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 19*2c739cedSAlbert van der Linde- fail_usercopy 20*2c739cedSAlbert van der Linde 21*2c739cedSAlbert van der Linde injects failures in user memory access functions. (copy_from_user(), get_user(), ...) 22*2c739cedSAlbert van der Linde 2310ffebbeSMauro Carvalho Chehab- fail_futex 2410ffebbeSMauro Carvalho Chehab 2510ffebbeSMauro Carvalho Chehab injects futex deadlock and uaddr fault errors. 2610ffebbeSMauro Carvalho Chehab 2710ffebbeSMauro Carvalho Chehab- fail_make_request 2810ffebbeSMauro Carvalho Chehab 2910ffebbeSMauro Carvalho Chehab injects disk IO errors on devices permitted by setting 3010ffebbeSMauro Carvalho Chehab /sys/block/<device>/make-it-fail or 31ed00aabdSChristoph Hellwig /sys/block/<device>/<partition>/make-it-fail. (submit_bio_noacct()) 3210ffebbeSMauro Carvalho Chehab 3310ffebbeSMauro Carvalho Chehab- fail_mmc_request 3410ffebbeSMauro Carvalho Chehab 3510ffebbeSMauro Carvalho Chehab injects MMC data errors on devices permitted by setting 3610ffebbeSMauro Carvalho Chehab debugfs entries under /sys/kernel/debug/mmc0/fail_mmc_request 3710ffebbeSMauro Carvalho Chehab 3810ffebbeSMauro Carvalho Chehab- fail_function 3910ffebbeSMauro Carvalho Chehab 4010ffebbeSMauro Carvalho Chehab injects error return on specific functions, which are marked by 4110ffebbeSMauro Carvalho Chehab ALLOW_ERROR_INJECTION() macro, by setting debugfs entries 4210ffebbeSMauro Carvalho Chehab under /sys/kernel/debug/fail_function. No boot option supported. 4310ffebbeSMauro Carvalho Chehab 4410ffebbeSMauro Carvalho Chehab- NVMe fault injection 4510ffebbeSMauro Carvalho Chehab 4610ffebbeSMauro Carvalho Chehab inject NVMe status code and retry flag on devices permitted by setting 4710ffebbeSMauro Carvalho Chehab debugfs entries under /sys/kernel/debug/nvme*/fault_inject. The default 4810ffebbeSMauro Carvalho Chehab status code is NVME_SC_INVALID_OPCODE with no retry. The status code and 4910ffebbeSMauro Carvalho Chehab retry flag can be set via the debugfs. 5010ffebbeSMauro Carvalho Chehab 5110ffebbeSMauro Carvalho Chehab 5210ffebbeSMauro Carvalho ChehabConfigure fault-injection capabilities behavior 5310ffebbeSMauro Carvalho Chehab----------------------------------------------- 5410ffebbeSMauro Carvalho Chehab 5510ffebbeSMauro Carvalho Chehabdebugfs entries 5610ffebbeSMauro Carvalho Chehab^^^^^^^^^^^^^^^ 5710ffebbeSMauro Carvalho Chehab 5810ffebbeSMauro Carvalho Chehabfault-inject-debugfs kernel module provides some debugfs entries for runtime 5910ffebbeSMauro Carvalho Chehabconfiguration of fault-injection capabilities. 6010ffebbeSMauro Carvalho Chehab 6110ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail*/probability: 6210ffebbeSMauro Carvalho Chehab 6310ffebbeSMauro Carvalho Chehab likelihood of failure injection, in percent. 6410ffebbeSMauro Carvalho Chehab 6510ffebbeSMauro Carvalho Chehab Format: <percent> 6610ffebbeSMauro Carvalho Chehab 6710ffebbeSMauro Carvalho Chehab Note that one-failure-per-hundred is a very high error rate 6810ffebbeSMauro Carvalho Chehab for some testcases. Consider setting probability=100 and configure 6910ffebbeSMauro Carvalho Chehab /sys/kernel/debug/fail*/interval for such testcases. 