From 5211fed41d7ec90e9ab7239dc4bffffe4d0b2b62 Mon Sep 17 00:00:00 2001 From: Guixin Liu Date: Wed, 16 Sep 2026 19:42:54 +0800 Subject: [PATCH] nvmet: copy the hostid into the ctrl before creating PR pc_refs Commit 6202783184bf ("nvmet: Improve nvmet_alloc_ctrl() interface and implementation") added a second uuid_copy() of args->hostid near the end of nvmet_alloc_ctrl(), and commit 7b658153f1b8 ("nvmet: Remove duplicate uuid_copy") removed the original copy that sat before nvmet_ctrl_init_pr() instead of the new one. Since then nvmet_ctrl_init_pr() snapshots ctrl->hostid into the per-controller per-namespace reservation refs while the uuid_copy() from the connect data runs later, after the controller is published. The ctrl is allocated with kzalloc(), so every pc_ref created on this path stores the nil UUID. pc_ref->hostid has a single consumer: nvmet_pr_set_ctrl_to_abort() matches it against the preempted registrant's hostid to kill and drain the victim's in-flight I/O for Preempt and Abort. The match can never hit with the nil UUID, so whenever a namespace with reservations enabled exists before a host connects, which includes every reconnect, Preempt and Abort silently degrades into a plain Preempt: the preempting host sees success while the victim's in-flight I/O is still in the air. Copy the hostid where the rest of the connect data is consumed, before the controller is published and before nvmet_ctrl_init_pr() takes its snapshot. Fixes: 7b658153f1b8 ("nvmet: Remove duplicate uuid_copy") Cc: stable@vger.kernel.org Reviewed-by: Nilay Shroff Reviewed-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Signed-off-by: Guixin Liu Signed-off-by: Keith Busch --- drivers/nvme/target/core.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c index 43871a8f56ca..8c8c8627871f 100644 --- a/drivers/nvme/target/core.c +++ b/drivers/nvme/target/core.c @@ -1648,6 +1648,8 @@ struct nvmet_ctrl *nvmet_alloc_ctrl(struct nvmet_alloc_ctrl_args *args) INIT_DELAYED_WORK(&ctrl->ka_work, nvmet_keep_alive_timer); memcpy(ctrl->hostnqn, args->hostnqn, NVMF_NQN_SIZE); + if (args->hostid) + uuid_copy(&ctrl->hostid, args->hostid); kref_init(&ctrl->ref); ctrl->subsys = subsys; @@ -1706,9 +1708,6 @@ struct nvmet_ctrl *nvmet_alloc_ctrl(struct nvmet_alloc_ctrl_args *args) nvmet_start_keep_alive_timer(ctrl); - if (args->hostid) - uuid_copy(&ctrl->hostid, args->hostid); - dhchap_status = nvmet_setup_auth(ctrl, args->sq, false); if (dhchap_status) { pr_err("Failed to setup authentication, dhchap status %u\n",