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 192c739cedSAlbert van der Linde- fail_usercopy 202c739cedSAlbert van der Linde 212c739cedSAlbert van der Linde injects failures in user memory access functions. (copy_from_user(), get_user(), ...) 222c739cedSAlbert van der Linde 2310ffebbeSMauro Carvalho Chehab- fail_futex 2410ffebbeSMauro Carvalho Chehab 2510ffebbeSMauro Carvalho Chehab injects futex deadlock and uaddr fault errors. 2610ffebbeSMauro Carvalho Chehab 27*400edd8cSChuck Lever- fail_sunrpc 28*400edd8cSChuck Lever 29*400edd8cSChuck Lever injects kernel RPC client and server failures. 30*400edd8cSChuck Lever 3110ffebbeSMauro Carvalho Chehab- fail_make_request 3210ffebbeSMauro Carvalho Chehab 3310ffebbeSMauro Carvalho Chehab injects disk IO errors on devices permitted by setting 3410ffebbeSMauro Carvalho Chehab /sys/block/<device>/make-it-fail or 35ed00aabdSChristoph Hellwig /sys/block/<device>/<partition>/make-it-fail. (submit_bio_noacct()) 3610ffebbeSMauro Carvalho Chehab 3710ffebbeSMauro Carvalho Chehab- fail_mmc_request 3810ffebbeSMauro Carvalho Chehab 3910ffebbeSMauro Carvalho Chehab injects MMC data errors on devices permitted by setting 4010ffebbeSMauro Carvalho Chehab debugfs entries under /sys/kernel/debug/mmc0/fail_mmc_request 4110ffebbeSMauro Carvalho Chehab 4210ffebbeSMauro Carvalho Chehab- fail_function 4310ffebbeSMauro Carvalho Chehab 4410ffebbeSMauro Carvalho Chehab injects error return on specific functions, which are marked by 4510ffebbeSMauro Carvalho Chehab ALLOW_ERROR_INJECTION() macro, by setting debugfs entries 4610ffebbeSMauro Carvalho Chehab under /sys/kernel/debug/fail_function. No boot option supported. 4710ffebbeSMauro Carvalho Chehab 4810ffebbeSMauro Carvalho Chehab- NVMe fault injection 4910ffebbeSMauro Carvalho Chehab 5010ffebbeSMauro Carvalho Chehab inject NVMe status code and retry flag on devices permitted by setting 5110ffebbeSMauro Carvalho Chehab debugfs entries under /sys/kernel/debug/nvme*/fault_inject. The default 5210ffebbeSMauro Carvalho Chehab status code is NVME_SC_INVALID_OPCODE with no retry. The status code and 5310ffebbeSMauro Carvalho Chehab retry flag can be set via the debugfs. 5410ffebbeSMauro Carvalho Chehab 5510ffebbeSMauro Carvalho Chehab 5610ffebbeSMauro Carvalho ChehabConfigure fault-injection capabilities behavior 5710ffebbeSMauro Carvalho Chehab----------------------------------------------- 5810ffebbeSMauro Carvalho Chehab 5910ffebbeSMauro Carvalho Chehabdebugfs entries 6010ffebbeSMauro Carvalho Chehab^^^^^^^^^^^^^^^ 6110ffebbeSMauro Carvalho Chehab 6210ffebbeSMauro Carvalho Chehabfault-inject-debugfs kernel module provides some debugfs entries for runtime 6310ffebbeSMauro Carvalho Chehabconfiguration of fault-injection capabilities. 6410ffebbeSMauro Carvalho Chehab 6510ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail*/probability: 6610ffebbeSMauro Carvalho Chehab 6710ffebbeSMauro Carvalho Chehab likelihood of failure injection, in percent. 6810ffebbeSMauro Carvalho Chehab 6910ffebbeSMauro Carvalho Chehab Format: <percent> 7010ffebbeSMauro Carvalho Chehab 7110ffebbeSMauro Carvalho Chehab Note that one-failure-per-hundred is a very high error rate 7210ffebbeSMauro Carvalho Chehab for some testcases. Consider setting probability=100 and configure 7310ffebbeSMauro Carvalho Chehab /sys/kernel/debug/fail*/interval for such testcases. 