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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>
This commit is contained in:
Mauro Carvalho Chehab 2019-06-12 14:52:44 -03:00 committed by Jonathan Corbet
parent f0ba43774c
commit 10ffebbed5
14 changed files with 344 additions and 295 deletions
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265
Documentation/fault-injection/fault-injection.txt → Documentation/fault-injection/fault-injection.rst
View File

@ -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

20
Documentation/fault-injection/index.rst Normal file
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@ -0,0 +1,20 @@
:orphan:
===============
fault-injection
===============
.. toctree::
:maxdepth: 1
fault-injection
notifier-error-inject
nvme-fault-injection
provoke-crashes
.. only:: subproject and html
Indices
=======
* :ref:`genindex`

18
Documentation/fault-injection/notifier-error-inject.txt → Documentation/fault-injection/notifier-error-inject.rst
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@ -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

120
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@ -0,0 +1,120 @@
NVMe Fault Injection
====================
Linux's fault injection framework provides a systematic way to support
error injection via debugfs in the /sys/kernel/debug directory. When
enabled, the default NVME_SC_INVALID_OPCODE with no retry will be
injected into the nvme_end_request. Users can change the default status
code and no retry flag via the debugfs. The list of Generic Command
Status can be found in include/linux/nvme.h
Following examples show how to inject an error into the nvme.
First, enable CONFIG_FAULT_INJECTION_DEBUG_FS kernel config,
recompile the kernel. After booting up the kernel, do the
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::
cp: cannot stat ‘/mnt/a.file’: Input/output error
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
Expected Result::
command success without error
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

116
Documentation/fault-injection/nvme-fault-injection.txt
View File

@ -1,116 +0,0 @@
NVMe Fault Injection
====================
Linux's fault injection framework provides a systematic way to support
error injection via debugfs in the /sys/kernel/debug directory. When
enabled, the default NVME_SC_INVALID_OPCODE with no retry will be
injected into the nvme_end_request. Users can change the default status
code and no retry flag via the debugfs. The list of Generic Command
Status can be found in include/linux/nvme.h
Following examples show how to inject an error into the nvme.
First, enable CONFIG_FAULT_INJECTION_DEBUG_FS kernel config,
recompile the kernel. After booting up the kernel, do the
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:
cp: cannot stat ‘/mnt/a.file’: Input/output error
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
Expected Result:
command success without error
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

48
Documentation/fault-injection/provoke-crashes.rst Normal file
View File

@ -0,0 +1,48 @@
===============
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
crashing points, but can also crash the kernel directly without KRPOBE
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}]
recur_count
Recursion level for the stack overflow test. Default is 10.
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_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.::
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
KPROBE instrumentation. This mode is the only one available when the module
is built on a kernel without KPROBEs support.

38
Documentation/fault-injection/provoke-crashes.txt
View File

@ -1,38 +0,0 @@
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.
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}]
recur_count : Recursion level for the stack overflow test. Default is 10.
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_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.,
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
KPROBE instrumentation. This mode is the only one available when the module
is built on a kernel without KPROBEs support.

2
Documentation/process/4.Coding.rst
View File

@ -298,7 +298,7 @@ enabled, a configurable percentage of memory allocations will be made to
fail; these failures can be restricted to a specific range of code.
Running with fault injection enabled allows the programmer to see how the
code responds when things go badly. See
Documentation/fault-injection/fault-injection.txt for more information on
Documentation/fault-injection/fault-injection.rst for more information on
how to use this facility.
Other kinds of errors can be found with the "sparse" static analysis tool.

2
Documentation/translations/it_IT/process/4.Coding.rst
View File

@ -314,7 +314,7 @@ di allocazione di memoria sarà destinata al fallimento; questi fallimenti
possono essere ridotti ad uno specifico pezzo di codice. Procedere con
l'inserimento dei fallimenti attivo permette al programmatore di verificare
come il codice risponde quando le cose vanno male. Consultate:
Documentation/fault-injection/fault-injection.txt per avere maggiori
Documentation/fault-injection/fault-injection.rst per avere maggiori
informazioni su come utilizzare questo strumento.
Altre tipologie di errori possono essere riscontrati con lo strumento di

2
Documentation/translations/zh_CN/process/4.Coding.rst
View File

@ -205,7 +205,7 @@ Linus对这个问题给出了最佳答案:
启用故障注入后，内存分配的可配置百分比将失败；这些失败可以限制在特定的代码
范围内。在启用了故障注入的情况下运行，程序员可以看到当情况恶化时代码如何响
应。有关如何使用此工具的详细信息，请参阅
Documentation/fault-injection/fault-injection.txt。
Documentation/fault-injection/fault-injection.rst。
使用“sparse”静态分析工具可以发现其他类型的错误。对于sparse，可以警告程序员
用户空间和内核空间地址之间的混淆、big endian和small endian数量的混合、在需

2
drivers/misc/lkdtm/core.c
View File

@ -15,7 +15,7 @@
*
* Debugfs support added by Simon Kagstrom <simon.kagstrom@netinsight.net>
*
* See Documentation/fault-injection/provoke-crashes.txt for instructions
* See Documentation/fault-injection/provoke-crashes.rst for instructions
*/
#include "lkdtm.h"
#include <linux/fs.h>

2
include/linux/fault-inject.h
View File

@ -11,7 +11,7 @@
/*
* For explanation of the elements of this struct, see
* Documentation/fault-injection/fault-injection.txt
* Documentation/fault-injection/fault-injection.rst
*/
struct fault_attr {
unsigned long probability;

2
lib/Kconfig.debug
View File

@ -1701,7 +1701,7 @@ config LKDTM
called lkdtm.
Documentation on how to use the module can be found in
Documentation/fault-injection/provoke-crashes.txt
Documentation/fault-injection/provoke-crashes.rst
config TEST_LIST_SORT
tristate "Linked list sorting test"

2
tools/testing/fault-injection/failcmd.sh
View File

@ -42,7 +42,7 @@ OPTIONS
--interval=value, --space=value, --verbose=value, --task-filter=value,
--stacktrace-depth=value, --require-start=value, --require-end=value,
--reject-start=value, --reject-end=value, --ignore-gfp-wait=value
See Documentation/fault-injection/fault-injection.txt for more
See Documentation/fault-injection/fault-injection.rst for more
information
failslab options: