110ffebbeSMauro Carvalho Chehab=========================================== 210ffebbeSMauro Carvalho ChehabFault injection capabilities infrastructure 310ffebbeSMauro Carvalho Chehab=========================================== 410ffebbeSMauro Carvalho Chehab 510ffebbeSMauro Carvalho ChehabSee also drivers/md/md-faulty.c and "every_nth" module option for scsi_debug. 610ffebbeSMauro Carvalho Chehab 710ffebbeSMauro Carvalho Chehab 810ffebbeSMauro Carvalho ChehabAvailable fault injection capabilities 910ffebbeSMauro Carvalho Chehab-------------------------------------- 1010ffebbeSMauro Carvalho Chehab 1110ffebbeSMauro Carvalho Chehab- failslab 1210ffebbeSMauro Carvalho Chehab 1310ffebbeSMauro Carvalho Chehab injects slab allocation failures. (kmalloc(), kmem_cache_alloc(), ...) 1410ffebbeSMauro Carvalho Chehab 1510ffebbeSMauro Carvalho Chehab- fail_page_alloc 1610ffebbeSMauro Carvalho Chehab 1710ffebbeSMauro Carvalho Chehab injects page allocation failures. (alloc_pages(), get_free_pages(), ...) 1810ffebbeSMauro Carvalho Chehab 1910ffebbeSMauro Carvalho Chehab- fail_futex 2010ffebbeSMauro Carvalho Chehab 2110ffebbeSMauro Carvalho Chehab injects futex deadlock and uaddr fault errors. 2210ffebbeSMauro Carvalho Chehab 2310ffebbeSMauro Carvalho Chehab- fail_make_request 2410ffebbeSMauro Carvalho Chehab 2510ffebbeSMauro Carvalho Chehab injects disk IO errors on devices permitted by setting 2610ffebbeSMauro Carvalho Chehab /sys/block/<device>/make-it-fail or 27*ed00aabdSChristoph Hellwig /sys/block/<device>/<partition>/make-it-fail. (submit_bio_noacct()) 2810ffebbeSMauro Carvalho Chehab 2910ffebbeSMauro Carvalho Chehab- fail_mmc_request 3010ffebbeSMauro Carvalho Chehab 3110ffebbeSMauro Carvalho Chehab injects MMC data errors on devices permitted by setting 3210ffebbeSMauro Carvalho Chehab debugfs entries under /sys/kernel/debug/mmc0/fail_mmc_request 3310ffebbeSMauro Carvalho Chehab 3410ffebbeSMauro Carvalho Chehab- fail_function 3510ffebbeSMauro Carvalho Chehab 3610ffebbeSMauro Carvalho Chehab injects error return on specific functions, which are marked by 3710ffebbeSMauro Carvalho Chehab ALLOW_ERROR_INJECTION() macro, by setting debugfs entries 3810ffebbeSMauro Carvalho Chehab under /sys/kernel/debug/fail_function. No boot option supported. 3910ffebbeSMauro Carvalho Chehab 4010ffebbeSMauro Carvalho Chehab- NVMe fault injection 4110ffebbeSMauro Carvalho Chehab 4210ffebbeSMauro Carvalho Chehab inject NVMe status code and retry flag on devices permitted by setting 4310ffebbeSMauro Carvalho Chehab debugfs entries under /sys/kernel/debug/nvme*/fault_inject. The default 4410ffebbeSMauro Carvalho Chehab status code is NVME_SC_INVALID_OPCODE with no retry. The status code and 4510ffebbeSMauro Carvalho Chehab retry flag can be set via the debugfs. 4610ffebbeSMauro Carvalho Chehab 4710ffebbeSMauro Carvalho Chehab 4810ffebbeSMauro Carvalho ChehabConfigure fault-injection capabilities behavior 4910ffebbeSMauro Carvalho Chehab----------------------------------------------- 5010ffebbeSMauro Carvalho Chehab 5110ffebbeSMauro Carvalho Chehabdebugfs entries 5210ffebbeSMauro Carvalho Chehab^^^^^^^^^^^^^^^ 5310ffebbeSMauro Carvalho Chehab 5410ffebbeSMauro Carvalho Chehabfault-inject-debugfs kernel module provides some debugfs entries for runtime 5510ffebbeSMauro Carvalho Chehabconfiguration of fault-injection capabilities. 