From 8b90e701342275f414e36e7421c502237df241ad Mon Sep 17 00:00:00 2001 From: Patrisious Haddad Date: Mon, 13 Jul 2026 18:38:07 +0300 Subject: [PATCH] RDMA/core: Fix potential use after free in ib_dealloc_pd_user() When accessing a PD via the netlink path the only synchronization mechanism for the said PD is rdma_restrack_get(). Currently, rdma_restrack_del() is invoked at the end of ib_dealloc_pd_user(), which is too late, since by that point vendor-specific resources associated with the PD might already be freed. This can leave a short window where the PD remains accessible through restrack, leading to a potential use-after-free. Fix this by moving the rdma_restrack_begin_del() call to the start of ib_dealloc_pd_user(), ensuring that the PD is removed from restrack before its internal resources are released. This guarantees that no new users hold references to a PD that is in the process of destruction. In addition, this change preserves the intended inverted order between create and destroy routines: resources are added to restrack at the end of successful creation, and hence shall be removed from the restrack first thing during the destruction flow, which keeps the lifecycle management consistent and predictable. Fixes: 91a7c58fce06 ("RDMA: Restore ability to fail on PD deallocate") Signed-off-by: Patrisious Haddad Reviewed-by: Michael Guralnik Signed-off-by: Edward Srouji Link: https://patch.msgid.link/20260713-restrack-uaf-fix-resub-v2-8-bbe8bb270d51@nvidia.com Signed-off-by: Leon Romanovsky --- drivers/infiniband/core/verbs.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/infiniband/core/verbs.c b/drivers/infiniband/core/verbs.c index bfbc25dee95d..f86e6f30b1df 100644 --- a/drivers/infiniband/core/verbs.c +++ b/drivers/infiniband/core/verbs.c @@ -392,6 +392,7 @@ int ib_dealloc_pd_user(struct ib_pd *pd, struct ib_udata *udata) { int ret; + rdma_restrack_begin_del(&pd->res); if (pd->__internal_mr) { ret = pd->device->ops.dereg_mr(pd->__internal_mr, NULL); WARN_ON(ret); @@ -399,10 +400,12 @@ int ib_dealloc_pd_user(struct ib_pd *pd, struct ib_udata *udata) } ret = pd->device->ops.dealloc_pd(pd, udata); - if (ret) + if (ret) { + rdma_restrack_abort_del(&pd->res); return ret; + } - rdma_restrack_del(&pd->res); + rdma_restrack_commit_del(&pd->res); kfree(pd); return ret; }