7010ffebbeSMauro Carvalho Chehab 7110ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail*/interval: 7210ffebbeSMauro Carvalho Chehab 7310ffebbeSMauro Carvalho Chehab specifies the interval between failures, for calls to 7410ffebbeSMauro Carvalho Chehab should_fail() that pass all the other tests. 7510ffebbeSMauro Carvalho Chehab 7610ffebbeSMauro Carvalho Chehab Note that if you enable this, by setting interval>1, you will 7710ffebbeSMauro Carvalho Chehab probably want to set probability=100. 7810ffebbeSMauro Carvalho Chehab 7910ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail*/times: 8010ffebbeSMauro Carvalho Chehab 8110ffebbeSMauro Carvalho Chehab specifies how many times failures may happen at most. 8210ffebbeSMauro Carvalho Chehab A value of -1 means "no limit". 8310ffebbeSMauro Carvalho Chehab 8410ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail*/space: 8510ffebbeSMauro Carvalho Chehab 8610ffebbeSMauro Carvalho Chehab specifies an initial resource "budget", decremented by "size" 8710ffebbeSMauro Carvalho Chehab on each call to should_fail(,size). Failure injection is 8810ffebbeSMauro Carvalho Chehab suppressed until "space" reaches zero. 8910ffebbeSMauro Carvalho Chehab 9010ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail*/verbose 9110ffebbeSMauro Carvalho Chehab 9210ffebbeSMauro Carvalho Chehab Format: { 0 | 1 | 2 } 9310ffebbeSMauro Carvalho Chehab 9410ffebbeSMauro Carvalho Chehab specifies the verbosity of the messages when failure is 9510ffebbeSMauro Carvalho Chehab injected. '0' means no messages; '1' will print only a single 9610ffebbeSMauro Carvalho Chehab log line per failure; '2' will print a call trace too -- useful 9710ffebbeSMauro Carvalho Chehab to debug the problems revealed by fault injection. 9810ffebbeSMauro Carvalho Chehab 9910ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail*/task-filter: 10010ffebbeSMauro Carvalho Chehab 10110ffebbeSMauro Carvalho Chehab Format: { 'Y' | 'N' } 10210ffebbeSMauro Carvalho Chehab 10310ffebbeSMauro Carvalho Chehab A value of 'N' disables filtering by process (default). 10410ffebbeSMauro Carvalho Chehab Any positive value limits failures to only processes indicated by 10510ffebbeSMauro Carvalho Chehab /proc/<pid>/make-it-fail==1. 10610ffebbeSMauro Carvalho Chehab 10710ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail*/require-start, 10810ffebbeSMauro Carvalho Chehab /sys/kernel/debug/fail*/require-end, 10910ffebbeSMauro Carvalho Chehab /sys/kernel/debug/fail*/reject-start, 11010ffebbeSMauro Carvalho Chehab /sys/kernel/debug/fail*/reject-end: 11110ffebbeSMauro Carvalho Chehab 11210ffebbeSMauro Carvalho Chehab specifies the range of virtual addresses tested during 11310ffebbeSMauro Carvalho Chehab stacktrace walking. Failure is injected only if some caller 11410ffebbeSMauro Carvalho Chehab in the walked stacktrace lies within the required range, and 11510ffebbeSMauro Carvalho Chehab none lies within the rejected range. 11610ffebbeSMauro Carvalho Chehab Default required range is [0,ULONG_MAX) (whole of virtual address space). 11710ffebbeSMauro Carvalho Chehab Default rejected range is [0,0). 11810ffebbeSMauro Carvalho Chehab 11910ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail*/stacktrace-depth: 12010ffebbeSMauro Carvalho Chehab 12110ffebbeSMauro Carvalho Chehab specifies the maximum stacktrace depth walked during search 12210ffebbeSMauro Carvalho Chehab for a caller within [require-start,require-end) OR 12310ffebbeSMauro Carvalho Chehab [reject-start,reject-end). 