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Francois Dugast
91b2c42c21
The kernel fault injection infrastructure is used to test proper error
handling during probe. The return code of the functions using
ALLOW_ERROR_INJECTION() can be conditionnally modified at runtime by
tuning some debugfs entries. This requires CONFIG_FUNCTION_ERROR_INJECTION
(among others).
One way to use fault injection at probe time by making each of those
functions fail one at a time is:
FAILTYPE=fail_function
DEVICE="0000:00:08.0" # depends on the system
ERRNO=-12 # -ENOMEM, can depend on the function
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
modprobe xe
echo $DEVICE > /sys/bus/pci/drivers/xe/unbind
grep -oP "^.* \[xe\]" /sys/kernel/debug/$FAILTYPE/injectable | \
cut -d ' ' -f 1 | while read -r FUNCTION ; do
echo "Injecting fault in $FUNCTION"
echo "" > /sys/kernel/debug/$FAILTYPE/inject
echo $FUNCTION > /sys/kernel/debug/$FAILTYPE/inject
printf %#x $ERRNO > /sys/kernel/debug/$FAILTYPE/$FUNCTION/retval
echo $DEVICE > /sys/bus/pci/drivers/xe/bind
done
rmmod xe
It will also be integrated into IGT for systematic execution by CI.
v2: Wrappers are not needed in the cases covered by this patch, so
remove them and use ALLOW_ERROR_INJECTION() directly.
v3: Document the use of fault injection at probe time in xe_pci_probe
and refer to it where ALLOW_ERROR_INJECTION() is used.
Signed-off-by: Francois Dugast <francois.dugast@intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240927151207.399354-1-francois.dugast@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.