The pointer to an AFU in the adapter's list of AFUs can be null
if we're in the process of removing AFUs. The afu_list_lock
doesn't guard against this.
Say we have 2 slices, and we're in the process of removing cxl.
- We remove the AFUs in order (see cxl_remove). In cxl_remove_afu
for AFU 0, we take the lock, set adapter->afu[0] = NULL, and
release the lock.
- Then we get an slbia. In cxl_slbia we take the lock, and set
afu = adapter->afu[0], which is NULL.
- Therefore our attempt to check afu->enabled will blow up.
Therefore, check if afu is a null pointer before dereferencing it.
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Axtens <dja@axtens.net>
Acked-by: Michael Neuling <mikey@neuling.org>
Acked-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2c069a118f