12410ffebbeSMauro Carvalho Chehab 12510ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail_page_alloc/ignore-gfp-highmem: 12610ffebbeSMauro Carvalho Chehab 12710ffebbeSMauro Carvalho Chehab Format: { 'Y' | 'N' } 12810ffebbeSMauro Carvalho Chehab 12910ffebbeSMauro Carvalho Chehab default is 'N', setting it to 'Y' won't inject failures into 13010ffebbeSMauro Carvalho Chehab highmem/user allocations. 13110ffebbeSMauro Carvalho Chehab 13210ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/failslab/ignore-gfp-wait: 13310ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail_page_alloc/ignore-gfp-wait: 13410ffebbeSMauro Carvalho Chehab 13510ffebbeSMauro Carvalho Chehab Format: { 'Y' | 'N' } 13610ffebbeSMauro Carvalho Chehab 13710ffebbeSMauro Carvalho Chehab default is 'N', setting it to 'Y' will inject failures 13810ffebbeSMauro Carvalho Chehab only into non-sleep allocations (GFP_ATOMIC allocations). 13910ffebbeSMauro Carvalho Chehab 14010ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail_page_alloc/min-order: 14110ffebbeSMauro Carvalho Chehab 14210ffebbeSMauro Carvalho Chehab specifies the minimum page allocation order to be injected 14310ffebbeSMauro Carvalho Chehab failures. 14410ffebbeSMauro Carvalho Chehab 14510ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail_futex/ignore-private: 14610ffebbeSMauro Carvalho Chehab 14710ffebbeSMauro Carvalho Chehab Format: { 'Y' | 'N' } 14810ffebbeSMauro Carvalho Chehab 14910ffebbeSMauro Carvalho Chehab default is 'N', setting it to 'Y' will disable failure injections 15010ffebbeSMauro Carvalho Chehab when dealing with private (address space) futexes. 15110ffebbeSMauro Carvalho Chehab 15210ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail_function/inject: 15310ffebbeSMauro Carvalho Chehab 15410ffebbeSMauro Carvalho Chehab Format: { 'function-name' | '!function-name' | '' } 15510ffebbeSMauro Carvalho Chehab 15610ffebbeSMauro Carvalho Chehab specifies the target function of error injection by name. 15710ffebbeSMauro Carvalho Chehab If the function name leads '!' prefix, given function is 15810ffebbeSMauro Carvalho Chehab removed from injection list. If nothing specified ('') 15910ffebbeSMauro Carvalho Chehab injection list is cleared. 16010ffebbeSMauro Carvalho Chehab 16110ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail_function/injectable: 16210ffebbeSMauro Carvalho Chehab 16310ffebbeSMauro Carvalho Chehab (read only) shows error injectable functions and what type of 16410ffebbeSMauro Carvalho Chehab error values can be specified. The error type will be one of 16510ffebbeSMauro Carvalho Chehab below; 16610ffebbeSMauro Carvalho Chehab - NULL: retval must be 0. 16710ffebbeSMauro Carvalho Chehab - ERRNO: retval must be -1 to -MAX_ERRNO (-4096). 16810ffebbeSMauro Carvalho Chehab - ERR_NULL: retval must be 0 or -1 to -MAX_ERRNO (-4096). 16910ffebbeSMauro Carvalho Chehab 17010ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail_function/<functiuon-name>/retval: 17110ffebbeSMauro Carvalho Chehab 17210ffebbeSMauro Carvalho Chehab specifies the "error" return value to inject to the given 17310ffebbeSMauro Carvalho Chehab function for given function. This will be created when 17410ffebbeSMauro Carvalho Chehab user specifies new injection entry. 