• Jun'ichi Nomura's avatar
    dm: table detect io beyond device · 512875bd
    Jun'ichi Nomura authored
    This patch fixes a panic on shrinking a DM device if there is
    outstanding I/O to the part of the device that is being removed.
    (Normally this doesn't happen - a filesystem would be resized first,
    for example.)
    The bug is that __clone_and_map() assumes dm_table_find_target()
    always returns a valid pointer.  It may fail if a bio arrives from the
    block layer but its target sector is no longer included in the DM
    This patch appends an empty entry to table->targets[] which will
    be returned by a lookup beyond the end of the device.
    After calling dm_table_find_target(), __clone_and_map() and target_message()
    check for this condition using
    Sample test script to trigger oops:
dm.h 4.93 KB