fault-injection capabilities.
- /sys/kernel/debug/fail_futex/ignore-private:

Format: { 'Y' | 'N' }
+
default is 'N', setting it to 'Y' will disable failure injections
when dealing with private (address space) futexes.

- /sys/kernel/debug/fail_function/inject:

Format: { 'function-name' | '!function-name' | '' }
+
specifies the target function of error injection by name.
If the function name leads '!' prefix, given function is
removed from injection list. If nothing specified ('')
@@ -160,10 +169,11 @@ configuration of fault-injection capabilities.
function for given function. This will be created when
user specifies new injection entry.

-o Boot option
+Boot option
+^^^^^^^^^^^

In order to inject faults while debugfs is not available (early boot time),
-use the boot option:
+use the boot option::

failslab=
fail_page_alloc=
@@ -171,10 +181,11 @@ use the boot option:
fail_futex=
mmc_core.fail_request=<interval>,<probability>,<space>,<times>

-o proc entries
+proc entries
+^^^^^^^^^^^^

-- /proc/<pid>/fail-nth:
-- /proc/self/task/<tid>/fail-nth:
+- /proc/<pid>/fail-nth,
+ /proc/self/task/<tid>/fail-nth:

Write to this file of integer N makes N-th call in the task fail.
Read from this file returns a integer value. A value of '0' indicates
@@ -191,16 +202,16 @@ o proc entries
How to add new fault injection capability
-----------------------------------------

-o #include <linux/fault-inject.h>
+- #include <linux/fault-inject.h>

-o define the fault attributes
+- define the fault attributes

DECLARE_FAULT_ATTR(name);

Please see the definition of struct fault_attr in fault-inject.h
for details.

-o provide a way to configure fault attributes
+- provide a way to configure fault attributes

- boot option

@@ -222,126 +233,126 @@ o provide a way to configure fault attributes
single kernel module, it is better to provide module parameters to
configure the fault attributes.

-o add a hook to insert failures
+- add a hook to insert failures

- Upon should_fail() returning true, client code should inject a failure.
+ Upon should_fail() returning true, client code should inject a failure:

should_fail(attr, size);

Application Examples
--------------------

-o Inject slab allocation failures into module init/exit code
+- Inject slab allocation failures into module init/exit code::

-#!/bin/bash
+ #!/bin/bash

-FAILTYPE=failslab
-echo Y > /sys/kernel/debug/$FAILTYPE/task-filter
-echo 10 > /sys/kernel/debug/$FAILTYPE/probability
-echo 100 > /sys/kernel/debug/$FAILTYPE/interval
-echo -1 > /sys/kernel/debug/$FAILTYPE/times
-echo 0 > /sys/kernel/debug/$FAILTYPE/space
-echo 2 > /sys/kernel/debug/$FAILTYPE/verbose
-echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-wait
+ FAILTYPE=failslab
+ echo Y > /sys/kernel/debug/$FAILTYPE/task-filter
+ echo 10 > /sys/kernel/debug/$FAILTYPE/probability
+ echo 100 > /sys/kernel/debug/$FAILTYPE/interval
+ echo -1 > /sys/kernel/debug/$FAILTYPE/times
+ echo 0 > /sys/kernel/debug/$FAILTYPE/space
+ echo 2 > /sys/kernel/debug/$FAILTYPE/verbose
+ echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-wait

-faulty_system()
-{
+ faulty_system()
+ {
bash -c "echo 1 > /proc/self/make-it-fail && exec $*"
-}
+ }

-if [ $# -eq 0 ]
-then
+ if [ $# -eq 0 ]
+ then
echo "Usage: $0 modulename [ modulename ... ]"
exit 1
-fi
+ fi

-for m in $*
-do
+ for m in $*
+ do
echo inserting $m...
faulty_system modprobe $m

echo removing $m...
faulty_system modprobe -r $m
-done
+ done

------------------------------------------------------------------------------

-o Inject page allocation failures only for a specific module
+- Inject page allocation failures only for a specific module::

-#!/bin/bash
+ #!/bin/bash

-FAILTYPE=fail_page_alloc
-module=$1
+ FAILTYPE=fail_page_alloc
+ module=$1

-if [ -z $module ]
-then
+ if [ -z $module ]
+ then
echo "Usage: $0 <modulename>"
exit 1
-fi
+ fi

-modprobe $module
+ modprobe $module

-if [ ! -d /sys/module/$module/sections ]
-then
+ if [ ! -d /sys/module/$module/sections ]
+ then
echo Module $module is not loaded
exit 1
-fi
+ fi