17510ffebbeSMauro Carvalho Chehab 17610ffebbeSMauro Carvalho ChehabBoot option 17710ffebbeSMauro Carvalho Chehab^^^^^^^^^^^ 17810ffebbeSMauro Carvalho Chehab 17910ffebbeSMauro Carvalho ChehabIn order to inject faults while debugfs is not available (early boot time), 18010ffebbeSMauro Carvalho Chehabuse the boot option:: 18110ffebbeSMauro Carvalho Chehab 18210ffebbeSMauro Carvalho Chehab failslab= 18310ffebbeSMauro Carvalho Chehab fail_page_alloc= 184*2c739cedSAlbert van der Linde fail_usercopy= 18510ffebbeSMauro Carvalho Chehab fail_make_request= 18610ffebbeSMauro Carvalho Chehab fail_futex= 18710ffebbeSMauro Carvalho Chehab mmc_core.fail_request=<interval>,<probability>,<space>,<times> 18810ffebbeSMauro Carvalho Chehab 18910ffebbeSMauro Carvalho Chehabproc entries 19010ffebbeSMauro Carvalho Chehab^^^^^^^^^^^^ 19110ffebbeSMauro Carvalho Chehab 19210ffebbeSMauro Carvalho Chehab- /proc/<pid>/fail-nth, 19310ffebbeSMauro Carvalho Chehab /proc/self/task/<tid>/fail-nth: 19410ffebbeSMauro Carvalho Chehab 19510ffebbeSMauro Carvalho Chehab Write to this file of integer N makes N-th call in the task fail. 19610ffebbeSMauro Carvalho Chehab Read from this file returns a integer value. A value of '0' indicates 19710ffebbeSMauro Carvalho Chehab that the fault setup with a previous write to this file was injected. 19810ffebbeSMauro Carvalho Chehab A positive integer N indicates that the fault wasn't yet injected. 19910ffebbeSMauro Carvalho Chehab Note that this file enables all types of faults (slab, futex, etc). 20010ffebbeSMauro Carvalho Chehab This setting takes precedence over all other generic debugfs settings 20110ffebbeSMauro Carvalho Chehab like probability, interval, times, etc. But per-capability settings 20210ffebbeSMauro Carvalho Chehab (e.g. fail_futex/ignore-private) take precedence over it. 20310ffebbeSMauro Carvalho Chehab 20410ffebbeSMauro Carvalho Chehab This feature is intended for systematic testing of faults in a single 20510ffebbeSMauro Carvalho Chehab system call. See an example below. 20610ffebbeSMauro Carvalho Chehab 20710ffebbeSMauro Carvalho ChehabHow to add new fault injection capability 20810ffebbeSMauro Carvalho Chehab----------------------------------------- 20910ffebbeSMauro Carvalho Chehab 21010ffebbeSMauro Carvalho Chehab- #include <linux/fault-inject.h> 21110ffebbeSMauro Carvalho Chehab 21210ffebbeSMauro Carvalho Chehab- define the fault attributes 21310ffebbeSMauro Carvalho Chehab 21410ffebbeSMauro Carvalho Chehab DECLARE_FAULT_ATTR(name); 21510ffebbeSMauro Carvalho Chehab 21610ffebbeSMauro Carvalho Chehab Please see the definition of struct fault_attr in fault-inject.h 21710ffebbeSMauro Carvalho Chehab for details. 21810ffebbeSMauro Carvalho Chehab 21910ffebbeSMauro Carvalho Chehab- provide a way to configure fault attributes 22010ffebbeSMauro Carvalho Chehab 22110ffebbeSMauro Carvalho Chehab- boot option 22210ffebbeSMauro Carvalho Chehab 22310ffebbeSMauro Carvalho Chehab If you need to enable the fault injection capability from boot time, you can 22410ffebbeSMauro Carvalho Chehab provide boot option to configure it. There is a helper function for it: 22510ffebbeSMauro Carvalho Chehab 22610ffebbeSMauro Carvalho Chehab setup_fault_attr(attr, str); 