7410ffebbeSMauro Carvalho Chehab 7510ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail*/interval: 7610ffebbeSMauro Carvalho Chehab 7710ffebbeSMauro Carvalho Chehab specifies the interval between failures, for calls to 7810ffebbeSMauro Carvalho Chehab should_fail() that pass all the other tests. 7910ffebbeSMauro Carvalho Chehab 8010ffebbeSMauro Carvalho Chehab Note that if you enable this, by setting interval>1, you will 8110ffebbeSMauro Carvalho Chehab probably want to set probability=100. 8210ffebbeSMauro Carvalho Chehab 8310ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail*/times: 8410ffebbeSMauro Carvalho Chehab 8500574752SWolfram Sang specifies how many times failures may happen at most. A value of -1 8600574752SWolfram Sang means "no limit". Note, though, that this file only accepts unsigned 8700574752SWolfram Sang values. So, if you want to specify -1, you better use 'printf' instead 8800574752SWolfram Sang of 'echo', e.g.: $ printf %#x -1 > times 8910ffebbeSMauro Carvalho Chehab 9010ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail*/space: 9110ffebbeSMauro Carvalho Chehab 9210ffebbeSMauro Carvalho Chehab specifies an initial resource "budget", decremented by "size" 9310ffebbeSMauro Carvalho Chehab on each call to should_fail(,size). Failure injection is 9410ffebbeSMauro Carvalho Chehab suppressed until "space" reaches zero. 9510ffebbeSMauro Carvalho Chehab 9610ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail*/verbose 9710ffebbeSMauro Carvalho Chehab 9810ffebbeSMauro Carvalho Chehab Format: { 0 | 1 | 2 } 9910ffebbeSMauro Carvalho Chehab 10010ffebbeSMauro Carvalho Chehab specifies the verbosity of the messages when failure is 10110ffebbeSMauro Carvalho Chehab injected. '0' means no messages; '1' will print only a single 10210ffebbeSMauro Carvalho Chehab log line per failure; '2' will print a call trace too -- useful 10310ffebbeSMauro Carvalho Chehab to debug the problems revealed by fault injection. 10410ffebbeSMauro Carvalho Chehab 10510ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail*/task-filter: 10610ffebbeSMauro Carvalho Chehab 10710ffebbeSMauro Carvalho Chehab Format: { 'Y' | 'N' } 10810ffebbeSMauro Carvalho Chehab 10910ffebbeSMauro Carvalho Chehab A value of 'N' disables filtering by process (default). 11010ffebbeSMauro Carvalho Chehab Any positive value limits failures to only processes indicated by 11110ffebbeSMauro Carvalho Chehab /proc/<pid>/make-it-fail==1. 11210ffebbeSMauro Carvalho Chehab 11310ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail*/require-start, 11410ffebbeSMauro Carvalho Chehab /sys/kernel/debug/fail*/require-end, 11510ffebbeSMauro Carvalho Chehab /sys/kernel/debug/fail*/reject-start, 11610ffebbeSMauro Carvalho Chehab /sys/kernel/debug/fail*/reject-end: 11710ffebbeSMauro Carvalho Chehab 11810ffebbeSMauro Carvalho Chehab specifies the range of virtual addresses tested during 11910ffebbeSMauro Carvalho Chehab stacktrace walking. Failure is injected only if some caller 12010ffebbeSMauro Carvalho Chehab in the walked stacktrace lies within the required range, and 12110ffebbeSMauro Carvalho Chehab none lies within the rejected range. 12210ffebbeSMauro Carvalho Chehab Default required range is [0,ULONG_MAX) (whole of virtual address space). 12310ffebbeSMauro Carvalho Chehab Default rejected range is [0,0). 12410ffebbeSMauro Carvalho Chehab 12510ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail*/stacktrace-depth: 12610ffebbeSMauro Carvalho Chehab 12710ffebbeSMauro Carvalho Chehab specifies the maximum stacktrace depth walked during search 12810ffebbeSMauro Carvalho Chehab for a caller within [require-start,require-end) OR 12910ffebbeSMauro Carvalho Chehab [reject-start,reject-end). 