From 927011b65a875302d08709bbe82eaf4d0d96c5d5 Mon Sep 17 00:00:00 2001 From: Yury Norov Date: Mon, 27 Apr 2026 22:49:41 -0400 Subject: drm/amdgpu: fix build for CONFIG_DRM_FBDEV_EMULATION=n MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The merge-commit 02e778f12359 ("Merge tag 'amd-drm-next-7.1-2026-03-12' of https://gitlab.freedesktop.org/agd5f/linux into drm-next") removes the stub for drm_fb_helper_gem_is_fb(), so the buld gets broken if DRM_FBDEV_EMULATION is not set. ‘drm_fb_helper_gem_is_fb’; did you mean ‘drm_fb_helper_from_client’? [-Wimplicit-function-declaration] 1777 | if (!drm_fb_helper_gem_is_fb(dev->fb_helper, fb->obj[0])) { | ^~~~~~~~~~~~~~~~~~~~~~~ | drm_fb_helper_from_client Restore it. Fixes: 02e778f12359 ("Merge tag 'amd-drm-next-7.1-2026-03-12' of https://gitlab.freedesktop.org/agd5f/linux into drm-next") Reviewed-by: Thomas Zimmermann Signed-off-by: Yury Norov Signed-off-by: Alex Deucher (cherry picked from commit 7b81bc38e92c2522484c42671401eaa023ae8831) --- include/drm/drm_fb_helper.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include/drm') diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h index bf391903443d..0c5e5ed7b5e7 100644 --- a/include/drm/drm_fb_helper.h +++ b/include/drm/drm_fb_helper.h @@ -273,6 +273,12 @@ int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper); int drm_fb_helper_initial_config(struct drm_fb_helper *fb_helper); bool drm_fb_helper_gem_is_fb(const struct drm_fb_helper *fb_helper, const struct drm_gem_object *obj); +#else +static inline bool drm_fb_helper_gem_is_fb(const struct drm_fb_helper *fb_helper, + const struct drm_gem_object *obj) +{ + return false; +} #endif #endif -- cgit v1.2.3 From b2ed01e7ad3de80333e9b962a44024b094bc0b2b Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Thomas=20Hellstr=C3=B6m?= Date: Tue, 28 Apr 2026 11:44:42 +0200 Subject: drm/ttm: Fix ttm_bo_swapout() infinite LRU walk on swapout failure MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When ttm_tt_swapout() fails, the current code calls ttm_resource_add_bulk_move() followed by ttm_resource_move_to_lru_tail() to restore the resource's bulk_move membership. However, ttm_resource_move_to_lru_tail() places the resource at the tail of the LRU list which, relative to the walk cursor's hitch node (placed immediately after the resource when it was yielded), puts the resource *in front of the* the hitch. The next list_for_each_entry_continue() from the hitch finds the same resource again, causing an infinite loop. Fix by deferring del_bulk_move to the success path only. On the success path, TTM_TT_FLAG_SWAPPED has just been set by ttm_tt_swapout() but the resource is still tracked in the bulk_move range, so ttm_resource_del_bulk_move()'s !ttm_resource_unevictable() guard would incorrectly skip the removal. Introduce ttm_resource_del_bulk_move_unevictable() which bypasses that guard. Reported-by: Jatin Kataria Fixes: fc5d96670eb2 ("drm/ttm: Move swapped objects off the manager's LRU list") Cc: Christian König Cc: Matthew Brost Cc: Cc: # v6.13+ Assisted-by: GitHub_Copilot:claude-sonnet-4.6 Signed-off-by: Thomas Hellström Reviewed-by: Christian König Tested-by: Boqun Feng Link: https://patch.msgid.link/20260428094442.16985-1-thomas.hellstrom@linux.intel.com --- include/drm/ttm/ttm_resource.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/drm') diff --git a/include/drm/ttm/ttm_resource.h b/include/drm/ttm/ttm_resource.h index 33e80f30b8b8..a5d386583fb6 100644 --- a/include/drm/ttm/ttm_resource.h +++ b/include/drm/ttm/ttm_resource.h @@ -448,6 +448,8 @@ void ttm_resource_add_bulk_move(struct ttm_resource *res, struct ttm_buffer_object *bo); void ttm_resource_del_bulk_move(struct ttm_resource *res, struct ttm_buffer_object *bo); +void ttm_resource_del_bulk_move_unevictable(struct ttm_resource *res, + struct ttm_buffer_object *bo); void ttm_resource_move_to_lru_tail(struct ttm_resource *res); void ttm_resource_init(struct ttm_buffer_object *bo, -- cgit v1.2.3 From 379e8f1ca5e919b130b40d8115d92a536e5f8d7a Mon Sep 17 00:00:00 2001 From: Boris Brezillon Date: Mon, 18 May 2026 13:41:45 +0200 Subject: drm/gem: Make the GEM LRU lock part of drm_device Recently, a few races have been discovered in the GEM LRU logic, all of them caused by the fact the LRU lock is accessed through gem->lru->lock, and that very same lock also protects changes to gem->lru, leading to situations where gem->lru needs to first be accessed without the lock held, to then get the lru to access the lock through and finally take the lock and do the expected operation. Currently, the only driver making use of this API (MSM) declares a device-wide lock, and the user we're about to add (panthor) will do the same. There's no evidence that we will ever have a driver that wants different pools of LRUs protected by different locks under the same drm_device. So we're better off moving this lock to drm_device and always locking it through obj->dev->gem_lru_mutex, or directly through dev->gem_lru_mutex. If anyone ever needs more fine-grained locking, this can be revisited to pass some drm_gem_lru_pool object representing the pool of LRUs under a specific lock, but for now, the per-device lock seems to be enough. Fixes: e7c2af13f811 ("drm/gem: Add LRU/shrinker helper") Reported-by: Chia-I Wu Closes: https://gitlab.freedesktop.org/panfrost/linux/-/work_items/86 Reviewed-by: Rob Clark Reviewed-by: Liviu Dudau Reviewed-by: Steven Price Reviewed-by: Chia-I Wu Link: https://patch.msgid.link/20260518-panthor-shrinker-fixes-v4-1-1920234470d5@collabora.com Signed-off-by: Boris Brezillon --- include/drm/drm_device.h | 7 +++++++ include/drm/drm_gem.h | 20 +++++++++----------- 2 files changed, 16 insertions(+), 11 deletions(-) (limited to 'include/drm') diff --git a/include/drm/drm_device.h b/include/drm/drm_device.h index bc78fb77cc27..768a8dae83c5 100644 --- a/include/drm/drm_device.h +++ b/include/drm/drm_device.h @@ -375,6 +375,13 @@ struct drm_device { * Root directory for debugfs files. */ struct dentry *debugfs_root; + + /** + * @gem_lru_mutex: + * + * Lock protecting movement of GEM objects between LRUs. + */ + struct mutex gem_lru_mutex; }; void drm_dev_set_dma_dev(struct drm_device *dev, struct device *dma_dev); diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h index 86f5846154f7..8a704f6a65c1 100644 --- a/include/drm/drm_gem.h +++ b/include/drm/drm_gem.h @@ -245,17 +245,11 @@ struct drm_gem_object_funcs { * for lockless &shrinker.count_objects, and provides * &drm_gem_lru_scan for driver's &shrinker.scan_objects * implementation. + * + * Any access to this kind of object must be done with + * drm_device::gem_lru_mutex held. */ struct drm_gem_lru { - /** - * @lock: - * - * Lock protecting movement of GEM objects between LRUs. All - * LRUs that the object can move between should be protected - * by the same lock. - */ - struct mutex *lock; - /** * @count: * @@ -453,6 +447,9 @@ struct drm_gem_object { * @lru: * * The current LRU list that the GEM object is on. + * + * Access to this field must be done with drm_device::gem_lru_mutex + * held. */ struct drm_gem_lru *lru; }; @@ -610,12 +607,13 @@ void drm_gem_unlock_reservations(struct drm_gem_object **objs, int count, int drm_gem_dumb_map_offset(struct drm_file *file, struct drm_device *dev, u32 handle, u64 *offset); -void drm_gem_lru_init(struct drm_gem_lru *lru, struct mutex *lock); +void drm_gem_lru_init(struct drm_gem_lru *lru); void drm_gem_lru_remove(struct drm_gem_object *obj); void drm_gem_lru_move_tail_locked(struct drm_gem_lru *lru, struct drm_gem_object *obj); void drm_gem_lru_move_tail(struct drm_gem_lru *lru, struct drm_gem_object *obj); unsigned long -drm_gem_lru_scan(struct drm_gem_lru *lru, +drm_gem_lru_scan(struct drm_device *dev, + struct drm_gem_lru *lru, unsigned int nr_to_scan, unsigned long *remaining, bool (*shrink)(struct drm_gem_object *obj, struct ww_acquire_ctx *ticket), -- cgit v1.2.3