22710ffebbeSMauro Carvalho Chehab 22810ffebbeSMauro Carvalho Chehab- debugfs entries 22910ffebbeSMauro Carvalho Chehab 230*2c739cedSAlbert van der Linde failslab, fail_page_alloc, fail_usercopy, and fail_make_request use this way. 23110ffebbeSMauro Carvalho Chehab Helper functions: 23210ffebbeSMauro Carvalho Chehab 23310ffebbeSMauro Carvalho Chehab fault_create_debugfs_attr(name, parent, attr); 23410ffebbeSMauro Carvalho Chehab 23510ffebbeSMauro Carvalho Chehab- module parameters 23610ffebbeSMauro Carvalho Chehab 23710ffebbeSMauro Carvalho Chehab If the scope of the fault injection capability is limited to a 23810ffebbeSMauro Carvalho Chehab single kernel module, it is better to provide module parameters to 23910ffebbeSMauro Carvalho Chehab configure the fault attributes. 24010ffebbeSMauro Carvalho Chehab 24110ffebbeSMauro Carvalho Chehab- add a hook to insert failures 24210ffebbeSMauro Carvalho Chehab 24310ffebbeSMauro Carvalho Chehab Upon should_fail() returning true, client code should inject a failure: 24410ffebbeSMauro Carvalho Chehab 24510ffebbeSMauro Carvalho Chehab should_fail(attr, size); 24610ffebbeSMauro Carvalho Chehab 24710ffebbeSMauro Carvalho ChehabApplication Examples 24810ffebbeSMauro Carvalho Chehab-------------------- 24910ffebbeSMauro Carvalho Chehab 25010ffebbeSMauro Carvalho Chehab- Inject slab allocation failures into module init/exit code:: 25110ffebbeSMauro Carvalho Chehab 25210ffebbeSMauro Carvalho Chehab #!/bin/bash 25310ffebbeSMauro Carvalho Chehab 25410ffebbeSMauro Carvalho Chehab FAILTYPE=failslab 25510ffebbeSMauro Carvalho Chehab echo Y > /sys/kernel/debug/$FAILTYPE/task-filter 25610ffebbeSMauro Carvalho Chehab echo 10 > /sys/kernel/debug/$FAILTYPE/probability 25710ffebbeSMauro Carvalho Chehab echo 100 > /sys/kernel/debug/$FAILTYPE/interval 25810ffebbeSMauro Carvalho Chehab echo -1 > /sys/kernel/debug/$FAILTYPE/times 25910ffebbeSMauro Carvalho Chehab echo 0 > /sys/kernel/debug/$FAILTYPE/space 26010ffebbeSMauro Carvalho Chehab echo 2 > /sys/kernel/debug/$FAILTYPE/verbose 26110ffebbeSMauro Carvalho Chehab echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-wait 26210ffebbeSMauro Carvalho Chehab 26310ffebbeSMauro Carvalho Chehab faulty_system() 26410ffebbeSMauro Carvalho Chehab { 26510ffebbeSMauro Carvalho Chehab bash -c "echo 1 > /proc/self/make-it-fail && exec $*" 26610ffebbeSMauro Carvalho Chehab } 26710ffebbeSMauro Carvalho Chehab 26810ffebbeSMauro Carvalho Chehab if [ $# -eq 0 ] 26910ffebbeSMauro Carvalho Chehab then 27010ffebbeSMauro Carvalho Chehab echo "Usage: $0 modulename [ modulename ... ]" 27110ffebbeSMauro Carvalho Chehab exit 1 27210ffebbeSMauro Carvalho Chehab fi 27310ffebbeSMauro Carvalho Chehab 27410ffebbeSMauro Carvalho Chehab for m in $* 27510ffebbeSMauro Carvalho Chehab do 27610ffebbeSMauro Carvalho Chehab echo inserting $m... 27710ffebbeSMauro Carvalho Chehab faulty_system modprobe $m 27810ffebbeSMauro Carvalho Chehab 27910ffebbeSMauro Carvalho Chehab echo removing $m... 28010ffebbeSMauro Carvalho Chehab faulty_system modprobe -r $m 28110ffebbeSMauro Carvalho Chehab done 28210ffebbeSMauro Carvalho Chehab 28310ffebbeSMauro Carvalho Chehab------------------------------------------------------------------------------ 28410ffebbeSMauro Carvalho Chehab 28510ffebbeSMauro Carvalho Chehab- Inject page allocation failures only for a specific module:: 28610ffebbeSMauro Carvalho Chehab 28710ffebbeSMauro Carvalho Chehab #!