From bd670e5dfd2b01fd9692f61fa1456434c54026a4 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Linfeng=20Sun=C2=A0?= Date: Sat, 20 Jun 2026 18:09:59 +0800 Subject: [PATCH] vdpa_sim: fix cleanup after worker creation failure MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit vdpasim_create() leaves vdpasim->worker as an ERR_PTR when kthread_run_worker() fails. The error path then drops the device reference, which releases the partially initialized simulator. vdpasim_free() unconditionally passes the worker pointer to kthread_destroy_worker(), so the ERR_PTR is dereferenced and can trigger a general protection fault. Store the worker error, clear the pointer, and only clean up the worker when it was successfully initialized. Also make the release path tolerate partially initialized objects by guarding virtqueue and IOTLB cleanup, since the same release path can be reached from other initialization failures. I found this bug myself, though the patch was written with AI assistance. Fixes: 76acfa7bc54f ("vdpa_sim: use kthread worker") Assisted-by: OpenAI-Codex:GPT-5 Reviewed-by: Eugenio Pérez Signed-off-by: Linfeng Sun  Message-ID: <20260620100959.2070316-1-slf@hdu.edu.cn> Signed-off-by: Michael S. Tsirkin --- drivers/vdpa/vdpa_sim/vdpa_sim.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-) diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c index 4d116644851d..c748fe451163 100644 --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c @@ -233,8 +233,11 @@ struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr, kthread_init_work(&vdpasim->work, vdpasim_work_fn); vdpasim->worker = kthread_run_worker(0, "vDPA sim worker: %s", dev_attr->name); - if (IS_ERR(vdpasim->worker)) + if (IS_ERR(vdpasim->worker)) { + ret = PTR_ERR(vdpasim->worker); + vdpasim->worker = NULL; goto err_iommu; + } mutex_init(&vdpasim->mutex); spin_lock_init(&vdpasim->iommu_lock); @@ -746,18 +749,24 @@ static void vdpasim_free(struct vdpa_device *vdpa) struct vdpasim *vdpasim = vdpa_to_sim(vdpa); int i; - kthread_cancel_work_sync(&vdpasim->work); - kthread_destroy_worker(vdpasim->worker); + if (vdpasim->worker) { + kthread_cancel_work_sync(&vdpasim->work); + kthread_destroy_worker(vdpasim->worker); + } - for (i = 0; i < vdpasim->dev_attr.nvqs; i++) { - vringh_kiov_cleanup(&vdpasim->vqs[i].out_iov); - vringh_kiov_cleanup(&vdpasim->vqs[i].in_iov); + if (vdpasim->vqs) { + for (i = 0; i < vdpasim->dev_attr.nvqs; i++) { + vringh_kiov_cleanup(&vdpasim->vqs[i].out_iov); + vringh_kiov_cleanup(&vdpasim->vqs[i].in_iov); + } } vdpasim->dev_attr.free(vdpasim); - for (i = 0; i < vdpasim->dev_attr.nas; i++) - vhost_iotlb_reset(&vdpasim->iommu[i]); + if (vdpasim->iommu) { + for (i = 0; i < vdpasim->dev_attr.nas; i++) + vhost_iotlb_reset(&vdpasim->iommu[i]); + } kfree(vdpasim->iommu); kfree(vdpasim->iommu_pt); kfree(vdpasim->vqs);