13010ffebbeSMauro Carvalho Chehab 13110ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail_page_alloc/ignore-gfp-highmem: 13210ffebbeSMauro Carvalho Chehab 13310ffebbeSMauro Carvalho Chehab Format: { 'Y' | 'N' } 13410ffebbeSMauro Carvalho Chehab 13510ffebbeSMauro Carvalho Chehab default is 'N', setting it to 'Y' won't inject failures into 13610ffebbeSMauro Carvalho Chehab highmem/user allocations. 13710ffebbeSMauro Carvalho Chehab 13810ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/failslab/ignore-gfp-wait: 13910ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail_page_alloc/ignore-gfp-wait: 14010ffebbeSMauro Carvalho Chehab 14110ffebbeSMauro Carvalho Chehab Format: { 'Y' | 'N' } 14210ffebbeSMauro Carvalho Chehab 14310ffebbeSMauro Carvalho Chehab default is 'N', setting it to 'Y' will inject failures 14410ffebbeSMauro Carvalho Chehab only into non-sleep allocations (GFP_ATOMIC allocations). 14510ffebbeSMauro Carvalho Chehab 14610ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail_page_alloc/min-order: 14710ffebbeSMauro Carvalho Chehab 14810ffebbeSMauro Carvalho Chehab specifies the minimum page allocation order to be injected 14910ffebbeSMauro Carvalho Chehab failures. 15010ffebbeSMauro Carvalho Chehab 15110ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail_futex/ignore-private: 15210ffebbeSMauro Carvalho Chehab 15310ffebbeSMauro Carvalho Chehab Format: { 'Y' | 'N' } 15410ffebbeSMauro Carvalho Chehab 15510ffebbeSMauro Carvalho Chehab default is 'N', setting it to 'Y' will disable failure injections 15610ffebbeSMauro Carvalho Chehab when dealing with private (address space) futexes. 15710ffebbeSMauro Carvalho Chehab 158*400edd8cSChuck Lever- /sys/kernel/debug/fail_sunrpc/ignore-client-disconnect: 159*400edd8cSChuck Lever 160*400edd8cSChuck Lever Format: { 'Y' | 'N' } 161*400edd8cSChuck Lever 162*400edd8cSChuck Lever default is 'N', setting it to 'Y' will disable disconnect 163*400edd8cSChuck Lever injection on the RPC client. 164*400edd8cSChuck Lever 165*400edd8cSChuck Lever- /sys/kernel/debug/fail_sunrpc/ignore-server-disconnect: 166*400edd8cSChuck Lever 167*400edd8cSChuck Lever Format: { 'Y' | 'N' } 168*400edd8cSChuck Lever 169*400edd8cSChuck Lever default is 'N', setting it to 'Y' will disable disconnect 170*400edd8cSChuck Lever injection on the RPC server. 171*400edd8cSChuck Lever 17210ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail_function/inject: 17310ffebbeSMauro Carvalho Chehab 17410ffebbeSMauro Carvalho Chehab Format: { 'function-name' | '!function-name' | '' } 17510ffebbeSMauro Carvalho Chehab 17610ffebbeSMauro Carvalho Chehab specifies the target function of error injection by name. 17710ffebbeSMauro Carvalho Chehab If the function name leads '!' prefix, given function is 17810ffebbeSMauro Carvalho Chehab removed from injection list. If nothing specified ('') 17910ffebbeSMauro Carvalho Chehab injection list is cleared. 18010ffebbeSMauro Carvalho Chehab 18110ffebbeSMauro Carvalho Chehab- /sys/kernel/debug/fail_function/injectable: 18210ffebbeSMauro Carvalho Chehab 18310ffebbeSMauro Carvalho Chehab (read only) shows error injectable functions and what type of 18410ffebbeSMauro Carvalho Chehab error values can be specified. The error type will be one of 18510ffebbeSMauro Carvalho Chehab below; 18610ffebbeSMauro Carvalho Chehab - NULL: retval must be 0. 