/bin/bash 28810ffebbeSMauro Carvalho Chehab 28910ffebbeSMauro Carvalho Chehab FAILTYPE=fail_page_alloc 29010ffebbeSMauro Carvalho Chehab module=$1 29110ffebbeSMauro Carvalho Chehab 29210ffebbeSMauro Carvalho Chehab if [ -z $module ] 29310ffebbeSMauro Carvalho Chehab then 29410ffebbeSMauro Carvalho Chehab echo "Usage: $0 <modulename>" 29510ffebbeSMauro Carvalho Chehab exit 1 29610ffebbeSMauro Carvalho Chehab fi 29710ffebbeSMauro Carvalho Chehab 29810ffebbeSMauro Carvalho Chehab modprobe $module 29910ffebbeSMauro Carvalho Chehab 30010ffebbeSMauro Carvalho Chehab if [ ! -d /sys/module/$module/sections ] 30110ffebbeSMauro Carvalho Chehab then 30210ffebbeSMauro Carvalho Chehab echo Module $module is not loaded 30310ffebbeSMauro Carvalho Chehab exit 1 30410ffebbeSMauro Carvalho Chehab fi 30510ffebbeSMauro Carvalho Chehab 30610ffebbeSMauro Carvalho Chehab cat /sys/module/$module/sections/.text > /sys/kernel/debug/$FAILTYPE/require-start 30710ffebbeSMauro Carvalho Chehab cat /sys/module/$module/sections/.data > /sys/kernel/debug/$FAILTYPE/require-end 30810ffebbeSMauro Carvalho Chehab 30910ffebbeSMauro Carvalho Chehab echo N > /sys/kernel/debug/$FAILTYPE/task-filter 31010ffebbeSMauro Carvalho Chehab echo 10 > /sys/kernel/debug/$FAILTYPE/probability 31110ffebbeSMauro Carvalho Chehab echo 100 > /sys/kernel/debug/$FAILTYPE/interval 31210ffebbeSMauro Carvalho Chehab echo -1 > /sys/kernel/debug/$FAILTYPE/times 31310ffebbeSMauro Carvalho Chehab echo 0 > /sys/kernel/debug/$FAILTYPE/space 31410ffebbeSMauro Carvalho Chehab echo 2 > /sys/kernel/debug/$FAILTYPE/verbose 31510ffebbeSMauro Carvalho Chehab echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-wait 31610ffebbeSMauro Carvalho Chehab echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-highmem 31710ffebbeSMauro Carvalho Chehab echo 10 > /sys/kernel/debug/$FAILTYPE/stacktrace-depth 31810ffebbeSMauro Carvalho Chehab 31910ffebbeSMauro Carvalho Chehab trap "echo 0 > /sys/kernel/debug/$FAILTYPE/probability" SIGINT SIGTERM EXIT 32010ffebbeSMauro Carvalho Chehab 32110ffebbeSMauro Carvalho Chehab echo "Injecting errors into the module $module... (interrupt to stop)" 32210ffebbeSMauro Carvalho Chehab sleep 1000000 32310ffebbeSMauro Carvalho Chehab 32410ffebbeSMauro Carvalho Chehab------------------------------------------------------------------------------ 32510ffebbeSMauro Carvalho Chehab 32610ffebbeSMauro Carvalho Chehab- Inject open_ctree error while btrfs mount:: 32710ffebbeSMauro Carvalho Chehab 32810ffebbeSMauro Carvalho Chehab #!/bin/bash 32910ffebbeSMauro Carvalho Chehab 33010ffebbeSMauro Carvalho Chehab rm -f testfile.img 33110ffebbeSMauro Carvalho Chehab dd if=/dev/zero of=testfile.img bs=1M seek=1000 count=1 33210ffebbeSMauro Carvalho Chehab DEVICE=$(losetup --show -f testfile.img) 33310ffebbeSMauro Carvalho Chehab mkfs.btrfs -f $DEVICE 33410ffebbeSMauro Carvalho Chehab mkdir -p tmpmnt 33510ffebbeSMauro Carvalho Chehab 33610ffebbeSMauro Carvalho Chehab FAILTYPE=fail_function 33710ffebbeSMauro Carvalho Chehab FAILFUNC=open_ctree 33810ffebbeSMauro Carvalho Chehab echo $FAILFUNC > /sys/kernel/debug/$FAILTYPE/inject 33910ffebbeSMauro Carvalho Chehab echo -12 > /sys/kernel/debug/$FAILTYPE/$FAILFUNC/retval 