-cat /sys/module/$module/sections/.text > /sys/kernel/debug/$FAILTYPE/require-start
-cat /sys/module/$module/sections/.data > /sys/kernel/debug/$FAILTYPE/require-end
+ cat /sys/module/$module/sections/.text > /sys/kernel/debug/$FAILTYPE/require-start
+ cat /sys/module/$module/sections/.data > /sys/kernel/debug/$FAILTYPE/require-end

-echo N > /sys/kernel/debug/$FAILTYPE/task-filter
-echo 10 > /sys/kernel/debug/$FAILTYPE/probability
-echo 100 > /sys/kernel/debug/$FAILTYPE/interval
-echo -1 > /sys/kernel/debug/$FAILTYPE/times
-echo 0 > /sys/kernel/debug/$FAILTYPE/space
-echo 2 > /sys/kernel/debug/$FAILTYPE/verbose
-echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-wait
-echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-highmem
-echo 10 > /sys/kernel/debug/$FAILTYPE/stacktrace-depth
+ echo N > /sys/kernel/debug/$FAILTYPE/task-filter
+ echo 10 > /sys/kernel/debug/$FAILTYPE/probability
+ echo 100 > /sys/kernel/debug/$FAILTYPE/interval
+ echo -1 > /sys/kernel/debug/$FAILTYPE/times
+ echo 0 > /sys/kernel/debug/$FAILTYPE/space
+ echo 2 > /sys/kernel/debug/$FAILTYPE/verbose
+ echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-wait
+ echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-highmem
+ echo 10 > /sys/kernel/debug/$FAILTYPE/stacktrace-depth

-trap "echo 0 > /sys/kernel/debug/$FAILTYPE/probability" SIGINT SIGTERM EXIT
+ trap "echo 0 > /sys/kernel/debug/$FAILTYPE/probability" SIGINT SIGTERM EXIT

-echo "Injecting errors into the module $module... (interrupt to stop)"
-sleep 1000000
+ echo "Injecting errors into the module $module... (interrupt to stop)"
+ sleep 1000000

------------------------------------------------------------------------------

-o Inject open_ctree error while btrfs mount
+- Inject open_ctree error while btrfs mount::

-#!/bin/bash
+ #!/bin/bash

-rm -f testfile.img
-dd if=/dev/zero of=testfile.img bs=1M seek=1000 count=1
-DEVICE=$(losetup --show -f testfile.img)
-mkfs.btrfs -f $DEVICE
-mkdir -p tmpmnt
+ rm -f testfile.img
+ dd if=/dev/zero of=testfile.img bs=1M seek=1000 count=1
+ DEVICE=$(losetup --show -f testfile.img)
+ mkfs.btrfs -f $DEVICE
+ mkdir -p tmpmnt

-FAILTYPE=fail_function
-FAILFUNC=open_ctree
-echo $FAILFUNC > /sys/kernel/debug/$FAILTYPE/inject
-echo -12 > /sys/kernel/debug/$FAILTYPE/$FAILFUNC/retval
-echo N > /sys/kernel/debug/$FAILTYPE/task-filter
-echo 100 > /sys/kernel/debug/$FAILTYPE/probability
-echo 0 > /sys/kernel/debug/$FAILTYPE/interval
-echo -1 > /sys/kernel/debug/$FAILTYPE/times
-echo 0 > /sys/kernel/debug/$FAILTYPE/space
-echo 1 > /sys/kernel/debug/$FAILTYPE/verbose
+ FAILTYPE=fail_function
+ FAILFUNC=open_ctree
+ echo $FAILFUNC > /sys/kernel/debug/$FAILTYPE/inject
+ echo -12 > /sys/kernel/debug/$FAILTYPE/$FAILFUNC/retval
+ echo N > /sys/kernel/debug/$FAILTYPE/task-filter
+ echo 100 > /sys/kernel/debug/$FAILTYPE/probability
+ echo 0 > /sys/kernel/debug/$FAILTYPE/interval
+ echo -1 > /sys/kernel/debug/$FAILTYPE/times
+ echo 0 > /sys/kernel/debug/$FAILTYPE/space
+ echo 1 > /sys/kernel/debug/$FAILTYPE/verbose

-mount -t btrfs $DEVICE tmpmnt
-if [ $? -ne 0 ]
-then
+ mount -t btrfs $DEVICE tmpmnt
+ if [ $? -ne 0 ]
+ then
echo "SUCCESS!"
-else
+ else
echo "FAILED!"
umount tmpmnt
-fi
+ fi

