From e73798f20ecb35f7d6c672d48d6b9da57c8cbf64 Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Fri, 28 Sep 2018 16:28:02 -0600 Subject: [PATCH] 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: Matthew Wilcox Signed-off-by: Jason Gunthorpe --- drivers/infiniband/core/uverbs_ioctl.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/drivers/infiniband/core/uverbs_ioctl.c b/drivers/infiniband/core/uverbs_ioctl.c index 0e95a5888274..b0e493e8d860 100644 --- a/drivers/infiniband/core/uverbs_ioctl.c +++ b/drivers/infiniband/core/uverbs_ioctl.c @@ -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);