From: Jason Gunthorpe Date: Wed, 15 Jan 2020 20:20:44 +0000 (+0000) Subject: RDMA/core: Ensure that rdma_user_mmap_entry_remove() is a fence X-Git-Tag: v5.6-rc1~94^2~15 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=6b3712c0246ca7b2b8fa05eab2362cf267410f7e;p=thirdparty%2Flinux.git RDMA/core: Ensure that rdma_user_mmap_entry_remove() is a fence The set of entry->driver_removed is missing locking, protect it with xa_lock() which is held by the only reader. Otherwise readers may continue to see driver_removed = false after rdma_user_mmap_entry_remove() returns and may continue to try and establish new mmaps. Fixes: 3411f9f01b76 ("RDMA/core: Create mmap database and cookie helper functions") Link: https://lore.kernel.org/r/20200115202041.GA17199@ziepe.ca Reviewed-by: Gal Pressman Acked-by: Michal Kalderon Signed-off-by: Jason Gunthorpe --- diff --git a/drivers/infiniband/core/ib_core_uverbs.c b/drivers/infiniband/core/ib_core_uverbs.c index b7cb59844ece4..b51bd7087a881 100644 --- a/drivers/infiniband/core/ib_core_uverbs.c +++ b/drivers/infiniband/core/ib_core_uverbs.c @@ -232,7 +232,9 @@ void rdma_user_mmap_entry_remove(struct rdma_user_mmap_entry *entry) if (!entry) return; + xa_lock(&entry->ucontext->mmap_xa); entry->driver_removed = true; + xa_unlock(&entry->ucontext->mmap_xa); kref_put(&entry->ref, rdma_user_mmap_entry_free); } EXPORT_SYMBOL(rdma_user_mmap_entry_remove);