5610ffebbeSMauro Carvalho Chehab 5710ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail*/probability: 5810ffebbeSMauro Carvalho Chehab 5910ffebbeSMauro Carvalho Chehab likelihood of failure injection, in percent. 6010ffebbeSMauro Carvalho Chehab 6110ffebbeSMauro Carvalho Chehab Format: <percent> 6210ffebbeSMauro Carvalho Chehab 6310ffebbeSMauro Carvalho Chehab Note that one-failure-per-hundred is a very high error rate 6410ffebbeSMauro Carvalho Chehab for some testcases. Consider setting probability=100 and configure 6510ffebbeSMauro Carvalho Chehab /sys/kernel/debug/fail*/interval for such testcases. 6610ffebbeSMauro Carvalho Chehab 6710ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail*/interval: 6810ffebbeSMauro Carvalho Chehab 6910ffebbeSMauro Carvalho Chehab specifies the interval between failures, for calls to 7010ffebbeSMauro Carvalho Chehab should_fail() that pass all the other tests. 7110ffebbeSMauro Carvalho Chehab 7210ffebbeSMauro Carvalho Chehab Note that if you enable this, by setting interval>1, you will 7310ffebbeSMauro Carvalho Chehab probably want to set probability=100. 7410ffebbeSMauro Carvalho Chehab 7510ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail*/times: 7610ffebbeSMauro Carvalho Chehab 7710ffebbeSMauro Carvalho Chehab specifies how many times failures may happen at most. 7810ffebbeSMauro Carvalho Chehab A value of -1 means "no limit". 7910ffebbeSMauro Carvalho Chehab 8010ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail*/space: 8110ffebbeSMauro Carvalho Chehab 8210ffebbeSMauro Carvalho Chehab specifies an initial resource "budget", decremented by "size" 8310ffebbeSMauro Carvalho Chehab on each call to should_fail(,size). Failure injection is 8410ffebbeSMauro Carvalho Chehab suppressed until "space" reaches zero. 8510ffebbeSMauro Carvalho Chehab 8610ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail*/verbose 8710ffebbeSMauro Carvalho Chehab 8810ffebbeSMauro Carvalho Chehab Format: { 0 | 1 | 2 } 8910ffebbeSMauro Carvalho Chehab 9010ffebbeSMauro Carvalho Chehab specifies the verbosity of the messages when failure is 9110ffebbeSMauro Carvalho Chehab injected. '0' means no messages; '1' will print only a single 9210ffebbeSMauro Carvalho Chehab log line per failure; '2' will print a call trace too -- useful 9310ffebbeSMauro Carvalho Chehab to debug the problems revealed by fault injection. 9410ffebbeSMauro Carvalho Chehab 9510ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail*/task-filter: 9610ffebbeSMauro Carvalho Chehab 9710ffebbeSMauro Carvalho Chehab Format: { 'Y' | 'N' } 9810ffebbeSMauro Carvalho Chehab 9910ffebbeSMauro Carvalho Chehab A value of 'N' disables filtering by process (default). 10010ffebbeSMauro Carvalho Chehab Any positive value limits failures to only processes indicated by 10110ffebbeSMauro Carvalho Chehab /proc/<pid>/make-it-fail==1. 10210ffebbeSMauro Carvalho Chehab 10310ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail*/require-start, 10410ffebbeSMauro Carvalho Chehab /sys/kernel/debug/fail*/require-end, 10510ffebbeSMauro Carvalho Chehab /sys/kernel/debug/fail*/reject-start, 10610ffebbeSMauro Carvalho Chehab /sys/kernel/debug/fail*/reject-end: 10710ffebbeSMauro Carvalho Chehab 10810ffebbeSMauro Carvalho Chehab specifies the range of virtual addresses tested during 10910ffebbeSMauro Carvalho Chehab stacktrace walking. Failure is injected only if some caller 11010ffebbeSMauro Carvalho Chehab in the walked stacktrace lies within the required range, and 11110ffebbeSMauro Carvalho Chehab none lies within the rejected range. 