cxl/region: Fix decoder allocation crash

When an intermediate port's decoders have been exhausted by existing
regions, and creating a new region with the port in question in it's
hierarchical path is attempted, cxl_port_attach_region() fails to find a
port decoder (as would be expected), and drops into the failure / cleanup
path.

However, during cleanup of the region reference, a sanity check attempts
to dereference the decoder, which in the above case didn't exist. This
causes a NULL pointer dereference BUG.

To fix this, refactor the decoder allocation and de-allocation into
helper routines, and in this 'free' routine, check that the decoder,
@cxld, is valid before attempting any operations on it.

Cc: <[email protected]>
Suggested-by: Dan Williams <[email protected]>
Signed-off-by: Vishal Verma <[email protected]>
Reviewed-by: Dave Jiang <[email protected]>
Fixes: 384e624bb211 ("cxl/region: Attach endpoint decoders")
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Dan Williams <[email protected]>

0 files changed, 0 insertions, 0 deletions