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RDMA/uverbs: Fix RCU annotation for radix slot deference

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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: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
This commit is contained in:
Jason Gunthorpe 2018-09-28 16:28:02 -06:00
parent 914e5d7d46
commit e73798f20e
1 changed files with 3 additions and 6 deletions
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9
drivers/infiniband/core/uverbs_ioctl.c
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@ -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);