11210ffebbeSMauro Carvalho Chehab Default required range is [0,ULONG_MAX) (whole of virtual address space). 11310ffebbeSMauro Carvalho Chehab Default rejected range is [0,0). 11410ffebbeSMauro Carvalho Chehab 11510ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail*/stacktrace-depth: 11610ffebbeSMauro Carvalho Chehab 11710ffebbeSMauro Carvalho Chehab specifies the maximum stacktrace depth walked during search 11810ffebbeSMauro Carvalho Chehab for a caller within [require-start,require-end) OR 11910ffebbeSMauro Carvalho Chehab [reject-start,reject-end). 12010ffebbeSMauro Carvalho Chehab 12110ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail_page_alloc/ignore-gfp-highmem: 12210ffebbeSMauro Carvalho Chehab 12310ffebbeSMauro Carvalho Chehab Format: { 'Y' | 'N' } 12410ffebbeSMauro Carvalho Chehab 12510ffebbeSMauro Carvalho Chehab default is 'N', setting it to 'Y' won't inject failures into 12610ffebbeSMauro Carvalho Chehab highmem/user allocations. 12710ffebbeSMauro Carvalho Chehab 12810ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/failslab/ignore-gfp-wait: 12910ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail_page_alloc/ignore-gfp-wait: 13010ffebbeSMauro Carvalho Chehab 13110ffebbeSMauro Carvalho Chehab Format: { 'Y' | 'N' } 13210ffebbeSMauro Carvalho Chehab 13310ffebbeSMauro Carvalho Chehab default is 'N', setting it to 'Y' will inject failures 13410ffebbeSMauro Carvalho Chehab only into non-sleep allocations (GFP_ATOMIC allocations). 13510ffebbeSMauro Carvalho Chehab 13610ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail_page_alloc/min-order: 13710ffebbeSMauro Carvalho Chehab 13810ffebbeSMauro Carvalho Chehab specifies the minimum page allocation order to be injected 13910ffebbeSMauro Carvalho Chehab failures. 14010ffebbeSMauro Carvalho Chehab 14110ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail_futex/ignore-private: 14210ffebbeSMauro Carvalho Chehab 14310ffebbeSMauro Carvalho Chehab Format: { 'Y' | 'N' } 14410ffebbeSMauro Carvalho Chehab 14510ffebbeSMauro Carvalho Chehab default is 'N', setting it to 'Y' will disable failure injections 14610ffebbeSMauro Carvalho Chehab when dealing with private (address space) futexes. 14710ffebbeSMauro Carvalho Chehab 14810ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail_function/inject: 14910ffebbeSMauro Carvalho Chehab 15010ffebbeSMauro Carvalho Chehab Format: { 'function-name' | '!function-name' | '' } 15110ffebbeSMauro Carvalho Chehab 15210ffebbeSMauro Carvalho Chehab specifies the target function of error injection by name. 15310ffebbeSMauro Carvalho Chehab If the function name leads '!' prefix, given function is 15410ffebbeSMauro Carvalho Chehab removed from injection list. If nothing specified ('') 15510ffebbeSMauro Carvalho Chehab injection list is cleared. 15610ffebbeSMauro Carvalho Chehab 15710ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail_function/injectable: 15810ffebbeSMauro Carvalho Chehab 15910ffebbeSMauro Carvalho Chehab (read only) shows error injectable functions and what type of 16010ffebbeSMauro Carvalho Chehab error values can be specified. The error type will be one of 16110ffebbeSMauro Carvalho Chehab below; 16210ffebbeSMauro Carvalho Chehab - NULL: retval must be 0. 