kernel_optimize_test/Documentation/fault-injection/nvme-fault-injection.rst
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.
 -----BEGIN PGP SIGNATURE-----
 
 iQFDBAABCAAtFiEEIw+MvkEiF49krdp9F0NaE2wMflgFAl0krAEPHGNvcmJldEBs
 d24ubmV0AAoJEBdDWhNsDH5Yg98H/AuLqO9LpOgUjF4LhyjxGPdzJkY9RExSJ7km
 gznyreLCZgFaJR+AY6YDsd4Jw6OJlPbu1YM/Qo3C3WrZVFVhgL/s2ebvBgCo50A8
 raAFd8jTf4/mGCHnAqRotAPQ3mETJUk315B66lBJ6Oc+YdpRhwXWq8ZW2bJxInFF
 3HDvoFgMf0KhLuMHUkkL0u3fxH1iA+KvDu8diPbJYFjOdOWENz/CV8wqdVkXRSEW
 DJxIq89h/7d+hIG3d1I7Nw+gibGsAdjSjKv4eRKauZs4Aoxd1Gpl62z0JNk6aT3m
 dtq4joLdwScydonXROD/Twn2jsu4xYTrPwVzChomElMowW/ZBBY=
 =D0eO
 -----END PGP SIGNATURE-----

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

179 lines
6.4 KiB
ReStructuredText
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

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
Example 3: Inject an error into the 10th admin command
------------------------------------------------------
::
echo 100 > /sys/kernel/debug/nvme0/fault_inject/probability
echo 10 > /sys/kernel/debug/nvme0/fault_inject/space
echo 1 > /sys/kernel/debug/nvme0/fault_inject/times
nvme reset /dev/nvme0
Expected Result::
After NVMe controller reset, the reinitialization may or may not succeed.
It depends on which admin command is actually forced to fail.
Message from dmesg::
nvme nvme0: resetting controller
FAULT_INJECTION: forcing a failure.
name fault_inject, interval 1, probability 100, space 1, times 1
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.2.0-rc2+ #2
Hardware name: MSI MS-7A45/B150M MORTAR ARCTIC (MS-7A45), BIOS 1.50 04/25/2017
Call Trace:
<IRQ>
dump_stack+0x63/0x85
should_fail+0x14a/0x170
nvme_should_fail+0x38/0x80 [nvme_core]
nvme_irq+0x129/0x280 [nvme]
? blk_mq_end_request+0xb3/0x120
__handle_irq_event_percpu+0x84/0x1a0
handle_irq_event_percpu+0x32/0x80
handle_irq_event+0x3b/0x60
handle_edge_irq+0x7f/0x1a0
handle_irq+0x20/0x30
do_IRQ+0x4e/0xe0
common_interrupt+0xf/0xf
</IRQ>
RIP: 0010:cpuidle_enter_state+0xc5/0x460
Code: ff e8 8f 5f 86 ff 80 7d c7 00 74 17 9c 58 0f 1f 44 00 00 f6 c4 02 0f 85 69 03 00 00 31 ff e8 62 aa 8c ff fb 66 0f 1f 44 00 00 <45> 85 ed 0f 88 37 03 00 00 4c 8b 45 d0 4c 2b 45 b8 48 ba cf f7 53
RSP: 0018:ffffffff88c03dd0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffffdc
RAX: ffff9dac25a2ac80 RBX: ffffffff88d53760 RCX: 000000000000001f
RDX: 0000000000000000 RSI: 000000002d958403 RDI: 0000000000000000
RBP: ffffffff88c03e18 R08: fffffff75e35ffb7 R09: 00000a49a56c0b48
R10: ffffffff88c03da0 R11: 0000000000001b0c R12: ffff9dac25a34d00
R13: 0000000000000006 R14: 0000000000000006 R15: ffffffff88d53760
cpuidle_enter+0x2e/0x40
call_cpuidle+0x23/0x40
do_idle+0x201/0x280
cpu_startup_entry+0x1d/0x20
rest_init+0xaa/0xb0
arch_call_rest_init+0xe/0x1b
start_kernel+0x51c/0x53b
x86_64_start_reservations+0x24/0x26
x86_64_start_kernel+0x74/0x77
secondary_startup_64+0xa4/0xb0
nvme nvme0: Could not set queue count (16385)
nvme nvme0: IO queues not created