-echo > /sys/kernel/debug/$FAILTYPE/inject
+ echo > /sys/kernel/debug/$FAILTYPE/inject

-rmdir tmpmnt
-losetup -d $DEVICE
-rm testfile.img
+ rmdir tmpmnt
+ losetup -d $DEVICE
+ rm testfile.img

Tool to run command with failslab or fail_page_alloc
@@ -354,43 +365,43 @@ see the following examples.
Examples:

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

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

Systematic faults using fail-nth
---------------------------------

The following code systematically faults 0-th, 1-st, 2-nd and so on
-capabilities in the socketpair() system call.
+capabilities in the socketpair() system call::

-#include <sys/types.h>
-#include <sys/stat.h>
-#include <sys/socket.h>
-#include <sys/syscall.h>
-#include <fcntl.h>
-#include <unistd.h>
-#include <string.h>
-#include <stdlib.h>
-#include <stdio.h>
-#include <errno.h>
+ #include <sys/types.h>
+ #include <sys/stat.h>
+ #include <sys/socket.h>
+ #include <sys/syscall.h>
+ #include <fcntl.h>
+ #include <unistd.h>
+ #include <string.h>
+ #include <stdlib.h>
+ #include <stdio.h>
+ #include <errno.h>

-int main()
-{
+ int main()
+ {
int i, err, res, fail_nth, fds[2];
char buf[128];

@@ -413,23 +424,23 @@ int main()
break;
}
return 0;
-}
+ }

-An example output:
+An example output::

-1-th fault Y: res=-1/23
-2-th fault Y: res=-1/23
-3-th fault Y: res=-1/12
-4-th fault Y: res=-1/12
-5-th fault Y: res=-1/23
-6-th fault Y: res=-1/23
-7-th fault Y: res=-1/23
-8-th fault Y: res=-1/12
-9-th fault Y: res=-1/12
-10-th fault Y: res=-1/12
-11-th fault Y: res=-1/12
-12-th fault Y: res=-1/12
-13-th fault Y: res=-1/12
-14-th fault Y: res=-1/12
-15-th fault Y: res=-1/12
-16-th fault N: res=0/12
+ 1-th fault Y: res=-1/23
+ 2-th fault Y: res=-1/23
+ 3-th fault Y: res=-1/12
+ 4-th fault Y: res=-1/12
+ 5-th fault Y: res=-1/23
+ 6-th fault Y: res=-1/23
+ 7-th fault Y: res=-1/23
+ 8-th fault Y: res=-1/12
+ 9-th fault Y: res=-1/12
+ 10-th fault Y: res=-1/12
+ 11-th fault Y: res=-1/12
+ 12-th fault Y: res=-1/12
+ 13-th fault Y: res=-1/12
+ 14-th fault Y: res=-1/12
+ 15-th fault Y: res=-1/12
+ 16-th fault N: res=0/12
diff --git a/Documentation/fault-injection/notifier-error-inject.txt b/Documentation/fault-injection/notifier-error-inject.txt
index e861d761de24..1668b6e48d3a 100644
--- a/Documentation/fault-injection/notifier-error-inject.txt
+++ b/Documentation/fault-injection/notifier-error-inject.txt
@@ -14,7 +14,8 @@ modules that can be used to test the following notifiers.
PM notifier error injection module
----------------------------------
This feature is controlled through debugfs interface
-/sys/kernel/debug/notifier-error-inject/pm/actions/<notifier event>/error
+
+ /sys/kernel/debug/notifier-error-inject/pm/actions/<notifier event>/error

Possible PM notifier events to be failed are:

@@ -22,7 +23,7 @@ Possible PM notifier events to be failed are:
* PM_SUSPEND_PREPARE
* PM_RESTORE_PREPARE

-Example: Inject PM suspend error (-12 = -ENOMEM)
+Example: Inject PM suspend error (-12 = -ENOMEM)::

# cd /sys/kernel/debug/notifier-error-inject/pm/
# echo -12 > actions/PM_SUSPEND_PREPARE/error
@@ -32,14 +33,15 @@ Example: Inject PM suspend error (-12 = -ENOMEM)
Memory hotplug notifier error injection module
----------------------------------------------
This feature is controlled through debugfs interface
-/sys/kernel/debug/notifier-error-inject/memory/actions/<notifier event>/error
+
+ /sys/kernel/debug/notifier-error-inject/memory/actions/<notifier event>/error

