Daniel Axtens 4a0c377cda cxl: Check if afu is not null in cxl_slbia ...

commit 2c069a118f upstream.

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.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2015-08-10 12:21:50 -07:00

5.4 KiB

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