16310ffebbeSMauro Carvalho Chehab - ERRNO: retval must be -1 to -MAX_ERRNO (-4096). 16410ffebbeSMauro Carvalho Chehab - ERR_NULL: retval must be 0 or -1 to -MAX_ERRNO (-4096). 16510ffebbeSMauro Carvalho Chehab 16610ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail_function/<functiuon-name>/retval: 16710ffebbeSMauro Carvalho Chehab 16810ffebbeSMauro Carvalho Chehab specifies the "error" return value to inject to the given 16910ffebbeSMauro Carvalho Chehab function for given function. This will be created when 17010ffebbeSMauro Carvalho Chehab user specifies new injection entry. 17110ffebbeSMauro Carvalho Chehab 17210ffebbeSMauro Carvalho ChehabBoot option 17310ffebbeSMauro Carvalho Chehab^^^^^^^^^^^ 17410ffebbeSMauro Carvalho Chehab 17510ffebbeSMauro Carvalho ChehabIn order to inject faults while debugfs is not available (early boot time), 17610ffebbeSMauro Carvalho Chehabuse the boot option:: 17710ffebbeSMauro Carvalho Chehab 17810ffebbeSMauro Carvalho Chehab failslab= 17910ffebbeSMauro Carvalho Chehab fail_page_alloc= 18010ffebbeSMauro Carvalho Chehab fail_make_request= 18110ffebbeSMauro Carvalho Chehab fail_futex= 18210ffebbeSMauro Carvalho Chehab mmc_core.fail_request=<interval>,<probability>,<space>,<times> 18310ffebbeSMauro Carvalho Chehab 18410ffebbeSMauro Carvalho Chehabproc entries 18510ffebbeSMauro Carvalho Chehab^^^^^^^^^^^^ 18610ffebbeSMauro Carvalho Chehab 18710ffebbeSMauro Carvalho Chehab- /proc/<pid>/fail-nth, 18810ffebbeSMauro Carvalho Chehab /proc/self/task/<tid>/fail-nth: 18910ffebbeSMauro Carvalho Chehab 19010ffebbeSMauro Carvalho Chehab Write to this file of integer N makes N-th call in the task fail. 19110ffebbeSMauro Carvalho Chehab Read from this file returns a integer value. A value of '0' indicates 19210ffebbeSMauro Carvalho Chehab that the fault setup with a previous write to this file was injected. 19310ffebbeSMauro Carvalho Chehab A positive integer N indicates that the fault wasn't yet injected. 19410ffebbeSMauro Carvalho Chehab Note that this file enables all types of faults (slab, futex, etc). 19510ffebbeSMauro Carvalho Chehab This setting takes precedence over all other generic debugfs settings 19610ffebbeSMauro Carvalho Chehab like probability, interval, times, etc. But per-capability settings 19710ffebbeSMauro Carvalho Chehab (e.g. fail_futex/ignore-private) take precedence over it. 19810ffebbeSMauro Carvalho Chehab 19910ffebbeSMauro Carvalho Chehab This feature is intended for systematic testing of faults in a single 20010ffebbeSMauro Carvalho Chehab system call. See an example below. 20110ffebbeSMauro Carvalho Chehab 20210ffebbeSMauro Carvalho ChehabHow to add new fault injection capability 20310ffebbeSMauro Carvalho Chehab----------------------------------------- 20410ffebbeSMauro Carvalho Chehab 20510ffebbeSMauro Carvalho Chehab- #include <linux/fault-inject.h> 20610ffebbeSMauro Carvalho Chehab 20710ffebbeSMauro Carvalho Chehab- define the fault attributes 20810ffebbeSMauro Carvalho Chehab 20910ffebbeSMauro Carvalho Chehab DECLARE_FAULT_ATTR(name); 21010ffebbeSMauro Carvalho Chehab 21110ffebbeSMauro Carvalho Chehab Please see the definition of struct fault_attr in fault-inject.h 21210ffebbeSMauro Carvalho Chehab for details. 