Commit e73798f2 authored by Jason Gunthorpe's avatar Jason Gunthorpe
Browse files

RDMA/uverbs: Fix RCU annotation for radix slot deference 



The uapi radix tree is a write-once data structure protected by kref.
Once we get to the ioctl() fop it is not possible for anything else
to be writing to it, so the access should use rcu_dereference_protected.

Reported-by: default avatarMatthew Wilcox <willy@infradead.org>
Signed-off-by: default avatarJason Gunthorpe <jgg@mellanox.com>
parent 914e5d7d

drivers/infiniband/core/uverbs_ioctl.c

+3 −6
Original line number Diff line number Diff line
@@ -386,8 +386,7 @@ static int uverbs_set_attr(struct bundle_priv *pbundle, 
			return -EPROTONOSUPPORT;

		return 0;

	}

	attr = srcu_dereference(

		*slot, &pbundle->bundle.ufile->device->disassociate_srcu);

	attr = rcu_dereference_protected(*slot, true);



	/* Reject duplicate attributes from user-space */

	if (test_bit(attr_bkey, pbundle->bundle.attr_present))
@@ -498,9 +497,7 @@ static int bundle_destroy(struct bundle_priv *pbundle, bool commit) 
		if (WARN_ON(!slot))

			continue;



		attr_uapi = srcu_dereference(

			*slot,

			&pbundle->bundle.ufile->device->disassociate_srcu);

		attr_uapi = rcu_dereference_protected(*slot, true);



		if (attr_uapi->spec.type == UVERBS_ATTR_TYPE_IDRS_ARRAY) {

			current_ret = uverbs_free_idrs_array(
@@ -542,7 +539,7 @@ static int ib_uverbs_cmd_verbs(struct ib_uverbs_file *ufile, 
			uapi_key_ioctl_method(hdr->method_id));

	if (unlikely(!slot))

		return -EPROTONOSUPPORT;

	method_elm = srcu_dereference(*slot, &ufile->device->disassociate_srcu);

	method_elm = rcu_dereference_protected(*slot, true);



	if (!method_elm->use_stack) {

		pbundle = kmalloc(method_elm->bundle_size, GFP_KERNEL);

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