cxl: Check if afu is not null in cxl_slbia

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: [email protected]
Signed-off-by: Daniel Axtens <[email protected]>
Acked-by: Michael Neuling <[email protected]>
Acked-by: Ian Munsie <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>

0 files changed, 0 insertions, 0 deletions