18710ffebbeSMauro Carvalho Chehab - ERRNO: retval must be -1 to -MAX_ERRNO (-4096). 18810ffebbeSMauro Carvalho Chehab - ERR_NULL: retval must be 0 or -1 to -MAX_ERRNO (-4096). 18910ffebbeSMauro Carvalho Chehab 19000574752SWolfram Sang- /sys/kernel/debug/fail_function/<function-name>/retval: 19110ffebbeSMauro Carvalho Chehab 19200574752SWolfram Sang specifies the "error" return value to inject to the given function. 19300574752SWolfram Sang This will be created when the user specifies a new injection entry. 19400574752SWolfram Sang Note that this file only accepts unsigned values. So, if you want to 19500574752SWolfram Sang use a negative errno, you better use 'printf' instead of 'echo', e.g.: 19600574752SWolfram Sang $ printf %#x -12 > retval 19710ffebbeSMauro Carvalho Chehab 19810ffebbeSMauro Carvalho ChehabBoot option 19910ffebbeSMauro Carvalho Chehab^^^^^^^^^^^ 20010ffebbeSMauro Carvalho Chehab 20110ffebbeSMauro Carvalho ChehabIn order to inject faults while debugfs is not available (early boot time), 20210ffebbeSMauro Carvalho Chehabuse the boot option:: 20310ffebbeSMauro Carvalho Chehab 20410ffebbeSMauro Carvalho Chehab failslab= 20510ffebbeSMauro Carvalho Chehab fail_page_alloc= 2062c739cedSAlbert van der Linde fail_usercopy= 20710ffebbeSMauro Carvalho Chehab fail_make_request= 20810ffebbeSMauro Carvalho Chehab fail_futex= 20910ffebbeSMauro Carvalho Chehab mmc_core.fail_request=<interval>,<probability>,<space>,<times> 21010ffebbeSMauro Carvalho Chehab 21110ffebbeSMauro Carvalho Chehabproc entries 21210ffebbeSMauro Carvalho Chehab^^^^^^^^^^^^ 21310ffebbeSMauro Carvalho Chehab 21410ffebbeSMauro Carvalho Chehab- /proc/<pid>/fail-nth, 21510ffebbeSMauro Carvalho Chehab /proc/self/task/<tid>/fail-nth: 21610ffebbeSMauro Carvalho Chehab 21710ffebbeSMauro Carvalho Chehab Write to this file of integer N makes N-th call in the task fail. 21810ffebbeSMauro Carvalho Chehab Read from this file returns a integer value. A value of '0' indicates 21910ffebbeSMauro Carvalho Chehab that the fault setup with a previous write to this file was injected. 22010ffebbeSMauro Carvalho Chehab A positive integer N indicates that the fault wasn't yet injected. 22110ffebbeSMauro Carvalho Chehab Note that this file enables all types of faults (slab, futex, etc). 22210ffebbeSMauro Carvalho Chehab This setting takes precedence over all other generic debugfs settings 22310ffebbeSMauro Carvalho Chehab like probability, interval, times, etc. But per-capability settings 22410ffebbeSMauro Carvalho Chehab (e.g. fail_futex/ignore-private) take precedence over it. 22510ffebbeSMauro Carvalho Chehab 22610ffebbeSMauro Carvalho Chehab This feature is intended for systematic testing of faults in a single 22710ffebbeSMauro Carvalho Chehab system call. See an example below. 22810ffebbeSMauro Carvalho Chehab 22910ffebbeSMauro Carvalho ChehabHow to add new fault injection capability 23010ffebbeSMauro Carvalho Chehab----------------------------------------- 23110ffebbeSMauro Carvalho Chehab 23210ffebbeSMauro Carvalho Chehab- #include <linux/fault-inject.h> 23310ffebbeSMauro Carvalho Chehab 23410ffebbeSMauro Carvalho Chehab- define the fault attributes 23510ffebbeSMauro Carvalho Chehab 23610ffebbeSMauro Carvalho Chehab DECLARE_FAULT_ATTR(name); 23710ffebbeSMauro Carvalho Chehab 23810ffebbeSMauro Carvalho Chehab Please see the definition of struct fault_attr in fault-inject.h 23910ffebbeSMauro Carvalho Chehab for details. 