34010ffebbeSMauro Carvalho Chehab echo N > /sys/kernel/debug/$FAILTYPE/task-filter 34110ffebbeSMauro Carvalho Chehab echo 100 > /sys/kernel/debug/$FAILTYPE/probability 34210ffebbeSMauro Carvalho Chehab echo 0 > /sys/kernel/debug/$FAILTYPE/interval 34310ffebbeSMauro Carvalho Chehab echo -1 > /sys/kernel/debug/$FAILTYPE/times 34410ffebbeSMauro Carvalho Chehab echo 0 > /sys/kernel/debug/$FAILTYPE/space 34510ffebbeSMauro Carvalho Chehab echo 1 > /sys/kernel/debug/$FAILTYPE/verbose 34610ffebbeSMauro Carvalho Chehab 34710ffebbeSMauro Carvalho Chehab mount -t btrfs $DEVICE tmpmnt 34810ffebbeSMauro Carvalho Chehab if [ $? -ne 0 ] 34910ffebbeSMauro Carvalho Chehab then 35010ffebbeSMauro Carvalho Chehab echo "SUCCESS!" 35110ffebbeSMauro Carvalho Chehab else 35210ffebbeSMauro Carvalho Chehab echo "FAILED!" 35310ffebbeSMauro Carvalho Chehab umount tmpmnt 35410ffebbeSMauro Carvalho Chehab fi 35510ffebbeSMauro Carvalho Chehab 35610ffebbeSMauro Carvalho Chehab echo > /sys/kernel/debug/$FAILTYPE/inject 35710ffebbeSMauro Carvalho Chehab 35810ffebbeSMauro Carvalho Chehab rmdir tmpmnt 35910ffebbeSMauro Carvalho Chehab losetup -d $DEVICE 36010ffebbeSMauro Carvalho Chehab rm testfile.img 36110ffebbeSMauro Carvalho Chehab 36210ffebbeSMauro Carvalho Chehab 36310ffebbeSMauro Carvalho ChehabTool to run command with failslab or fail_page_alloc 36410ffebbeSMauro Carvalho Chehab---------------------------------------------------- 36510ffebbeSMauro Carvalho ChehabIn order to make it easier to accomplish the tasks mentioned above, we can use 36610ffebbeSMauro Carvalho Chehabtools/testing/fault-injection/failcmd.sh. Please run a command 36710ffebbeSMauro Carvalho Chehab"./tools/testing/fault-injection/failcmd.sh --help" for more information and 36810ffebbeSMauro Carvalho Chehabsee the following examples. 36910ffebbeSMauro Carvalho Chehab 37010ffebbeSMauro Carvalho ChehabExamples: 37110ffebbeSMauro Carvalho Chehab 37210ffebbeSMauro Carvalho ChehabRun a command "make -C tools/testing/selftests/ run_tests" with injecting slab 37310ffebbeSMauro Carvalho Chehaballocation failure:: 37410ffebbeSMauro Carvalho Chehab 37510ffebbeSMauro Carvalho Chehab # ./tools/testing/fault-injection/failcmd.sh \ 37610ffebbeSMauro Carvalho Chehab -- make -C tools/testing/selftests/ run_tests 37710ffebbeSMauro Carvalho Chehab 37810ffebbeSMauro Carvalho ChehabSame as above except to specify 100 times failures at most instead of one time 37910ffebbeSMauro Carvalho Chehabat most by default:: 38010ffebbeSMauro Carvalho Chehab 38110ffebbeSMauro Carvalho Chehab # ./tools/testing/fault-injection/failcmd.sh --times=100 \ 38210ffebbeSMauro Carvalho Chehab -- make -C tools/testing/selftests/ run_tests 38310ffebbeSMauro Carvalho Chehab 38410ffebbeSMauro Carvalho ChehabSame as above except to inject page allocation failure instead of slab 38510ffebbeSMauro Carvalho Chehaballocation failure:: 38610ffebbeSMauro Carvalho Chehab 38710ffebbeSMauro Carvalho Chehab # env FAILCMD_TYPE=fail_page_alloc \ 38810ffebbeSMauro Carvalho Chehab ./tools/testing/fault-injection/failcmd.sh --times=100 \ 38910ffebbeSMauro Carvalho Chehab -- make -C tools/testing/selftests/ run_tests 39010ffebbeSMauro Carvalho Chehab 39110ffebbeSMauro Carvalho ChehabSystematic faults using fail-nth 39210ffebbeSMauro Carvalho Chehab--------------------------------- 