Possible memory notifier events to be failed are:

* MEM_GOING_ONLINE
* MEM_GOING_OFFLINE

-Example: Inject memory hotplug offline error (-12 == -ENOMEM)
+Example: Inject memory hotplug offline error (-12 == -ENOMEM)::

# cd /sys/kernel/debug/notifier-error-inject/memory
# echo -12 > actions/MEM_GOING_OFFLINE/error
@@ -49,7 +51,8 @@ Example: Inject memory hotplug offline error (-12 == -ENOMEM)
powerpc pSeries reconfig notifier error injection module
--------------------------------------------------------
This feature is controlled through debugfs interface
-/sys/kernel/debug/notifier-error-inject/pSeries-reconfig/actions/<notifier event>/error
+
+ /sys/kernel/debug/notifier-error-inject/pSeries-reconfig/actions/<notifier event>/error

Possible pSeries reconfig notifier events to be failed are:

@@ -61,7 +64,8 @@ Possible pSeries reconfig notifier events to be failed are:
Netdevice notifier error injection module
----------------------------------------------
This feature is controlled through debugfs interface
-/sys/kernel/debug/notifier-error-inject/netdev/actions/<notifier event>/error
+
+ /sys/kernel/debug/notifier-error-inject/netdev/actions/<notifier event>/error

Netdevice notifier events which can be failed are:

@@ -75,7 +79,7 @@ Netdevice notifier events which can be failed are:
* NETDEV_PRECHANGEUPPER
* NETDEV_CHANGEUPPER

-Example: Inject netdevice mtu change error (-22 == -EINVAL)
+Example: Inject netdevice mtu change error (-22 == -EINVAL)::

# cd /sys/kernel/debug/notifier-error-inject/netdev
# echo -22 > actions/NETDEV_CHANGEMTU/error
diff --git a/Documentation/fault-injection/nvme-fault-injection.txt b/Documentation/fault-injection/nvme-fault-injection.txt
index 8fbf3bf60b62..bbb1bf3e8650 100644
--- a/Documentation/fault-injection/nvme-fault-injection.txt
+++ b/Documentation/fault-injection/nvme-fault-injection.txt
@@ -16,101 +16,105 @@ following.
Example 1: Inject default status code with no retry
---------------------------------------------------

-mount /dev/nvme0n1 /mnt
-echo 1 > /sys/kernel/debug/nvme0n1/fault_inject/times
-echo 100 > /sys/kernel/debug/nvme0n1/fault_inject/probability
-cp a.file /mnt
+::

-Expected Result:
+ mount /dev/nvme0n1 /mnt
+ echo 1 > /sys/kernel/debug/nvme0n1/fault_inject/times
+ echo 100 > /sys/kernel/debug/nvme0n1/fault_inject/probability
+ cp a.file /mnt

-cp: cannot stat ‘/mnt/a.file’: Input/output error
+Expected Result::

