• Jonathan Brassow's avatar
    Prevent DM RAID from loading bitmap twice. · 34f8ac6d
    Jonathan Brassow authored
    The life cycle of a device-mapper target is:
    1) create
    2) resume
    3) suspend
    *) possibly repeat from 2
    4) destroy
    The dm-raid target is unconditionally calling MD's bitmap_load function upon
    every resume.  If steps 2 & 3 above are repeated, bitmap_load is called
    multiple times.  It is only written to be called once; otherwise, it allocates
    new memory for the bitmap (without freeing the old) and incrementing the number
    of pages it thinks it has without zeroing first.  This ultimately leads to
    access beyond allocated memory and lost memory.
    Simply avoiding the bitmap_load call upon resume is not sufficient.  If the
    target was suspended while the initial recovery was only partially complete,
    it needs to be restarted when the target is resumed.  This is why
    'md_wakeup_thread' is called before issuing the 'mddev_resume'.
    Signed-off-by: default avatarJonathan Brassow <jbrassow@redhat.com>
    Signed-off-by: default avatarNeilBrown <neilb@suse.de>