24010ffebbeSMauro Carvalho Chehab 24110ffebbeSMauro Carvalho Chehab- provide a way to configure fault attributes 24210ffebbeSMauro Carvalho Chehab 24310ffebbeSMauro Carvalho Chehab- boot option 24410ffebbeSMauro Carvalho Chehab 24510ffebbeSMauro Carvalho Chehab If you need to enable the fault injection capability from boot time, you can 24610ffebbeSMauro Carvalho Chehab provide boot option to configure it. There is a helper function for it: 24710ffebbeSMauro Carvalho Chehab 24810ffebbeSMauro Carvalho Chehab setup_fault_attr(attr, str); 24910ffebbeSMauro Carvalho Chehab 25010ffebbeSMauro Carvalho Chehab- debugfs entries 25110ffebbeSMauro Carvalho Chehab 2522c739cedSAlbert van der Linde failslab, fail_page_alloc, fail_usercopy, and fail_make_request use this way. 25310ffebbeSMauro Carvalho Chehab Helper functions: 25410ffebbeSMauro Carvalho Chehab 25510ffebbeSMauro Carvalho Chehab fault_create_debugfs_attr(name, parent, attr); 25610ffebbeSMauro Carvalho Chehab 25710ffebbeSMauro Carvalho Chehab- module parameters 25810ffebbeSMauro Carvalho Chehab 25910ffebbeSMauro Carvalho Chehab If the scope of the fault injection capability is limited to a 26010ffebbeSMauro Carvalho Chehab single kernel module, it is better to provide module parameters to 26110ffebbeSMauro Carvalho Chehab configure the fault attributes. 26210ffebbeSMauro Carvalho Chehab 26310ffebbeSMauro Carvalho Chehab- add a hook to insert failures 26410ffebbeSMauro Carvalho Chehab 26510ffebbeSMauro Carvalho Chehab Upon should_fail() returning true, client code should inject a failure: 26610ffebbeSMauro Carvalho Chehab 26710ffebbeSMauro Carvalho Chehab should_fail(attr, size); 26810ffebbeSMauro Carvalho Chehab 26910ffebbeSMauro Carvalho ChehabApplication Examples 27010ffebbeSMauro Carvalho Chehab-------------------- 27110ffebbeSMauro Carvalho Chehab 27210ffebbeSMauro Carvalho Chehab- Inject slab allocation failures into module init/exit code:: 27310ffebbeSMauro Carvalho Chehab 27410ffebbeSMauro Carvalho Chehab #!/bin/bash 27510ffebbeSMauro Carvalho Chehab 27610ffebbeSMauro Carvalho Chehab FAILTYPE=failslab 27710ffebbeSMauro Carvalho Chehab echo Y > /sys/kernel/debug/$FAILTYPE/task-filter 27810ffebbeSMauro Carvalho Chehab echo 10 > /sys/kernel/debug/$FAILTYPE/probability 27910ffebbeSMauro Carvalho Chehab echo 100 > /sys/kernel/debug/$FAILTYPE/interval 28000574752SWolfram Sang printf %#x -1 > /sys/kernel/debug/$FAILTYPE/times 28110ffebbeSMauro Carvalho Chehab echo 0 > /sys/kernel/debug/$FAILTYPE/space 28210ffebbeSMauro Carvalho Chehab echo 2 > /sys/kernel/debug/$FAILTYPE/verbose 28310ffebbeSMauro Carvalho Chehab echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-wait 28410ffebbeSMauro Carvalho Chehab 28510ffebbeSMauro Carvalho Chehab faulty_system() 28610ffebbeSMauro Carvalho Chehab { 28710ffebbeSMauro Carvalho Chehab bash -c "echo 1 > /proc/self/make-it-fail && exec $*" 28810ffebbeSMauro Carvalho Chehab } 28910ffebbeSMauro Carvalho Chehab 29010ffebbeSMauro Carvalho Chehab if [ $# -eq 0 ] 29110ffebbeSMauro Carvalho Chehab then 29210ffebbeSMauro Carvalho Chehab echo "Usage: $0 modulename [ modulename ... ]" 29310ffebbeSMauro Carvalho Chehab exit 1 29410ffebbeSMauro Carvalho Chehab fi 29510ffebbeSMauro Carvalho Chehab 29610ffebbeSMauro Carvalho Chehab for m in $* 29710ffebbeSMauro Carvalho Chehab do 29810ffebbeSMauro Carvalho Chehab echo inserting $m... 29910ffebbeSMauro Carvalho Chehab