From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- include/drm/drm_writeback.h | 186 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 186 insertions(+) create mode 100644 include/drm/drm_writeback.h (limited to 'include/drm/drm_writeback.h') diff --git a/include/drm/drm_writeback.h b/include/drm/drm_writeback.h new file mode 100644 index 000000000..c380a7b8f --- /dev/null +++ b/include/drm/drm_writeback.h @@ -0,0 +1,186 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * (C) COPYRIGHT 2016 ARM Limited. All rights reserved. + * Author: Brian Starkey + * + * This program is free software and is provided to you under the terms of the + * GNU General Public License version 2 as published by the Free Software + * Foundation, and any use by you of this program is subject to the terms + * of such GNU licence. + */ + +#ifndef __DRM_WRITEBACK_H__ +#define __DRM_WRITEBACK_H__ +#include +#include +#include + +/** + * struct drm_writeback_connector - DRM writeback connector + */ +struct drm_writeback_connector { + /** + * @base: base drm_connector object + */ + struct drm_connector base; + + /** + * @encoder: Internal encoder used by the connector to fulfill + * the DRM framework requirements. The users of the + * @drm_writeback_connector control the behaviour of the @encoder + * by passing the @enc_funcs parameter to drm_writeback_connector_init() + * function. + * For users of drm_writeback_connector_init_with_encoder(), this field + * is not valid as the encoder is managed within their drivers. + */ + struct drm_encoder encoder; + + /** + * @pixel_formats_blob_ptr: + * + * DRM blob property data for the pixel formats list on writeback + * connectors + * See also drm_writeback_connector_init() + */ + struct drm_property_blob *pixel_formats_blob_ptr; + + /** @job_lock: Protects job_queue */ + spinlock_t job_lock; + + /** + * @job_queue: + * + * Holds a list of a connector's writeback jobs; the last item is the + * most recent. The first item may be either waiting for the hardware + * to begin writing, or currently being written. + * + * See also: drm_writeback_queue_job() and + * drm_writeback_signal_completion() + */ + struct list_head job_queue; + + /** + * @fence_context: + * + * timeline context used for fence operations. + */ + unsigned int fence_context; + /** + * @fence_lock: + * + * spinlock to protect the fences in the fence_context. + */ + spinlock_t fence_lock; + /** + * @fence_seqno: + * + * Seqno variable used as monotonic counter for the fences + * created on the connector's timeline. + */ + unsigned long fence_seqno; + /** + * @timeline_name: + * + * The name of the connector's fence timeline. + */ + char timeline_name[32]; +}; + +/** + * struct drm_writeback_job - DRM writeback job + */ +struct drm_writeback_job { + /** + * @connector: + * + * Back-pointer to the writeback connector associated with the job + */ + struct drm_writeback_connector *connector; + + /** + * @prepared: + * + * Set when the job has been prepared with drm_writeback_prepare_job() + */ + bool prepared; + + /** + * @cleanup_work: + * + * Used to allow drm_writeback_signal_completion to defer dropping the + * framebuffer reference to a workqueue + */ + struct work_struct cleanup_work; + + /** + * @list_entry: + * + * List item for the writeback connector's @job_queue + */ + struct list_head list_entry; + + /** + * @fb: + * + * Framebuffer to be written to by the writeback connector. Do not set + * directly, use drm_writeback_set_fb() + */ + struct drm_framebuffer *fb; + + /** + * @out_fence: + * + * Fence which will signal once the writeback has completed + */ + struct dma_fence *out_fence; + + /** + * @priv: + * + * Driver-private data + */ + void *priv; +}; + +static inline struct drm_writeback_connector * +drm_connector_to_writeback(struct drm_connector *connector) +{ + return container_of(connector, struct drm_writeback_connector, base); +} + +int drm_writeback_connector_init(struct drm_device *dev, + struct drm_writeback_connector *wb_connector, + const struct drm_connector_funcs *con_funcs, + const struct drm_encoder_helper_funcs *enc_helper_funcs, + const u32 *formats, int n_formats, + u32 possible_crtcs); + +int drm_writeback_connector_init_with_encoder(struct drm_device *dev, + struct drm_writeback_connector *wb_connector, + struct drm_encoder *enc, + const struct drm_connector_funcs *con_funcs, const u32 *formats, + int n_formats); + +int drmm_writeback_connector_init(struct drm_device *dev, + struct drm_writeback_connector *wb_connector, + const struct drm_connector_funcs *con_funcs, + struct drm_encoder *enc, + const u32 *formats, int n_formats); + +int drm_writeback_set_fb(struct drm_connector_state *conn_state, + struct drm_framebuffer *fb); + +int drm_writeback_prepare_job(struct drm_writeback_job *job); + +void drm_writeback_queue_job(struct drm_writeback_connector *wb_connector, + struct drm_connector_state *conn_state); + +void drm_writeback_cleanup_job(struct drm_writeback_job *job); + +void +drm_writeback_signal_completion(struct drm_writeback_connector *wb_connector, + int status); + +struct dma_fence * +drm_writeback_get_out_fence(struct drm_writeback_connector *wb_connector); +#endif -- cgit v1.3.1