21310ffebbeSMauro Carvalho Chehab 21410ffebbeSMauro Carvalho Chehab- provide a way to configure fault attributes 21510ffebbeSMauro Carvalho Chehab 21610ffebbeSMauro Carvalho Chehab- boot option 21710ffebbeSMauro Carvalho Chehab 21810ffebbeSMauro Carvalho Chehab If you need to enable the fault injection capability from boot time, you can 21910ffebbeSMauro Carvalho Chehab provide boot option to configure it. There is a helper function for it: 22010ffebbeSMauro Carvalho Chehab 22110ffebbeSMauro Carvalho Chehab setup_fault_attr(attr, str); 22210ffebbeSMauro Carvalho Chehab 22310ffebbeSMauro Carvalho Chehab- debugfs entries 22410ffebbeSMauro Carvalho Chehab 22510ffebbeSMauro Carvalho Chehab failslab, fail_page_alloc, and fail_make_request use this way. 22610ffebbeSMauro Carvalho Chehab Helper functions: 22710ffebbeSMauro Carvalho Chehab 22810ffebbeSMauro Carvalho Chehab fault_create_debugfs_attr(name, parent, attr); 22910ffebbeSMauro Carvalho Chehab 23010ffebbeSMauro Carvalho Chehab- module parameters 23110ffebbeSMauro Carvalho Chehab 23210ffebbeSMauro Carvalho Chehab If the scope of the fault injection capability is limited to a 23310ffebbeSMauro Carvalho Chehab single kernel module, it is better to provide module parameters to 23410ffebbeSMauro Carvalho Chehab configure the fault attributes. 23510ffebbeSMauro Carvalho Chehab 23610ffebbeSMauro Carvalho Chehab- add a hook to insert failures 23710ffebbeSMauro Carvalho Chehab 23810ffebbeSMauro Carvalho Chehab Upon should_fail() returning true, client code should inject a failure: 23910ffebbeSMauro Carvalho Chehab 24010ffebbeSMauro Carvalho Chehab should_fail(attr, size); 24110ffebbeSMauro Carvalho Chehab 24210ffebbeSMauro Carvalho ChehabApplication Examples 24310ffebbeSMauro Carvalho Chehab-------------------- 24410ffebbeSMauro Carvalho Chehab 24510ffebbeSMauro Carvalho Chehab- Inject slab allocation failures into module init/exit code:: 24610ffebbeSMauro Carvalho Chehab 24710ffebbeSMauro Carvalho Chehab #!/bin/bash 24810ffebbeSMauro Carvalho Chehab 24910ffebbeSMauro Carvalho Chehab FAILTYPE=failslab 25010ffebbeSMauro Carvalho Chehab echo Y > /sys/kernel/debug/$FAILTYPE/task-filter 25110ffebbeSMauro Carvalho Chehab echo 10 > /sys/kernel/debug/$FAILTYPE/probability 25210ffebbeSMauro Carvalho Chehab echo 100 > /sys/kernel/debug/$FAILTYPE/interval 25310ffebbeSMauro Carvalho Chehab echo -1 > /sys/kernel/debug/$FAILTYPE/times 25410ffebbeSMauro Carvalho Chehab echo 0 > /sys/kernel/debug/$FAILTYPE/space 25510ffebbeSMauro Carvalho Chehab echo 2 > /sys/kernel/debug/$FAILTYPE/verbose 25610ffebbeSMauro Carvalho Chehab echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-wait 25710ffebbeSMauro Carvalho Chehab 25810ffebbeSMauro Carvalho Chehab faulty_system() 25910ffebbeSMauro Carvalho Chehab { 26010ffebbeSMauro Carvalho Chehab bash -c "echo 1 > /proc/self/make-it-fail && exec $*" 26110ffebbeSMauro Carvalho Chehab } 26210ffebbeSMauro Carvalho Chehab 26310ffebbeSMauro Carvalho Chehab if [ $# -eq 0 ] 26410ffebbeSMauro Carvalho Chehab then 26510ffebbeSMauro Carvalho Chehab echo "Usage: $0 modulename [ modulename ... ]" 26610ffebbeSMauro Carvalho Chehab exit 1 26710ffebbeSMauro Carvalho Chehab fi 26810ffebbeSMauro Carvalho Chehab 26910ffebbeSMauro Carvalho Chehab for m in $* 27010ffebbeSMauro Carvalho Chehab do 27110ffebbeSMauro Carvalho Chehab echo inserting $m... 27210ffebbeSMauro Carvalho Chehab faulty_system modprobe $m 27310ffebbeSMauro Carvalho Chehab 27410ffebbeSMauro Carvalho Chehab echo removing $m... 27510ffebbeSMauro Carvalho Chehab faulty_system modprobe -r $m 27610ffebbeSMauro Carvalho Chehab done 27710ffebbeSMauro Carvalho Chehab 27810ffebbeSMauro Carvalho Chehab------------------------------------------------------------------------------ 27910ffebbeSMauro Carvalho Chehab 28010ffebbeSMauro Carvalho Chehab- Inject page allocation failures only for a specific module:: 28110ffebbeSMauro Carvalho Chehab 28210ffebbeSMauro Carvalho Chehab #!