faulty_system modprobe $m 30010ffebbeSMauro Carvalho Chehab 30110ffebbeSMauro Carvalho Chehab echo removing $m... 30210ffebbeSMauro Carvalho Chehab faulty_system modprobe -r $m 30310ffebbeSMauro Carvalho Chehab done 30410ffebbeSMauro Carvalho Chehab 30510ffebbeSMauro Carvalho Chehab------------------------------------------------------------------------------ 30610ffebbeSMauro Carvalho Chehab 30710ffebbeSMauro Carvalho Chehab- Inject page allocation failures only for a specific module:: 30810ffebbeSMauro Carvalho Chehab 30910ffebbeSMauro Carvalho Chehab #!/bin/bash 31010ffebbeSMauro Carvalho Chehab 31110ffebbeSMauro Carvalho Chehab FAILTYPE=fail_page_alloc 31210ffebbeSMauro Carvalho Chehab module=$1 31310ffebbeSMauro Carvalho Chehab 31410ffebbeSMauro Carvalho Chehab if [ -z $module ] 31510ffebbeSMauro Carvalho Chehab then 31610ffebbeSMauro Carvalho Chehab echo "Usage: $0 <modulename>" 31710ffebbeSMauro Carvalho Chehab exit 1 31810ffebbeSMauro Carvalho Chehab fi 31910ffebbeSMauro Carvalho Chehab 32010ffebbeSMauro Carvalho Chehab modprobe $module 32110ffebbeSMauro Carvalho Chehab 32210ffebbeSMauro Carvalho Chehab if [ ! -d /sys/module/$module/sections ] 32310ffebbeSMauro Carvalho Chehab then 32410ffebbeSMauro Carvalho Chehab echo Module $module is not loaded 32510ffebbeSMauro Carvalho Chehab exit 1 32610ffebbeSMauro Carvalho Chehab fi 32710ffebbeSMauro Carvalho Chehab 32810ffebbeSMauro Carvalho Chehab cat /sys/module/$module/sections/.text > /sys/kernel/debug/$FAILTYPE/require-start 32910ffebbeSMauro Carvalho Chehab cat /sys/module/$module/sections/.data > /sys/kernel/debug/$FAILTYPE/require-end 33010ffebbeSMauro Carvalho Chehab 33110ffebbeSMauro Carvalho Chehab echo N > /sys/kernel/debug/$FAILTYPE/task-filter 33210ffebbeSMauro Carvalho Chehab echo 10 > /sys/kernel/debug/$FAILTYPE/probability 33310ffebbeSMauro Carvalho Chehab echo 100 > /sys/kernel/debug/$FAILTYPE/interval 33400574752SWolfram Sang printf %#x -1 > /sys/kernel/debug/$FAILTYPE/times 33510ffebbeSMauro Carvalho Chehab echo 0 > /sys/kernel/debug/$FAILTYPE/space 33610ffebbeSMauro Carvalho Chehab echo 2 > /sys/kernel/debug/$FAILTYPE/verbose 33710ffebbeSMauro Carvalho Chehab echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-wait 33810ffebbeSMauro Carvalho Chehab echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-highmem 33910ffebbeSMauro Carvalho Chehab echo 10 > /sys/kernel/debug/$FAILTYPE/stacktrace-depth 34010ffebbeSMauro Carvalho Chehab 34110ffebbeSMauro Carvalho Chehab trap "echo 0 > /sys/kernel/debug/$FAILTYPE/probability" SIGINT SIGTERM EXIT 34210ffebbeSMauro Carvalho Chehab 34310ffebbeSMauro Carvalho Chehab echo "Injecting errors into the module $module... (interrupt to stop)" 34410ffebbeSMauro Carvalho Chehab sleep 1000000 34510ffebbeSMauro Carvalho Chehab 34610ffebbeSMauro Carvalho Chehab------------------------------------------------------------------------------ 34710ffebbeSMauro Carvalho Chehab 34810ffebbeSMauro Carvalho Chehab- Inject open_ctree error while btrfs mount:: 34910ffebbeSMauro Carvalho Chehab 35010ffebbeSMauro Carvalho Chehab #!