-Message from dmesg:
+ cp: cannot stat ‘/mnt/a.file’: Input/output error

-FAULT_INJECTION: forcing a failure.
-name fault_inject, interval 1, probability 100, space 0, times 1
-CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.15.0-rc8+ #2
-Hardware name: innotek GmbH VirtualBox/VirtualBox,
-BIOS VirtualBox 12/01/2006
-Call Trace:
- <IRQ>
- dump_stack+0x5c/0x7d
- should_fail+0x148/0x170
- nvme_should_fail+0x2f/0x50 [nvme_core]
- nvme_process_cq+0xe7/0x1d0 [nvme]
- nvme_irq+0x1e/0x40 [nvme]
- __handle_irq_event_percpu+0x3a/0x190
- handle_irq_event_percpu+0x30/0x70
- handle_irq_event+0x36/0x60
- handle_fasteoi_irq+0x78/0x120
- handle_irq+0xa7/0x130
- ? tick_irq_enter+0xa8/0xc0
- do_IRQ+0x43/0xc0
- common_interrupt+0xa2/0xa2
- </IRQ>
-RIP: 0010:native_safe_halt+0x2/0x10
-RSP: 0018:ffffffff82003e90 EFLAGS: 00000246 ORIG_RAX: ffffffffffffffdd
-RAX: ffffffff817a10c0 RBX: ffffffff82012480 RCX: 0000000000000000
-RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
-RBP: 0000000000000000 R08: 000000008e38ce64 R09: 0000000000000000
-R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff82012480
-R13: ffffffff82012480 R14: 0000000000000000 R15: 0000000000000000
- ? __sched_text_end+0x4/0x4
- default_idle+0x18/0xf0
- do_idle+0x150/0x1d0
- cpu_startup_entry+0x6f/0x80
- start_kernel+0x4c4/0x4e4
- ? set_init_arg+0x55/0x55
- secondary_startup_64+0xa5/0xb0
- print_req_error: I/O error, dev nvme0n1, sector 9240
-EXT4-fs error (device nvme0n1): ext4_find_entry:1436:
-inode #2: comm cp: reading directory lblock 0
+Message from dmesg::
+
+ FAULT_INJECTION: forcing a failure.
+ name fault_inject, interval 1, probability 100, space 0, times 1
+ CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.15.0-rc8+ #2
+ Hardware name: innotek GmbH VirtualBox/VirtualBox,
+ BIOS VirtualBox 12/01/2006
+ Call Trace:
+ <IRQ>
+ dump_stack+0x5c/0x7d
+ should_fail+0x148/0x170
+ nvme_should_fail+0x2f/0x50 [nvme_core]
+ nvme_process_cq+0xe7/0x1d0 [nvme]
+ nvme_irq+0x1e/0x40 [nvme]
+ __handle_irq_event_percpu+0x3a/0x190
+ handle_irq_event_percpu+0x30/0x70
+ handle_irq_event+0x36/0x60
+ handle_fasteoi_irq+0x78/0x120
+ handle_irq+0xa7/0x130
+ ? tick_irq_enter+0xa8/0xc0
+ do_IRQ+0x43/0xc0
+ common_interrupt+0xa2/0xa2
+ </IRQ>
+ RIP: 0010:native_safe_halt+0x2/0x10
+ RSP: 0018:ffffffff82003e90 EFLAGS: 00000246 ORIG_RAX: ffffffffffffffdd
+ RAX: ffffffff817a10c0 RBX: ffffffff82012480 RCX: 0000000000000000
+ RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
+ RBP: 0000000000000000 R08: 000000008e38ce64 R09: 0000000000000000
+ R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff82012480
+ R13: ffffffff82012480 R14: 0000000000000000 R15: 0000000000000000
+ ? __sched_text_end+0x4/0x4
+ default_idle+0x18/0xf0
+ do_idle+0x150/0x1d0
+ cpu_startup_entry+0x6f/0x80
+ start_kernel+0x4c4/0x4e4
+ ? set_init_arg+0x55/0x55
+ secondary_startup_64+0xa5/0xb0
+ print_req_error: I/O error, dev nvme0n1, sector 9240
+ EXT4-fs error (device nvme0n1): ext4_find_entry:1436:
+ inode #2: comm cp: reading directory lblock 0

Example 2: Inject default status code with retry
------------------------------------------------

-mount /dev/nvme0n1 /mnt
-echo 1 > /sys/kernel/debug/nvme0n1/fault_inject/times
-echo 100 > /sys/kernel/debug/nvme0n1/fault_inject/probability
-echo 1 > /sys/kernel/debug/nvme0n1/fault_inject/status
-echo 0 > /sys/kernel/debug/nvme0n1/fault_inject/dont_retry
+::

-cp a.file /mnt
+ mount /dev/nvme0n1 /mnt
+ echo 1 > /sys/kernel/debug/nvme0n1/fault_inject/times
+ echo 100 > /sys/kernel/debug/nvme0n1/fault_inject/probability
+ echo 1 > /sys/kernel/debug/nvme0n1/fault_inject/status
+ echo 0 > /sys/kernel/debug/nvme0n1/fault_inject/dont_retry

-Expected Result:
+ cp a.file /mnt

-command success without error
+Expected Result::