/bin/bash 28310ffebbeSMauro Carvalho Chehab 28410ffebbeSMauro Carvalho Chehab FAILTYPE=fail_page_alloc 28510ffebbeSMauro Carvalho Chehab module=$1 28610ffebbeSMauro Carvalho Chehab 28710ffebbeSMauro Carvalho Chehab if [ -z $module ] 28810ffebbeSMauro Carvalho Chehab then 28910ffebbeSMauro Carvalho Chehab echo "Usage: $0 <modulename>" 29010ffebbeSMauro Carvalho Chehab exit 1 29110ffebbeSMauro Carvalho Chehab fi 29210ffebbeSMauro Carvalho Chehab 29310ffebbeSMauro Carvalho Chehab modprobe $module 29410ffebbeSMauro Carvalho Chehab 29510ffebbeSMauro Carvalho Chehab if [ ! -d /sys/module/$module/sections ] 29610ffebbeSMauro Carvalho Chehab then 29710ffebbeSMauro Carvalho Chehab echo Module $module is not loaded 29810ffebbeSMauro Carvalho Chehab exit 1 29910ffebbeSMauro Carvalho Chehab fi 30010ffebbeSMauro Carvalho Chehab 30110ffebbeSMauro Carvalho Chehab cat /sys/module/$module/sections/.text > /sys/kernel/debug/$FAILTYPE/require-start 30210ffebbeSMauro Carvalho Chehab cat /sys/module/$module/sections/.data > /sys/kernel/debug/$FAILTYPE/require-end 30310ffebbeSMauro Carvalho Chehab 30410ffebbeSMauro Carvalho Chehab echo N > /sys/kernel/debug/$FAILTYPE/task-filter 30510ffebbeSMauro Carvalho Chehab echo 10 > /sys/kernel/debug/$FAILTYPE/probability 30610ffebbeSMauro Carvalho Chehab echo 100 > /sys/kernel/debug/$FAILTYPE/interval 30710ffebbeSMauro Carvalho Chehab echo -1 > /sys/kernel/debug/$FAILTYPE/times 30810ffebbeSMauro Carvalho Chehab echo 0 > /sys/kernel/debug/$FAILTYPE/space 30910ffebbeSMauro Carvalho Chehab echo 2 > /sys/kernel/debug/$FAILTYPE/verbose 31010ffebbeSMauro Carvalho Chehab echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-wait 31110ffebbeSMauro Carvalho Chehab echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-highmem 31210ffebbeSMauro Carvalho Chehab echo 10 > /sys/kernel/debug/$FAILTYPE/stacktrace-depth 31310ffebbeSMauro Carvalho Chehab 31410ffebbeSMauro Carvalho Chehab trap "echo 0 > /sys/kernel/debug/$FAILTYPE/probability" SIGINT SIGTERM EXIT 31510ffebbeSMauro Carvalho Chehab 31610ffebbeSMauro Carvalho Chehab echo "Injecting errors into the module $module... (interrupt to stop)" 31710ffebbeSMauro Carvalho Chehab sleep 1000000 31810ffebbeSMauro Carvalho Chehab 31910ffebbeSMauro Carvalho Chehab------------------------------------------------------------------------------ 32010ffebbeSMauro Carvalho Chehab 32110ffebbeSMauro Carvalho Chehab- Inject open_ctree error while btrfs mount:: 32210ffebbeSMauro Carvalho Chehab 32310ffebbeSMauro Carvalho Chehab #!/bin/bash 32410ffebbeSMauro Carvalho Chehab 32510ffebbeSMauro Carvalho Chehab rm -f testfile.img 32610ffebbeSMauro Carvalho Chehab dd if=/dev/zero of=testfile.img bs=1M seek=1000 count=1 32710ffebbeSMauro Carvalho Chehab DEVICE=$(losetup --show -f testfile.img) 32810ffebbeSMauro Carvalho Chehab mkfs.btrfs -f $DEVICE 32910ffebbeSMauro Carvalho Chehab mkdir -p tmpmnt 33010ffebbeSMauro Carvalho Chehab 33110ffebbeSMauro Carvalho Chehab FAILTYPE=fail_function 33210ffebbeSMauro Carvalho Chehab FAILFUNC=open_ctree 