nvme-fault-injection.rst (6535B)
1NVMe Fault Injection 2==================== 3Linux's fault injection framework provides a systematic way to support 4error injection via debugfs in the /sys/kernel/debug directory. When 5enabled, the default NVME_SC_INVALID_OPCODE with no retry will be 6injected into the nvme_try_complete_req. Users can change the default status 7code and no retry flag via the debugfs. The list of Generic Command 8Status can be found in include/linux/nvme.h 9 10Following examples show how to inject an error into the nvme. 11 12First, enable CONFIG_FAULT_INJECTION_DEBUG_FS kernel config, 13recompile the kernel. After booting up the kernel, do the 14following. 15 16Example 1: Inject default status code with no retry 17--------------------------------------------------- 18 19:: 20 21 mount /dev/nvme0n1 /mnt 22 echo 1 > /sys/kernel/debug/nvme0n1/fault_inject/times 23 echo 100 > /sys/kernel/debug/nvme0n1/fault_inject/probability 24 cp a.file /mnt 25 26Expected Result:: 27 28 cp: cannot stat ‘/mnt/a.file’: Input/output error 29 30Message from dmesg:: 31 32 FAULT_INJECTION: forcing a failure. 33 name fault_inject, interval 1, probability 100, space 0, times 1 34 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.15.0-rc8+ #2 35 Hardware name: innotek GmbH VirtualBox/VirtualBox, 36 BIOS VirtualBox 12/01/2006 37 Call Trace: 38 <IRQ> 39 dump_stack+0x5c/0x7d 40 should_fail+0x148/0x170 41 nvme_should_fail+0x2f/0x50 [nvme_core] 42 nvme_process_cq+0xe7/0x1d0 [nvme] 43 nvme_irq+0x1e/0x40 [nvme] 44 __handle_irq_event_percpu+0x3a/0x190 45 handle_irq_event_percpu+0x30/0x70 46 handle_irq_event+0x36/0x60 47 handle_fasteoi_irq+0x78/0x120 48 handle_irq+0xa7/0x130 49 ? tick_irq_enter+0xa8/0xc0 50 do_IRQ+0x43/0xc0 51 common_interrupt+0xa2/0xa2 52 </IRQ> 53 RIP: 0010:native_safe_halt+0x2/0x10 54 RSP: 0018:ffffffff82003e90 EFLAGS: 00000246 ORIG_RAX: ffffffffffffffdd 55 RAX: ffffffff817a10c0 RBX: ffffffff82012480 RCX: 0000000000000000 56 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 57 RBP: 0000000000000000 R08: 000000008e38ce64 R09: 0000000000000000 58 R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff82012480 59 R13: ffffffff82012480 R14: 0000000000000000 R15: 0000000000000000 60 ? __sched_text_end+0x4/0x4 61 default_idle+0x18/0xf0 62 do_idle+0x150/0x1d0 63 cpu_startup_entry+0x6f/0x80 64 start_kernel+0x4c4/0x4e4 65 ? set_init_arg+0x55/0x55 66 secondary_startup_64+0xa5/0xb0 67 print_req_error: I/O error, dev nvme0n1, sector 9240 68 EXT4-fs error (device nvme0n1): ext4_find_entry:1436: 69 inode #2: comm cp: reading directory lblock 0 70 71Example 2: Inject default status code with retry 72------------------------------------------------ 73 74:: 75 76 mount /dev/nvme0n1 /mnt 77 echo 1 > /sys/kernel/debug/nvme0n1/fault_inject/times 78 echo 100 > /sys/kernel/debug/nvme0n1/fault_inject/probability 79 echo 1 > /sys/kernel/debug/nvme0n1/fault_inject/status 80 echo 0 > /sys/kernel/debug/nvme0n1/fault_inject/dont_retry 81 82 cp a.file /mnt 83 84Expected Result:: 85 86 command success without error 87 88Message from dmesg:: 89 90 FAULT_INJECTION: forcing a failure. 