From: Jason Gunthorpe <jgg@nvidia.com> stable inclusion from stable-v6.6.120 commit c0acdee513239e1d6e1b490f56be0e6837dfd162 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/13395 CVE: CVE-2025-71084 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit 57f3cb6c84159d12ba343574df2115fb18dd83ca upstream. If the CM ID is destroyed while the CM event for multicast creating is still queued the cancel_work_sync() will prevent the work from running which also prevents destroying the ah_attr. This leaks a refcount and triggers a WARN: GID entry ref leak for dev syz1 index 2 ref=573 WARNING: CPU: 1 PID: 655 at drivers/infiniband/core/cache.c:809 release_gid_table drivers/infiniband/core/cache.c:806 [inline] WARNING: CPU: 1 PID: 655 at drivers/infiniband/core/cache.c:809 gid_table_release_one+0x284/0x3cc drivers/infiniband/core/cache.c:886 Destroy the ah_attr after canceling the work, it is safe to call this twice. Link: https://patch.msgid.link/r/0-v1-4285d070a6b2+20a-rdma_mc_gid_leak_syz_jgg@nv... Cc: stable@vger.kernel.org Fixes: fe454dc31e84 ("RDMA/ucma: Fix use-after-free bug in ucma_create_uevent") Reported-by: syzbot+b0da83a6c0e2e2bddbd4@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/68232e7b.050a0220.f2294.09f6.GAE@google.com Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Liu Kai <liukai284@huawei.com> --- drivers/infiniband/core/cma.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c index a5ceae2e075a..7db79ff3fa06 100644 --- a/drivers/infiniband/core/cma.c +++ b/drivers/infiniband/core/cma.c @@ -1993,6 +1993,7 @@ static void destroy_mc(struct rdma_id_private *id_priv, ib_sa_free_multicast(mc->sa_mc); if (rdma_protocol_roce(id_priv->id.device, id_priv->id.port_num)) { + struct rdma_cm_event *event = &mc->iboe_join.event; struct rdma_dev_addr *dev_addr = &id_priv->id.route.addr.dev_addr; struct net_device *ndev = NULL; @@ -2015,6 +2016,8 @@ static void destroy_mc(struct rdma_id_private *id_priv, dev_put(ndev); cancel_work_sync(&mc->iboe_join.work); + if (event->event == RDMA_CM_EVENT_MULTICAST_JOIN) + rdma_destroy_ah_attr(&event->param.ud.ah_attr); } kfree(mc); } -- 2.34.1