33310ffebbeSMauro Carvalho Chehab echo $FAILFUNC > /sys/kernel/debug/$FAILTYPE/inject 33410ffebbeSMauro Carvalho Chehab echo -12 > /sys/kernel/debug/$FAILTYPE/$FAILFUNC/retval 33510ffebbeSMauro Carvalho Chehab echo N > /sys/kernel/debug/$FAILTYPE/task-filter 33610ffebbeSMauro Carvalho Chehab echo 100 > /sys/kernel/debug/$FAILTYPE/probability 33710ffebbeSMauro Carvalho Chehab echo 0 > /sys/kernel/debug/$FAILTYPE/interval 33810ffebbeSMauro Carvalho Chehab echo -1 > /sys/kernel/debug/$FAILTYPE/times 33910ffebbeSMauro Carvalho Chehab echo 0 > /sys/kernel/debug/$FAILTYPE/space 34010ffebbeSMauro Carvalho Chehab echo 1 > /sys/kernel/debug/$FAILTYPE/verbose 34110ffebbeSMauro Carvalho Chehab 34210ffebbeSMauro Carvalho Chehab mount -t btrfs $DEVICE tmpmnt 34310ffebbeSMauro Carvalho Chehab if [ $? -ne 0 ] 34410ffebbeSMauro Carvalho Chehab then 34510ffebbeSMauro Carvalho Chehab echo "SUCCESS!" 34610ffebbeSMauro Carvalho Chehab else 34710ffebbeSMauro Carvalho Chehab echo "FAILED!" 34810ffebbeSMauro Carvalho Chehab umount tmpmnt 34910ffebbeSMauro Carvalho Chehab fi 35010ffebbeSMauro Carvalho Chehab 35110ffebbeSMauro Carvalho Chehab echo > /sys/kernel/debug/$FAILTYPE/inject 35210ffebbeSMauro Carvalho Chehab 35310ffebbeSMauro Carvalho Chehab rmdir tmpmnt 35410ffebbeSMauro Carvalho Chehab losetup -d $DEVICE 35510ffebbeSMauro Carvalho Chehab rm testfile.img 35610ffebbeSMauro Carvalho Chehab 35710ffebbeSMauro Carvalho Chehab 35810ffebbeSMauro Carvalho ChehabTool to run command with failslab or fail_page_alloc 35910ffebbeSMauro Carvalho Chehab---------------------------------------------------- 36010ffebbeSMauro Carvalho ChehabIn order to make it easier to accomplish the tasks mentioned above, we can use 36110ffebbeSMauro Carvalho Chehabtools/testing/fault-injection/failcmd.sh. Please run a command 36210ffebbeSMauro Carvalho Chehab"./tools/testing/fault-injection/failcmd.sh --help" for more information and 36310ffebbeSMauro Carvalho Chehabsee the following examples. 36410ffebbeSMauro Carvalho Chehab 36510ffebbeSMauro Carvalho ChehabExamples: 36610ffebbeSMauro Carvalho Chehab 36710ffebbeSMauro Carvalho ChehabRun a command "make -C tools/testing/selftests/ run_tests" with injecting slab 36810ffebbeSMauro Carvalho Chehaballocation failure:: 36910ffebbeSMauro Carvalho Chehab 37010ffebbeSMauro Carvalho Chehab # ./tools/testing/fault-injection/failcmd.sh \ 37110ffebbeSMauro Carvalho Chehab -- make -C tools/testing/selftests/ run_tests 37210ffebbeSMauro Carvalho Chehab 37310ffebbeSMauro Carvalho ChehabSame as above except to specify 100 times failures at most instead of one time 37410ffebbeSMauro Carvalho Chehabat most by default:: 37510ffebbeSMauro Carvalho Chehab 37610ffebbeSMauro Carvalho Chehab # ./tools/testing/fault-injection/failcmd.sh --times=100 \ 37710ffebbeSMauro Carvalho Chehab -- make -C tools/testing/selftests/ run_tests 37810ffebbeSMauro Carvalho Chehab 37910ffebbeSMauro Carvalho ChehabSame as above except to inject page allocation failure instead of slab 38010ffebbeSMauro Carvalho Chehaballocation failure:: 38110ffebbeSMauro Carvalho Chehab 38210ffebbeSMauro Carvalho Chehab # env FAILCMD_TYPE=fail_page_alloc \ 38310ffebbeSMauro Carvalho Chehab ./tools/testing/fault-injection/failcmd.sh --times=100 \ 38410ffebbeSMauro Carvalho Chehab -- make -C tools/testing/selftests/ run_tests 38510ffebbeSMauro Carvalho Chehab 38610ffebbeSMauro Carvalho ChehabSystematic