2018-01-13 2:56 GMT+09:00 Masami Hiramatsu <mhira...@kernel.org>: > Support in-kernel fault-injection framework via debugfs. > This allows you to inject a conditional error to specified > function using debugfs interfaces. > > Here is the result of test script described in > Documentation/fault-injection/fault-injection.txt > > =========== > # ./test_fail_function.sh > 1+0 records in > 1+0 records out > 1048576 bytes (1.0 MB, 1.0 MiB) copied, 0.0227404 s, 46.1 MB/s > btrfs-progs v4.4 > See http://btrfs.wiki.kernel.org for more information. > > Label: (null) > UUID: bfa96010-12e9-4360-aed0-42eec7af5798 > Node size: 16384 > Sector size: 4096 > Filesystem size: 1001.00MiB > Block group profiles: > Data: single 8.00MiB > Metadata: DUP 58.00MiB > System: DUP 12.00MiB > SSD detected: no > Incompat features: extref, skinny-metadata > Number of devices: 1 > Devices: > ID SIZE PATH > 1 1001.00MiB /dev/loop2 > > mount: mount /dev/loop2 on /opt/tmpmnt failed: Cannot allocate memory > SUCCESS! > =========== > > > Signed-off-by: Masami Hiramatsu <mhira...@kernel.org> > Reviewed-by: Josef Bacik <jba...@fb.com> > --- > Changes in v3: > - Check and adjust error value for each target function > - Clear kporbe flag for reuse > - Add more documents and example > Changes in v5: > - Support multi-function error injection > --- > Documentation/fault-injection/fault-injection.txt | 68 ++++ > kernel/Makefile | 1 > kernel/fail_function.c | 349 > +++++++++++++++++++++ > lib/Kconfig.debug | 10 + > 4 files changed, 428 insertions(+) > create mode 100644 kernel/fail_function.c > > diff --git a/Documentation/fault-injection/fault-injection.txt > b/Documentation/fault-injection/fault-injection.txt > index 918972babcd8..f4a32463ca48 100644 > --- a/Documentation/fault-injection/fault-injection.txt > +++ b/Documentation/fault-injection/fault-injection.txt > @@ -30,6 +30,12 @@ o fail_mmc_request > injects MMC data errors on devices permitted by setting > debugfs entries under /sys/kernel/debug/mmc0/fail_mmc_request > > +o fail_function > + > + injects error return on specific functions, which are marked by > + ALLOW_ERROR_INJECTION() macro, by setting debugfs entries > + under /sys/kernel/debug/fail_function. No boot option supported. > + > Configure fault-injection capabilities behavior > ----------------------------------------------- > > @@ -123,6 +129,29 @@ configuration of fault-injection capabilities. > default is 'N', setting it to 'Y' will disable failure injections > when dealing with private (address space) futexes. > > +- /sys/kernel/debug/fail_function/inject: > + > + Format: { 'function-name' | '!function-name' | '' } > + specifies the target function of error injection by name. > + If the function name leads '!' prefix, given function is > + removed from injection list. If nothing specified ('') > + injection list is cleared. > + > +- /sys/kernel/debug/fail_function/injectable: > + > + (read only) shows error injectable functions and what type of > + error values can be specified. The error type will be one of > + below; > + - NULL: retval must be 0. > + - ERRNO: retval must be -1 to -MAX_ERRNO (-4096). > + - ERR_NULL: retval must be 0 or -1 to -MAX_ERRNO (-4096). > + > +- /sys/kernel/debug/fail_function/<functiuon-name>/retval: > + > + specifies the "error" return value to inject to the given > + function for given function. This will be created when > + user specifies new injection entry. > + > o Boot option > > In order to inject faults while debugfs is not available (early boot time), > @@ -268,6 +297,45 @@ trap "echo 0 > /sys/kernel/debug/$FAILTYPE/probability" > SIGINT SIGTERM EXIT > echo "Injecting errors into the module $module... (interrupt to stop)" > sleep 1000000 > > +------------------------------------------------------------------------------ > + > +o Inject open_ctree error while btrfs mount > + > +#!/bin/bash > + > +rm -f testfile.img > +dd if=/dev/zero of=testfile.img bs=1M seek=1000 count=1 > +DEVICE=$(losetup --show -f testfile.img) > +mkfs.btrfs -f $DEVICE > +mkdir -p tmpmnt > + > +FAILTYPE=fail_function > +FAILFUNC=open_ctree > +echo $FAILFUNC > /sys/kernel/debug/$FAILTYPE/inject > +echo -12 > /sys/kernel/debug/$FAILTYPE/$FAILFUNC/retval > +echo N > /sys/kernel/debug/$FAILTYPE/task-filter > +echo 100 > /sys/kernel/debug/$FAILTYPE/probability > +echo 0 > /sys/kernel/debug/$FAILTYPE/interval > +echo -1 > /sys/kernel/debug/$FAILTYPE/times > +echo 0 > /sys/kernel/debug/$FAILTYPE/space > +echo 1 > /sys/kernel/debug/$FAILTYPE/verbose
I expected that the fault_attr is created for each target function. (i.e. /sys/kernel/debug/fail_function/<func>/ directory contains not only 'retval', but also 'probability', 'interval', ...) Or is there any good reason to share a single fault_attr for all error injected functions?
