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: 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>
diff --git a/drivers/misc/cxl/main.c b/drivers/misc/cxl/main.c
index 833348e..4a164ab 100644
--- a/drivers/misc/cxl/main.c
+++ b/drivers/misc/cxl/main.c
@@ -73,7 +73,7 @@
spin_lock(&adapter->afu_list_lock);
for (slice = 0; slice < adapter->slices; slice++) {
afu = adapter->afu[slice];
- if (!afu->enabled)
+ if (!afu || !afu->enabled)
continue;
rcu_read_lock();
idr_for_each_entry(&afu->contexts_idr, ctx, id)
