From 9fc6a635220fdd8a0a29de0a985a4a0c3a6890fd Mon Sep 17 00:00:00 2001 From: Hans Petter Selasky Date: Tue, 21 Jun 2022 11:23:55 +0200 Subject: [PATCH] ibcore: Fix a race with disassociate and exit_mmap() If uverbs_user_mmap_disassociate() is called while the mmap is concurrently doing exit_mmap then the ordering of the rdma_user_mmap_entry_put() is not reliable. The put must be done before uvers_user_mmap_disassociate() returns, otherwise there can be a use after free on the ucontext, and a left over entry in the xarray. If the put is not done here then it is done during rdma_umap_close() later. Add the missing put to the error exit path. Linux commit: 39c011a538272589b9eb02ff1228af528522a22c PR: 264473 MFC after: 3 days Sponsored by: NVIDIA Networking --- sys/ofed/drivers/infiniband/core/ib_uverbs_main.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/sys/ofed/drivers/infiniband/core/ib_uverbs_main.c b/sys/ofed/drivers/infiniband/core/ib_uverbs_main.c index 1661458c689b..432d46760ecb 100644 --- a/sys/ofed/drivers/infiniband/core/ib_uverbs_main.c +++ b/sys/ofed/drivers/infiniband/core/ib_uverbs_main.c @@ -778,6 +778,10 @@ void uverbs_user_mmap_disassociate(struct ib_uverbs_file *ufile) ret = mmget_not_zero(mm); if (!ret) { list_del_init(&priv->list); + if (priv->entry) { + rdma_user_mmap_entry_put(priv->entry); + priv->entry = NULL; + } mm = NULL; continue; }