39310ffebbeSMauro Carvalho Chehab 39410ffebbeSMauro Carvalho ChehabThe following code systematically faults 0-th, 1-st, 2-nd and so on 39510ffebbeSMauro Carvalho Chehabcapabilities in the socketpair() system call:: 39610ffebbeSMauro Carvalho Chehab 39710ffebbeSMauro Carvalho Chehab #include <sys/types.h> 39810ffebbeSMauro Carvalho Chehab #include <sys/stat.h> 39910ffebbeSMauro Carvalho Chehab #include <sys/socket.h> 40010ffebbeSMauro Carvalho Chehab #include <sys/syscall.h> 40110ffebbeSMauro Carvalho Chehab #include <fcntl.h> 40210ffebbeSMauro Carvalho Chehab #include <unistd.h> 40310ffebbeSMauro Carvalho Chehab #include <string.h> 40410ffebbeSMauro Carvalho Chehab #include <stdlib.h> 40510ffebbeSMauro Carvalho Chehab #include <stdio.h> 40610ffebbeSMauro Carvalho Chehab #include <errno.h> 40710ffebbeSMauro Carvalho Chehab 40810ffebbeSMauro Carvalho Chehab int main() 40910ffebbeSMauro Carvalho Chehab { 41010ffebbeSMauro Carvalho Chehab int i, err, res, fail_nth, fds[2]; 41110ffebbeSMauro Carvalho Chehab char buf[128]; 41210ffebbeSMauro Carvalho Chehab 41310ffebbeSMauro Carvalho Chehab system("echo N > /sys/kernel/debug/failslab/ignore-gfp-wait"); 41410ffebbeSMauro Carvalho Chehab sprintf(buf, "/proc/self/task/%ld/fail-nth", syscall(SYS_gettid)); 41510ffebbeSMauro Carvalho Chehab fail_nth = open(buf, O_RDWR); 41610ffebbeSMauro Carvalho Chehab for (i = 1;; i++) { 41710ffebbeSMauro Carvalho Chehab sprintf(buf, "%d", i); 41810ffebbeSMauro Carvalho Chehab write(fail_nth, buf, strlen(buf)); 41910ffebbeSMauro Carvalho Chehab res = socketpair(AF_LOCAL, SOCK_STREAM, 0, fds); 42010ffebbeSMauro Carvalho Chehab err = errno; 42110ffebbeSMauro Carvalho Chehab pread(fail_nth, buf, sizeof(buf), 0); 42210ffebbeSMauro Carvalho Chehab if (res == 0) { 42310ffebbeSMauro Carvalho Chehab close(fds[0]); 42410ffebbeSMauro Carvalho Chehab close(fds[1]); 42510ffebbeSMauro Carvalho Chehab } 42610ffebbeSMauro Carvalho Chehab printf("%d-th fault %c: res=%d/%d\n", i, atoi(buf) ? 'N' : 'Y', 42710ffebbeSMauro Carvalho Chehab res, err); 42810ffebbeSMauro Carvalho Chehab if (atoi(buf)) 42910ffebbeSMauro Carvalho Chehab break; 43010ffebbeSMauro Carvalho Chehab } 43110ffebbeSMauro Carvalho Chehab return 0; 43210ffebbeSMauro Carvalho Chehab } 43310ffebbeSMauro Carvalho Chehab 43410ffebbeSMauro Carvalho ChehabAn example output:: 43510ffebbeSMauro Carvalho Chehab 43610ffebbeSMauro Carvalho Chehab 1-th fault Y: res=-1/23 43710ffebbeSMauro Carvalho Chehab 2-th fault Y: res=-1/23 43810ffebbeSMauro Carvalho Chehab 3-th fault Y: res=-1/12 43910ffebbeSMauro Carvalho Chehab 4-th fault Y: res=-1/12 44010ffebbeSMauro Carvalho Chehab 5-th fault Y: res=-1/23 44110ffebbeSMauro Carvalho Chehab 6-th fault Y: res=-1/23 44210ffebbeSMauro Carvalho Chehab 7-th fault Y: res=-1/23 44310ffebbeSMauro Carvalho Chehab 8-th fault Y: res=-1/12 44410ffebbeSMauro Carvalho Chehab 9-th fault Y: res=-1/12 44510ffebbeSMauro Carvalho Chehab 10-th fault Y: res=-1/12 44610ffebbeSMauro Carvalho Chehab 11-th fault Y: res=-1/12 44710ffebbeSMauro Carvalho Chehab 12-th fault Y: res=-1/12 44810ffebbeSMauro Carvalho Chehab 13-th fault Y: res=-1/12 44910ffebbeSMauro Carvalho Chehab 14-th fault Y: res=-1/12 45010ffebbeSMauro Carvalho Chehab 15-th fault Y: res=-1/12 45110ffebbeSMauro Carvalho Chehab 16-th fault N: res=0/12 452