Documentation: nvme: Documentation for nvme fault injection
Add examples to show how to use nvme fault injection. Signed-off-by: Thomas Tai <thomas.tai@oracle.com> Reviewed-by: Eric Saint-Etienne <eric.saint.etienne@oracle.com> Signed-off-by: Karl Volz <karl.volz@oracle.com> Reviewed-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Thomas Tai
Jens Axboe
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cf4182f3d0
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@ -36,6 +36,14 @@ o fail_function
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ALLOW_ERROR_INJECTION() macro, by setting debugfs entries
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under /sys/kernel/debug/fail_function. No boot option supported.
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o NVMe fault injection
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inject NVMe status code and retry flag on devices permitted by setting
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debugfs entries under /sys/kernel/debug/nvme*/fault_inject. The default
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status code is NVME_SC_INVALID_OPCODE with no retry. The status code and
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retry flag can be set via the debugfs.
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Configure fault-injection capabilities behavior
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-----------------------------------------------
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@ -0,0 +1,116 @@
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NVMe Fault Injection
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====================
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Linux's fault injection framework provides a systematic way to support
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error injection via debugfs in the /sys/kernel/debug directory. When
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enabled, the default NVME_SC_INVALID_OPCODE with no retry will be
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injected into the nvme_end_request. Users can change the default status
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code and no retry flag via the debugfs. The list of Generic Command
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Status can be found in include/linux/nvme.h
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Following examples show how to inject an error into the nvme.
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First, enable CONFIG_FAULT_INJECTION_DEBUG_FS kernel config,
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recompile the kernel. After booting up the kernel, do the
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following.
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Example 1: Inject default status code with no retry
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---------------------------------------------------
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mount /dev/nvme0n1 /mnt
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echo 1 > /sys/kernel/debug/nvme0n1/fault_inject/times
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echo 100 > /sys/kernel/debug/nvme0n1/fault_inject/probability
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cp a.file /mnt
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Expected Result:
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cp: cannot stat ‘/mnt/a.file’: Input/output error
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Message from dmesg:
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FAULT_INJECTION: forcing a failure.
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name fault_inject, interval 1, probability 100, space 0, times 1
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CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.15.0-rc8+ #2
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Hardware name: innotek GmbH VirtualBox/VirtualBox,
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BIOS VirtualBox 12/01/2006
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Call Trace:
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<IRQ>
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dump_stack+0x5c/0x7d
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should_fail+0x148/0x170
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nvme_should_fail+0x2f/0x50 [nvme_core]
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nvme_process_cq+0xe7/0x1d0 [nvme]
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nvme_irq+0x1e/0x40 [nvme]
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__handle_irq_event_percpu+0x3a/0x190
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handle_irq_event_percpu+0x30/0x70
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handle_irq_event+0x36/0x60
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handle_fasteoi_irq+0x78/0x120
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handle_irq+0xa7/0x130
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? tick_irq_enter+0xa8/0xc0
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do_IRQ+0x43/0xc0
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common_interrupt+0xa2/0xa2
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</IRQ>
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RIP: 0010:native_safe_halt+0x2/0x10
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RSP: 0018:ffffffff82003e90 EFLAGS: 00000246 ORIG_RAX: ffffffffffffffdd
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RAX: ffffffff817a10c0 RBX: ffffffff82012480 RCX: 0000000000000000
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RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
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RBP: 0000000000000000 R08: 000000008e38ce64 R09: 0000000000000000
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R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff82012480
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R13: ffffffff82012480 R14: 0000000000000000 R15: 0000000000000000
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? __sched_text_end+0x4/0x4
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default_idle+0x18/0xf0
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do_idle+0x150/0x1d0
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cpu_startup_entry+0x6f/0x80
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start_kernel+0x4c4/0x4e4
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? set_init_arg+0x55/0x55
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secondary_startup_64+0xa5/0xb0
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print_req_error: I/O error, dev nvme0n1, sector 9240
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EXT4-fs error (device nvme0n1): ext4_find_entry:1436:
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inode #2: comm cp: reading directory lblock 0
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Example 2: Inject default status code with retry
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------------------------------------------------
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mount /dev/nvme0n1 /mnt
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echo 1 > /sys/kernel/debug/nvme0n1/fault_inject/times
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echo 100 > /sys/kernel/debug/nvme0n1/fault_inject/probability
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echo 1 > /sys/kernel/debug/nvme0n1/fault_inject/status
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echo 0 > /sys/kernel/debug/nvme0n1/fault_inject/dont_retry
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cp a.file /mnt
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Expected Result:
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command success without error
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Message from dmesg:
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FAULT_INJECTION: forcing a failure.
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name fault_inject, interval 1, probability 100, space 0, times 1
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CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.15.0-rc8+ #4
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Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
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Call Trace:
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<IRQ>
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dump_stack+0x5c/0x7d
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should_fail+0x148/0x170
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nvme_should_fail+0x30/0x60 [nvme_core]
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nvme_loop_queue_response+0x84/0x110 [nvme_loop]
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nvmet_req_complete+0x11/0x40 [nvmet]
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nvmet_bio_done+0x28/0x40 [nvmet]
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blk_update_request+0xb0/0x310
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blk_mq_end_request+0x18/0x60
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flush_smp_call_function_queue+0x3d/0xf0
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smp_call_function_single_interrupt+0x2c/0xc0
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call_function_single_interrupt+0xa2/0xb0
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</IRQ>
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RIP: 0010:native_safe_halt+0x2/0x10
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RSP: 0018:ffffc9000068bec0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff04
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RAX: ffffffff817a10c0 RBX: ffff88011a3c9680 RCX: 0000000000000000
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RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
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RBP: 0000000000000001 R08: 000000008e38c131 R09: 0000000000000000
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R10: 0000000000000000 R11: 0000000000000000 R12: ffff88011a3c9680
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R13: ffff88011a3c9680 R14: 0000000000000000 R15: 0000000000000000
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? __sched_text_end+0x4/0x4
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default_idle+0x18/0xf0
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do_idle+0x150/0x1d0
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cpu_startup_entry+0x6f/0x80
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start_secondary+0x187/0x1e0
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secondary_startup_64+0xa5/0xb0
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