-Message from dmesg:
+ command success without error

-FAULT_INJECTION: forcing a failure.
-name fault_inject, interval 1, probability 100, space 0, times 1
-CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.15.0-rc8+ #4
-Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
-Call Trace:
- <IRQ>
- dump_stack+0x5c/0x7d
- should_fail+0x148/0x170
- nvme_should_fail+0x30/0x60 [nvme_core]
- nvme_loop_queue_response+0x84/0x110 [nvme_loop]
- nvmet_req_complete+0x11/0x40 [nvmet]
- nvmet_bio_done+0x28/0x40 [nvmet]
- blk_update_request+0xb0/0x310
- blk_mq_end_request+0x18/0x60
- flush_smp_call_function_queue+0x3d/0xf0
- smp_call_function_single_interrupt+0x2c/0xc0
- call_function_single_interrupt+0xa2/0xb0
- </IRQ>
-RIP: 0010:native_safe_halt+0x2/0x10
-RSP: 0018:ffffc9000068bec0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff04
-RAX: ffffffff817a10c0 RBX: ffff88011a3c9680 RCX: 0000000000000000
-RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
-RBP: 0000000000000001 R08: 000000008e38c131 R09: 0000000000000000
-R10: 0000000000000000 R11: 0000000000000000 R12: ffff88011a3c9680
-R13: ffff88011a3c9680 R14: 0000000000000000 R15: 0000000000000000
- ? __sched_text_end+0x4/0x4
- default_idle+0x18/0xf0
- do_idle+0x150/0x1d0
- cpu_startup_entry+0x6f/0x80
- start_secondary+0x187/0x1e0
- secondary_startup_64+0xa5/0xb0
+Message from dmesg::
+
+ FAULT_INJECTION: forcing a failure.
+ name fault_inject, interval 1, probability 100, space 0, times 1
+ CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.15.0-rc8+ #4
+ Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
+ Call Trace:
+ <IRQ>
+ dump_stack+0x5c/0x7d
+ should_fail+0x148/0x170
+ nvme_should_fail+0x30/0x60 [nvme_core]
+ nvme_loop_queue_response+0x84/0x110 [nvme_loop]
+ nvmet_req_complete+0x11/0x40 [nvmet]
+ nvmet_bio_done+0x28/0x40 [nvmet]
+ blk_update_request+0xb0/0x310
+ blk_mq_end_request+0x18/0x60
+ flush_smp_call_function_queue+0x3d/0xf0
+ smp_call_function_single_interrupt+0x2c/0xc0
+ call_function_single_interrupt+0xa2/0xb0
+ </IRQ>
+ RIP: 0010:native_safe_halt+0x2/0x10
+ RSP: 0018:ffffc9000068bec0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff04
+ RAX: ffffffff817a10c0 RBX: ffff88011a3c9680 RCX: 0000000000000000
+ RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
+ RBP: 0000000000000001 R08: 000000008e38c131 R09: 0000000000000000
+ R10: 0000000000000000 R11: 0000000000000000 R12: ffff88011a3c9680
+ R13: ffff88011a3c9680 R14: 0000000000000000 R15: 0000000000000000
+ ? __sched_text_end+0x4/0x4
+ default_idle+0x18/0xf0
+ do_idle+0x150/0x1d0
+ cpu_startup_entry+0x6f/0x80
+ start_secondary+0x187/0x1e0
+ secondary_startup_64+0xa5/0xb0
diff --git a/Documentation/fault-injection/provoke-crashes.txt b/Documentation/fault-injection/provoke-crashes.txt
index 7a9d3d81525b..9279a3e12278 100644
--- a/Documentation/fault-injection/provoke-crashes.txt
+++ b/Documentation/fault-injection/provoke-crashes.txt
@@ -1,3 +1,7 @@
+===============
+Provoke crashes
+===============
+
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
@@ -8,31 +12,37 @@ support.
You can provide the way either through module arguments when inserting
the module, or through a debugfs interface.

-Usage: insmod lkdtm.ko [recur_count={>0}] cpoint_name=<> cpoint_type=<>
- [cpoint_count={>0}]
+Usage::

- recur_count : Recursion level for the stack overflow test. Default is 10.
+ insmod lkdtm.ko [recur_count={>0}] cpoint_name=<> cpoint_type=<>
+ [cpoint_count={>0}]

- cpoint_name : Crash point where the kernel is to be crashed. 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
+recur_count
+ Recursion level for the stack overflow test. Default is 10.

- 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,
+cpoint_name
+ Crash point where the kernel is to be crashed. 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

- cpoint_count : Indicates the number of times the crash point is to be hit
- to trigger an action. The default is 10.
+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,
+
+cpoint_count
+ Indicates the number of times the crash point is to be hit
+ to trigger an action. The default is 10.

You can also induce failures by mounting debugfs and writing the type to
-<mountpoint>/provoke-crash/<crashpoint>. E.g.,
+<mountpoint>/provoke-crash/<crashpoint>. E.g.::

mount -t debugfs debugfs /mnt
echo EXCEPTION > /mnt/provoke-crash/INT_HARDWARE_ENTRY

-A special file is `DIRECT' which will induce the crash directly without
+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.
--
2.20.1