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| -rw-r--r-- | Documentation/fault-injection/nvme-fault-injection.rst | 178 |
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diff --git a/Documentation/fault-injection/nvme-fault-injection.rst b/Documentation/fault-injection/nvme-fault-injection.rst new file mode 100644 index 000000000..1d4427890 --- /dev/null +++ b/Documentation/fault-injection/nvme-fault-injection.rst @@ -0,0 +1,178 @@ +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_try_complete_req. 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 |