/bin/bash 35110ffebbeSMauro Carvalho Chehab 35210ffebbeSMauro Carvalho Chehab rm -f testfile.img 35310ffebbeSMauro Carvalho Chehab dd if=/dev/zero of=testfile.img bs=1M seek=1000 count=1 35410ffebbeSMauro Carvalho Chehab DEVICE=$(losetup --show -f testfile.img) 35510ffebbeSMauro Carvalho Chehab mkfs.btrfs -f $DEVICE 35610ffebbeSMauro Carvalho Chehab mkdir -p tmpmnt 35710ffebbeSMauro Carvalho Chehab 35810ffebbeSMauro Carvalho Chehab FAILTYPE=fail_function 35910ffebbeSMauro Carvalho Chehab FAILFUNC=open_ctree 36010ffebbeSMauro Carvalho Chehab echo $FAILFUNC > /sys/kernel/debug/$FAILTYPE/inject 36100574752SWolfram Sang printf %#x -12 > /sys/kernel/debug/$FAILTYPE/$FAILFUNC/retval 36210ffebbeSMauro Carvalho Chehab echo N > /sys/kernel/debug/$FAILTYPE/task-filter 36310ffebbeSMauro Carvalho Chehab echo 100 > /sys/kernel/debug/$FAILTYPE/probability 36410ffebbeSMauro Carvalho Chehab echo 0 > /sys/kernel/debug/$FAILTYPE/interval 36500574752SWolfram Sang printf %#x -1 > /sys/kernel/debug/$FAILTYPE/times 36610ffebbeSMauro Carvalho Chehab echo 0 > /sys/kernel/debug/$FAILTYPE/space 36710ffebbeSMauro Carvalho Chehab echo 1 > /sys/kernel/debug/$FAILTYPE/verbose 36810ffebbeSMauro Carvalho Chehab 36910ffebbeSMauro Carvalho Chehab mount -t btrfs $DEVICE tmpmnt 37010ffebbeSMauro Carvalho Chehab if [ $? -ne 0 ] 37110ffebbeSMauro Carvalho Chehab then 37210ffebbeSMauro Carvalho Chehab echo "SUCCESS!" 37310ffebbeSMauro Carvalho Chehab else 37410ffebbeSMauro Carvalho Chehab echo "FAILED!" 37510ffebbeSMauro Carvalho Chehab umount tmpmnt 37610ffebbeSMauro Carvalho Chehab fi 37710ffebbeSMauro Carvalho Chehab 37810ffebbeSMauro Carvalho Chehab echo > /sys/kernel/debug/$FAILTYPE/inject 37910ffebbeSMauro Carvalho Chehab 38010ffebbeSMauro Carvalho Chehab rmdir tmpmnt 38110ffebbeSMauro Carvalho Chehab losetup -d $DEVICE 38210ffebbeSMauro Carvalho Chehab rm testfile.img 38310ffebbeSMauro Carvalho Chehab 38410ffebbeSMauro Carvalho Chehab 38510ffebbeSMauro Carvalho ChehabTool to run command with failslab or fail_page_alloc 38610ffebbeSMauro Carvalho Chehab---------------------------------------------------- 38710ffebbeSMauro Carvalho ChehabIn order to make it easier to accomplish the tasks mentioned above, we can use 38810ffebbeSMauro Carvalho Chehabtools/testing/fault-injection/failcmd.sh. Please run a command 38910ffebbeSMauro Carvalho Chehab"./tools/testing/fault-injection/failcmd.sh --help" for more information and 39010ffebbeSMauro Carvalho Chehabsee the following examples. 39110ffebbeSMauro Carvalho Chehab 39210ffebbeSMauro Carvalho ChehabExamples: 39310ffebbeSMauro Carvalho Chehab 39410ffebbeSMauro Carvalho ChehabRun a command "make -C tools/testing/selftests/ run_tests" with injecting slab 39510ffebbeSMauro Carvalho Chehaballocation failure:: 39610ffebbeSMauro Carvalho Chehab 39710ffebbeSMauro Carvalho Chehab # ./tools/testing/fault-injection/failcmd.sh \ 39810ffebbeSMauro Carvalho Chehab -- make -C tools/testing/selftests/ run_tests 39910ffebbeSMauro Carvalho Chehab 40010ffebbeSMauro Carvalho ChehabSame as above except to specify 100 times failures at most instead of one time 40110ffebbeSMauro Carvalho Chehabat most by default:: 40210ffebbeSMauro Carvalho Chehab 40310ffebbeSMauro Carvalho Chehab # ./tools/testing/fault-injection/failcmd.sh --times=100 \ 40410ffebbeSMauro Carvalho Chehab -- make -C tools/testing/selftests/ run_tests 40510ffebbeSMauro Carvalho Chehab 40610ffebbeSMauro Carvalho ChehabSame as above except to inject page allocation failure instead of slab 40710ffebbeSMauro Carvalho Chehaballocation failure:: 40810ffebbeSMauro Carvalho Chehab 40910ffebbeSMauro Carvalho Chehab # env FAILCMD_TYPE=fail_page_alloc \ 41010ffebbeSMauro Carvalho Chehab ./tools/testing/fault-injection/failcmd.sh --times=100 \ 41110ffebbeSMauro Carvalho Chehab -- make -C tools/testing/selftests/ run_tests 41210ffebbeSMauro