fault-inject-debugfs kernel module provides some debugfs entries for runtime
configuration of fault-injection capabilities.
-- /debug/fail*/probability:
+- /sys/kernel/debug/fail*/probability:
likelihood of failure injection, in percent.
Format: <percent>
Note that one-failure-per-hundred is a very high error rate
for some testcases. Consider setting probability=100 and configure
- /debug/fail*/interval for such testcases.
+ /sys/kernel/debug/fail*/interval for such testcases.
-- /debug/fail*/interval:
+- /sys/kernel/debug/fail*/interval:
specifies the interval between failures, for calls to
should_fail() that pass all the other tests.
Note that if you enable this, by setting interval>1, you will
probably want to set probability=100.
-- /debug/fail*/times:
+- /sys/kernel/debug/fail*/times:
specifies how many times failures may happen at most.
A value of -1 means "no limit".
-- /debug/fail*/space:
+- /sys/kernel/debug/fail*/space:
specifies an initial resource "budget", decremented by "size"
on each call to should_fail(,size). Failure injection is
suppressed until "space" reaches zero.
-- /debug/fail*/verbose
+- /sys/kernel/debug/fail*/verbose
Format: { 0 | 1 | 2 }
specifies the verbosity of the messages when failure is
log line per failure; '2' will print a call trace too -- useful
to debug the problems revealed by fault injection.
-- /debug/fail*/task-filter:
+- /sys/kernel/debug/fail*/task-filter:
Format: { 'Y' | 'N' }
A value of 'N' disables filtering by process (default).
Any positive value limits failures to only processes indicated by
/proc/<pid>/make-it-fail==1.
-- /debug/fail*/require-start:
-- /debug/fail*/require-end:
-- /debug/fail*/reject-start:
-- /debug/fail*/reject-end:
+- /sys/kernel/debug/fail*/require-start:
+- /sys/kernel/debug/fail*/require-end:
+- /sys/kernel/debug/fail*/reject-start:
+- /sys/kernel/debug/fail*/reject-end:
specifies the range of virtual addresses tested during
stacktrace walking. Failure is injected only if some caller
Default required range is [0,ULONG_MAX) (whole of virtual address space).
Default rejected range is [0,0).
-- /debug/fail*/stacktrace-depth:
+- /sys/kernel/debug/fail*/stacktrace-depth:
specifies the maximum stacktrace depth walked during search
for a caller within [require-start,require-end) OR
[reject-start,reject-end).
-- /debug/fail_page_alloc/ignore-gfp-highmem:
+- /sys/kernel/debug/fail_page_alloc/ignore-gfp-highmem:
Format: { 'Y' | 'N' }
default is 'N', setting it to 'Y' won't inject failures into
highmem/user allocations.
-- /debug/failslab/ignore-gfp-wait:
-- /debug/fail_page_alloc/ignore-gfp-wait:
+- /sys/kernel/debug/failslab/ignore-gfp-wait:
+- /sys/kernel/debug/fail_page_alloc/ignore-gfp-wait:
Format: { 'Y' | 'N' }
default is 'N', setting it to 'Y' will inject failures
only into non-sleep allocations (GFP_ATOMIC allocations).
+- /sys/kernel/debug/fail_page_alloc/min-order:
+
+ specifies the minimum page allocation order to be injected
+ failures.
+
o Boot option
In order to inject faults while debugfs is not available (early boot time),
Application Examples
--------------------
-o inject slab allocation failures into module init/cleanup code
+o Inject slab allocation failures into module init/exit code
-------------------------------------------------------------------------------
#!/bin/bash
-FAILCMD=Documentation/fault-injection/failcmd.sh
-BLACKLIST="root_plug evbug"
-
-FAILNAME=failslab
-echo Y > /debug/$FAILNAME/task-filter
-echo 10 > /debug/$FAILNAME/probability
-echo 100 > /debug/$FAILNAME/interval
-echo -1 > /debug/$FAILNAME/times
-echo 2 > /debug/$FAILNAME/verbose
-echo 1 > /debug/$FAILNAME/ignore-gfp-wait
+FAILTYPE=failslab
+echo Y > /sys/kernel/debug/$FAILTYPE/task-filter
+echo 10 > /sys/kernel/debug/$FAILTYPE/probability
+echo 100 > /sys/kernel/debug/$FAILTYPE/interval
+echo -1 > /sys/kernel/debug/$FAILTYPE/times
+echo 0 > /sys/kernel/debug/$FAILTYPE/space
+echo 2 > /sys/kernel/debug/$FAILTYPE/verbose
+echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-wait
-blacklist()
+faulty_system()
{
- echo $BLACKLIST | grep $1 > /dev/null 2>&1
+ bash -c "echo 1 > /proc/self/make-it-fail && exec $*"
}
-oops()
-{
- dmesg | grep BUG > /dev/null 2>&1
-}
+if [ $# -eq 0 ]
+then
+ echo "Usage: $0 modulename [ modulename ... ]"
+ exit 1
+fi
+
+for m in $*
+do
+ echo inserting $m...
+ faulty_system modprobe $m
-find /lib/modules/`uname -r` -name '*.ko' -exec basename {} .ko \; |
- while read i
- do
- oops && exit 1
-
- if ! blacklist $i
- then
- echo inserting $i...
- bash $FAILCMD modprobe $i
- fi
- done
-
-lsmod | awk '{ if ($3 == 0) { print $1 } }' |
- while read i
- do
- oops && exit 1
-
- if ! blacklist $i
- then
- echo removing $i...
- bash $FAILCMD modprobe -r $i
- fi
- done
+ echo removing $m...
+ faulty_system modprobe -r $m
+done
------------------------------------------------------------------------------
-o inject slab allocation failures only for a specific module
+o Inject page allocation failures only for a specific module
-------------------------------------------------------------------------------
#!/bin/bash
-FAILMOD=Documentation/fault-injection/failmodule.sh
+FAILTYPE=fail_page_alloc
+module=$1
-echo injecting errors into the module $1...
+if [ -z $module ]
+then
+ echo "Usage: $0 <modulename>"
+ exit 1
+fi
-modprobe $1
-bash $FAILMOD failslab $1 10
-echo 25 > /debug/failslab/probability
+modprobe $module
-------------------------------------------------------------------------------
+if [ ! -d /sys/module/$module/sections ]
+then
+ echo Module $module is not loaded
+ exit 1
+fi
+
+cat /sys/module/$module/sections/.text > /sys/kernel/debug/$FAILTYPE/require-start
+cat /sys/module/$module/sections/.data > /sys/kernel/debug/$FAILTYPE/require-end
+
+echo N > /sys/kernel/debug/$FAILTYPE/task-filter
+echo 10 > /sys/kernel/debug/$FAILTYPE/probability
+echo 100 > /sys/kernel/debug/$FAILTYPE/interval
+echo -1 > /sys/kernel/debug/$FAILTYPE/times
+echo 0 > /sys/kernel/debug/$FAILTYPE/space
+echo 2 > /sys/kernel/debug/$FAILTYPE/verbose
+echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-wait
+echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-highmem
+echo 10 > /sys/kernel/debug/$FAILTYPE/stacktrace-depth
+
+trap "echo 0 > /sys/kernel/debug/$FAILTYPE/probability" SIGINT SIGTERM EXIT
+
+echo "Injecting errors into the module $module... (interrupt to stop)"
+sleep 1000000
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