• Akinobu Mita's avatar
    cpu: rewrite cpu-notifier-error-inject module · f5a9f52e
    Akinobu Mita authored
    Rewrite existing cpu-notifier-error-inject module to use debugfs based new
    framework.
    
    This change removes cpu_up_prepare_error and cpu_down_prepare_error module
    parameters which were used to specify error code to be injected.  We could
    keep these module parameters for backward compatibility by module_param_cb
    but it seems overkill for this module.
    
    This provides the ability to inject artifical errors to CPU notifier chain
    callbacks.  It is controlled through debugfs interface under
    /sys/kernel/debug/notifier-error-inject/cpu
    
    If the notifier call chain should be failed with some events notified,
    write the error code to "actions/<notifier event>/error".
    
    Example1: inject CPU offline error (-1 == -EPERM)
    
    	# cd /sys/kernel/debug/notifier-error-inject/cpu
    	# echo -1 > actions/CPU_DOWN_PREPARE/error
    	# echo 0 > /sys/devices/system/cpu/cpu1/online
    	bash: echo: write error: Operation not permitted
    
    Example2: inject CPU online error (-2 == -ENOENT)
    
    	# cd /sys/kernel/debug/notifier-error-inject/cpu
    	# echo -2 > actions/CPU_UP_PREPARE/error
    	# echo 1 > /sys/devices/system/cpu/cpu1/online
    	bash: echo: write error: No such file or directory
    Signed-off-by: 's avatarAkinobu Mita <akinobu.mita@gmail.com>
    Cc: Pavel Machek <pavel@ucw.cz>
    Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
    Cc: Greg KH <greg@kroah.com>
    Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
    Cc: Paul Mackerras <paulus@samba.org>
    Cc: Michael Ellerman <michael@ellerman.id.au>
    Cc: Dave Jones <davej@redhat.com>
    Signed-off-by: 's avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: 's avatarLinus Torvalds <torvalds@linux-foundation.org>
    f5a9f52e
cpu-notifier-error-inject.c 1.18 KB