91 name fault_inject, interval 1, probability 100, space 0, times 1 92 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.15.0-rc8+ #4 93 Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 94 Call Trace: 95 <IRQ> 96 dump_stack+0x5c/0x7d 97 should_fail+0x148/0x170 98 nvme_should_fail+0x30/0x60 [nvme_core] 99 nvme_loop_queue_response+0x84/0x110 [nvme_loop] 100 nvmet_req_complete+0x11/0x40 [nvmet] 101 nvmet_bio_done+0x28/0x40 [nvmet] 102 blk_update_request+0xb0/0x310 103 blk_mq_end_request+0x18/0x60 104 flush_smp_call_function_queue+0x3d/0xf0 105 smp_call_function_single_interrupt+0x2c/0xc0 106 call_function_single_interrupt+0xa2/0xb0 107 </IRQ> 108 RIP: 0010:native_safe_halt+0x2/0x10 109 RSP: 0018:ffffc9000068bec0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff04 110 RAX: ffffffff817a10c0 RBX: ffff88011a3c9680 RCX: 0000000000000000 111 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 112 RBP: 0000000000000001 R08: 000000008e38c131 R09: 0000000000000000 113 R10: 0000000000000000 R11: 0000000000000000 R12: ffff88011a3c9680 114 R13: ffff88011a3c9680 R14: 0000000000000000 R15: 0000000000000000 115 ? __sched_text_end+0x4/0x4 116 default_idle+0x18/0xf0 117 do_idle+0x150/0x1d0 118 cpu_startup_entry+0x6f/0x80 119 start_secondary+0x187/0x1e0 120 secondary_startup_64+0xa5/0xb0 121 122Example 3: Inject an error into the 10th admin command 123------------------------------------------------------ 124 125:: 126 127 echo 100 > /sys/kernel/debug/nvme0/fault_inject/probability 128 echo 10 > /sys/kernel/debug/nvme0/fault_inject/space 129 echo 1 > /sys/kernel/debug/nvme0/fault_inject/times 130 nvme reset /dev/nvme0 131 132Expected Result:: 133 134 After NVMe controller reset, the reinitialization may or may not succeed. 135 It depends on which admin command is actually forced to fail. 136 137Message from dmesg:: 138 139 nvme nvme0: resetting controller 140 FAULT_INJECTION: forcing a failure. 141 name fault_inject, interval 1, probability 100, space 1, times 1 142 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.2.0-rc2+ #2 143 Hardware name: MSI MS-7A45/B150M MORTAR ARCTIC (MS-7A45), BIOS 1.50 04/25/2017 144 Call Trace: 145 <IRQ> 146 dump_stack+0x63/0x85 147 should_fail+0x14a/0x170 148 nvme_should_fail+0x38/0x80 [nvme_core] 149 nvme_irq+0x129/0x280 [nvme] 150 ? blk_mq_end_request+0xb3/0x120 151 __handle_irq_event_percpu+0x84/0x1a0 152 handle_irq_event_percpu+0x32/0x80 153 handle_irq_event+0x3b/0x60 154 handle_edge_irq+0x7f/0x1a0 155 handle_irq+0x20/0x30 156 do_IRQ+0x4e/0xe0 157 common_interrupt+0xf/0xf 158 </IRQ> 159 RIP: 0010:cpuidle_enter_state+0xc5/0x460 160 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 53 161 RSP: 0018:ffffffff88c03dd0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffffdc 162 RAX: ffff9dac25a2ac80 RBX: ffffffff88d53760 RCX: 000000000000001f 163 RDX: 0000000000000000 RSI: 000000002d958403 RDI: 0000000000000000 164 RBP: ffffffff88c03e18 R08: fffffff75e35ffb7 R09: 00000a49a56c0b48 165 R10: ffffffff88c03da0 R11: 0000000000001b0c R12: ffff9dac25a34d00 166 R13: 0000000000000006 R14: 0000000000000006 R15: ffffffff88d53760 167 cpuidle_enter+0x2e/0x40 168 call_cpuidle+0x23/0x40 169 do_idle+0x201/0x280 170 cpu_startup_entry+0x1d/0x20 171 rest_init+0xaa/0xb0 172 arch_call_rest_init+0xe/0x1b 173 start_kernel+0x51c/0x53b 174 x86_64_start_reservations+0x24/0x26 175 x86_64_start_kernel+0x74/0x77 176 secondary_startup_64+0xa4/0xb0 177 nvme nvme0: Could not set queue count (16385) 178 nvme nvme0: IO queues not created