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