• Hon Ching (Vicky) Lo's avatar
    tpm: Fix NULL return in tpm_ibmvtpm_get_desired_dma · 84eb186b
    Hon Ching (Vicky) Lo authored
    There was an oops in tpm_ibmvtpm_get_desired_dma, which caused
    kernel panic during boot when vTPM is enabled in Power partition
    configured in AMS mode.
    
    vio_bus_probe calls vio_cmo_bus_probe which calls
    tpm_ibmvtpm_get_desired_dma to get the size needed for DMA allocation.
    The problem is, vio_cmo_bus_probe is called before calling probe, which
    for vtpm is tpm_ibmvtpm_probe and it's this function that initializes
    and sets up vtpm's CRQ and gets required data values.  Therefore,
    since this has not yet been done, NULL is returned in attempt to get
    the size for DMA allocation.
    
    We added a NULL check.  In addition, a default buffer size will
    be set when NULL is returned.
    
    Cc: <stable@vger.kernel.org>
    Signed-off-by: default avatarHon Ching (Vicky) Lo <honclo@linux.vnet.ibm.com>
    Signed-off-by: default avatarPeter Huewe <peterhuewe@gmx.de>
    84eb186b
tpm_ibmvtpm.c 15.3 KB