From cf4182f3d06cec0546c69123f4104a2b69d07be2 Mon Sep 17 00:00:00 2001 From: Thomas Tai Date: Thu, 8 Feb 2018 13:38:30 -0500 Subject: Documentation: nvme: Documentation for nvme fault injection Add examples to show how to use nvme fault injection. Signed-off-by: Thomas Tai Reviewed-by: Eric Saint-Etienne Signed-off-by: Karl Volz Reviewed-by: Keith Busch Signed-off-by: Sagi Grimberg Signed-off-by: Jens Axboe --- Documentation/fault-injection/fault-injection.txt | 8 ++ .../fault-injection/nvme-fault-injection.txt | 116 +++++++++++++++++++++ 2 files changed, 124 insertions(+) create mode 100644 Documentation/fault-injection/nvme-fault-injection.txt diff --git a/Documentation/fault-injection/fault-injection.txt b/Documentation/fault-injection/fault-injection.txt index de1dc35fe500..4d1b7b4ccfaf 100644 --- a/Documentation/fault-injection/fault-injection.txt +++ b/Documentation/fault-injection/fault-injection.txt @@ -36,6 +36,14 @@ o fail_function ALLOW_ERROR_INJECTION() macro, by setting debugfs entries under /sys/kernel/debug/fail_function. No boot option supported. +o 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 + status code is NVME_SC_INVALID_OPCODE with no retry. The status code and + retry flag can be set via the debugfs. + + Configure fault-injection capabilities behavior ----------------------------------------------- diff --git a/Documentation/fault-injection/nvme-fault-injection.txt b/Documentation/fault-injection/nvme-fault-injection.txt new file mode 100644 index 000000000000..8fbf3bf60b62 --- /dev/null +++ b/Documentation/fault-injection/nvme-fault-injection.txt @@ -0,0 +1,116 @@ +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: + + 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 + +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: + + 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 + +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 -- cgit v1.2.3