faults using fail-nth 38710ffebbeSMauro Carvalho Chehab--------------------------------- 38810ffebbeSMauro Carvalho Chehab 38910ffebbeSMauro Carvalho ChehabThe following code systematically faults 0-th, 1-st, 2-nd and so on 39010ffebbeSMauro Carvalho Chehabcapabilities in the socketpair() system call:: 39110ffebbeSMauro Carvalho Chehab 39210ffebbeSMauro Carvalho Chehab #include <sys/types.h> 39310ffebbeSMauro Carvalho Chehab #include <sys/stat.h> 39410ffebbeSMauro Carvalho Chehab #include <sys/socket.h> 39510ffebbeSMauro Carvalho Chehab #include <sys/syscall.h> 39610ffebbeSMauro Carvalho Chehab #include <fcntl.h> 39710ffebbeSMauro Carvalho Chehab #include <unistd.h> 39810ffebbeSMauro Carvalho Chehab #include <string.h> 39910ffebbeSMauro Carvalho Chehab #include <stdlib.h> 40010ffebbeSMauro Carvalho Chehab #include <stdio.h> 40110ffebbeSMauro Carvalho Chehab #include <errno.h> 40210ffebbeSMauro Carvalho Chehab 40310ffebbeSMauro Carvalho Chehab int main() 40410ffebbeSMauro Carvalho Chehab { 40510ffebbeSMauro Carvalho Chehab int i, err, res, fail_nth, fds[2]; 40610ffebbeSMauro Carvalho Chehab char buf[128]; 40710ffebbeSMauro Carvalho Chehab 40810ffebbeSMauro Carvalho Chehab system("echo N > /sys/kernel/debug/failslab/ignore-gfp-wait"); 40910ffebbeSMauro Carvalho Chehab sprintf(buf, "/proc/self/task/%ld/fail-nth", syscall(SYS_gettid)); 41010ffebbeSMauro Carvalho Chehab fail_nth = open(buf, O_RDWR); 41110ffebbeSMauro Carvalho Chehab for (i = 1;; i++) { 41210ffebbeSMauro Carvalho Chehab sprintf(buf, "%d", i); 41310ffebbeSMauro Carvalho Chehab write(fail_nth, buf, strlen(buf)); 41410ffebbeSMauro Carvalho Chehab res = socketpair(AF_LOCAL, SOCK_STREAM, 0, fds); 41510ffebbeSMauro Carvalho Chehab err = errno; 41610ffebbeSMauro Carvalho Chehab pread(fail_nth, buf, sizeof(buf), 0); 41710ffebbeSMauro Carvalho Chehab if (res == 0) { 41810ffebbeSMauro Carvalho Chehab close(fds[0]); 41910ffebbeSMauro Carvalho Chehab close(fds[1]); 42010ffebbeSMauro Carvalho Chehab } 42110ffebbeSMauro Carvalho Chehab printf("%d-th fault %c: res=%d/%d\n", i, atoi(buf) ? 'N' : 'Y', 42210ffebbeSMauro Carvalho Chehab res, err); 42310ffebbeSMauro Carvalho Chehab if (atoi(buf)) 42410ffebbeSMauro Carvalho Chehab break; 42510ffebbeSMauro Carvalho Chehab } 42610ffebbeSMauro Carvalho Chehab return 0; 42710ffebbeSMauro Carvalho Chehab } 42810ffebbeSMauro Carvalho Chehab 42910ffebbeSMauro Carvalho ChehabAn example output:: 43010ffebbeSMauro Carvalho Chehab 43110ffebbeSMauro Carvalho Chehab 1-th fault Y: res=-1/23 43210ffebbeSMauro Carvalho Chehab 2-th fault Y: res=-1/23 43310ffebbeSMauro Carvalho Chehab 3-th fault Y: res=-1/12 43410ffebbeSMauro Carvalho Chehab 4-th fault Y: res=-1/12 43510ffebbeSMauro Carvalho Chehab 5-th fault Y: res=-1/23 43610ffebbeSMauro Carvalho Chehab 6-th fault Y: res=-1/23 43710ffebbeSMauro Carvalho Chehab 7-th fault Y: res=-1/23 43810ffebbeSMauro Carvalho Chehab 8-th fault Y: res=-1/12 43910ffebbeSMauro Carvalho Chehab 9-th fault Y: res=-1/12 44010ffebbeSMauro Carvalho Chehab 10-th fault Y: res=-1/12 44110ffebbeSMauro Carvalho Chehab 11-th fault Y: res=-1/12 44210ffebbeSMauro Carvalho Chehab 12-th fault Y: res=-1/12 44310ffebbeSMauro Carvalho Chehab 13-th fault Y: res=-1/12 44410ffebbeSMauro Carvalho Chehab 14-th fault Y: res=-1/12 44510ffebbeSMauro Carvalho Chehab 15-th fault Y: res=-1/12 44610ffebbeSMauro Carvalho Chehab 16-th fault N: res=0/12 447