Carvalho Chehab 41310ffebbeSMauro Carvalho ChehabSystematic faults using fail-nth 41410ffebbeSMauro Carvalho Chehab--------------------------------- 41510ffebbeSMauro Carvalho Chehab 41610ffebbeSMauro Carvalho ChehabThe following code systematically faults 0-th, 1-st, 2-nd and so on 41710ffebbeSMauro Carvalho Chehabcapabilities in the socketpair() system call:: 41810ffebbeSMauro Carvalho Chehab 41910ffebbeSMauro Carvalho Chehab #include <sys/types.h> 42010ffebbeSMauro Carvalho Chehab #include <sys/stat.h> 42110ffebbeSMauro Carvalho Chehab #include <sys/socket.h> 42210ffebbeSMauro Carvalho Chehab #include <sys/syscall.h> 42310ffebbeSMauro Carvalho Chehab #include <fcntl.h> 42410ffebbeSMauro Carvalho Chehab #include <unistd.h> 42510ffebbeSMauro Carvalho Chehab #include <string.h> 42610ffebbeSMauro Carvalho Chehab #include <stdlib.h> 42710ffebbeSMauro Carvalho Chehab #include <stdio.h> 42810ffebbeSMauro Carvalho Chehab #include <errno.h> 42910ffebbeSMauro Carvalho Chehab 43010ffebbeSMauro Carvalho Chehab int main() 43110ffebbeSMauro Carvalho Chehab { 43210ffebbeSMauro Carvalho Chehab int i, err, res, fail_nth, fds[2]; 43310ffebbeSMauro Carvalho Chehab char buf[128]; 43410ffebbeSMauro Carvalho Chehab 43510ffebbeSMauro Carvalho Chehab system("echo N > /sys/kernel/debug/failslab/ignore-gfp-wait"); 43610ffebbeSMauro Carvalho Chehab sprintf(buf, "/proc/self/task/%ld/fail-nth", syscall(SYS_gettid)); 43710ffebbeSMauro Carvalho Chehab fail_nth = open(buf, O_RDWR); 43810ffebbeSMauro Carvalho Chehab for (i = 1;; i++) { 43910ffebbeSMauro Carvalho Chehab sprintf(buf, "%d", i); 44010ffebbeSMauro Carvalho Chehab write(fail_nth, buf, strlen(buf)); 44110ffebbeSMauro Carvalho Chehab res = socketpair(AF_LOCAL, SOCK_STREAM, 0, fds); 44210ffebbeSMauro Carvalho Chehab err = errno; 44310ffebbeSMauro Carvalho Chehab pread(fail_nth, buf, sizeof(buf), 0); 44410ffebbeSMauro Carvalho Chehab if (res == 0) { 44510ffebbeSMauro Carvalho Chehab close(fds[0]); 44610ffebbeSMauro Carvalho Chehab close(fds[1]); 44710ffebbeSMauro Carvalho Chehab } 44810ffebbeSMauro Carvalho Chehab printf("%d-th fault %c: res=%d/%d\n", i, atoi(buf) ? 'N' : 'Y', 44910ffebbeSMauro Carvalho Chehab res, err); 45010ffebbeSMauro Carvalho Chehab if (atoi(buf)) 45110ffebbeSMauro Carvalho Chehab break; 45210ffebbeSMauro Carvalho Chehab } 45310ffebbeSMauro Carvalho Chehab return 0; 45410ffebbeSMauro Carvalho Chehab } 45510ffebbeSMauro Carvalho Chehab 45610ffebbeSMauro Carvalho ChehabAn example output:: 45710ffebbeSMauro Carvalho Chehab 45810ffebbeSMauro Carvalho Chehab 1-th fault Y: res=-1/23 45910ffebbeSMauro Carvalho Chehab 2-th fault Y: res=-1/23 46010ffebbeSMauro Carvalho Chehab 3-th fault Y: res=-1/12 46110ffebbeSMauro Carvalho Chehab 4-th fault Y: res=-1/12 46210ffebbeSMauro Carvalho Chehab 5-th fault Y: res=-1/23 46310ffebbeSMauro Carvalho Chehab 6-th fault Y: res=-1/23 46410ffebbeSMauro Carvalho Chehab 7-th fault Y: res=-1/23 46510ffebbeSMauro Carvalho Chehab 8-th fault Y: res=-1/12 46610ffebbeSMauro Carvalho Chehab 9-th fault Y: res=-1/12 46710ffebbeSMauro Carvalho Chehab 10-th fault Y: res=-1/12 46810ffebbeSMauro Carvalho Chehab 11-th fault Y: res=-1/12 46910ffebbeSMauro Carvalho Chehab 12-th fault Y: res=-1/12 47010ffebbeSMauro Carvalho Chehab 13-th fault Y: res=-1/12 47110ffebbeSMauro Carvalho Chehab 14-th fault Y: res=-1/12 47210ffebbeSMauro Carvalho Chehab 15-th fault Y: res=-1/12 47310ffebbeSMauro Carvalho Chehab 16-th fault N: res=0/12 474