From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock Add a sleepable verifier test that loads a graph-node local kptr in an explicit RCU read-side critical section, then passes its node to bpf_rbtree_remove() after the section ends. Before the verifier fix, the stale NON_OWN_REF flag makes the node look like a live borrowed reference and the program is accepted. After the fix, the pointer is demoted without NON_OWN_REF and the graph kfunc argument is rejected. Also exercise a graph kptr loaded while a spin lock provides implicit RCU protection. The pointer must be invalidated when the lock is released, which guards the required ordering between non-owning-reference invalidation and RCU demotion. Update the existing fault-protected load test state description. The post-unlock pointer no longer carries NON_OWN_REF, but remains readable because the load is rewritten to use BPF_PROBE_MEM. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- include/drm/drm_auth.h | 139 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 139 insertions(+) create mode 100644 include/drm/drm_auth.h (limited to 'include/drm/drm_auth.h') diff --git a/include/drm/drm_auth.h b/include/drm/drm_auth.h new file mode 100644 index 000000000..50131383e --- /dev/null +++ b/include/drm/drm_auth.h @@ -0,0 +1,139 @@ +#ifndef _DRM_AUTH_H_ +#define _DRM_AUTH_H_ + +/* + * Internal Header for the Direct Rendering Manager + * + * Copyright 2016 Intel Corporation + * + * Author: Daniel Vetter + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice (including the next + * paragraph) shall be included in all copies or substantial portions of the + * Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR + * OTHER DEALINGS IN THE SOFTWARE. + */ + +#include +#include +#include + +struct drm_file; + +/** + * struct drm_master - drm master structure + * + * @refcount: Refcount for this master object. + * @dev: Link back to the DRM device + * @driver_priv: Pointer to driver-private information. + * + * Note that master structures are only relevant for the legacy/primary device + * nodes, hence there can only be one per device, not one per drm_minor. + */ +struct drm_master { + struct kref refcount; + struct drm_device *dev; + /** + * @unique: Unique identifier: e.g. busid. Protected by + * &drm_device.master_mutex. + */ + char *unique; + /** + * @unique_len: Length of unique field. Protected by + * &drm_device.master_mutex. + */ + int unique_len; + /** + * @magic_map: Map of used authentication tokens. Protected by + * &drm_device.master_mutex. + */ + struct idr magic_map; + void *driver_priv; + + /** + * @lessor: + * + * Lease grantor, only set if this &struct drm_master represents a + * lessee holding a lease of objects from @lessor. Full owners of the + * device have this set to NULL. + * + * The lessor does not change once it's set in drm_lease_create(), and + * each lessee holds a reference to its lessor that it releases upon + * being destroyed in drm_lease_destroy(). + * + * See also the :ref:`section on display resource leasing + * `. + */ + struct drm_master *lessor; + + /** + * @lessee_id: + * + * ID for lessees. Owners (i.e. @lessor is NULL) always have ID 0. + * Protected by &drm_device.mode_config's &drm_mode_config.idr_mutex. + */ + int lessee_id; + + /** + * @lessee_list: + * + * List entry of lessees of @lessor, where they are linked to @lessees. + * Not used for owners. Protected by &drm_device.mode_config's + * &drm_mode_config.idr_mutex. + */ + struct list_head lessee_list; + + /** + * @lessees: + * + * List of drm_masters leasing from this one. Protected by + * &drm_device.mode_config's &drm_mode_config.idr_mutex. + * + * This list is empty if no leases have been granted, or if all lessees + * have been destroyed. Since lessors are referenced by all their + * lessees, this master cannot be destroyed unless the list is empty. + */ + struct list_head lessees; + + /** + * @leases: + * + * Objects leased to this drm_master. Protected by + * &drm_device.mode_config's &drm_mode_config.idr_mutex. + * + * Objects are leased all together in drm_lease_create(), and are + * removed all together when the lease is revoked. + */ + struct idr leases; + + /** + * @lessee_idr: + * + * All lessees under this owner (only used where @lessor is NULL). + * Protected by &drm_device.mode_config's &drm_mode_config.idr_mutex. + */ + struct idr lessee_idr; +}; + +struct drm_master *drm_master_get(struct drm_master *master); +struct drm_master *drm_file_get_master(struct drm_file *file_priv); +void drm_master_put(struct drm_master **master); +bool drm_is_current_master(struct drm_file *fpriv); + +struct drm_master *drm_master_create(struct drm_device *dev); + +#endif -- cgit v1.3.1