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Commit 2c736762 authored by Chris Wilson's avatar Chris Wilson Committed by Daniel Vetter
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drm/i915: Hold struct_mutex for per-file stats in debugfs/i915_gem_object 

As we walk the obj->vma_list in per_file_stats(), we need to hold
struct_mutex to prevent alteration of that list.

Fixes: 1d2ac403 ("drm: Protect dev->filelist with its own mutex")
Fixes: c84455b4 ("drm/i915: Move debug only per-request pid tracking from request to ctx")
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101460


Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170617115744.4452-1-chris@chris-wilson.co.uk


Reviewed-by: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
(cherry picked from commit 0caf81b5)
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent d8462d0a

drivers/gpu/drm/i915/i915_debugfs.c

+5 −1
Original line number Diff line number Diff line
@@ -292,6 +292,8 @@ static int per_file_stats(int id, void *ptr, void *data) 
	struct file_stats *stats = data;

	struct i915_vma *vma;



	lockdep_assert_held(&obj->base.dev->struct_mutex);



	stats->count++;

	stats->total += obj->base.size;

	if (!obj->bind_count)
@@ -476,6 +478,8 @@ static int i915_gem_object_info(struct seq_file *m, void *data) 
		struct drm_i915_gem_request *request;

		struct task_struct *task;



		mutex_lock(&dev->struct_mutex);



		memset(&stats, 0, sizeof(stats));

		stats.file_priv = file->driver_priv;

		spin_lock(&file->table_lock);
@@ -487,7 +491,6 @@ static int i915_gem_object_info(struct seq_file *m, void *data) 
		 * still alive (e.g. get_pid(current) => fork() => exit()).

		 * Therefore, we need to protect this ->comm access using RCU.

		 */

		mutex_lock(&dev->struct_mutex);

		request = list_first_entry_or_null(&file_priv->mm.request_list,

						   struct drm_i915_gem_request,

						   client_link);
@@ -497,6 +500,7 @@ static int i915_gem_object_info(struct seq_file *m, void *data) 
				PIDTYPE_PID);

		print_file_stats(m, task ? task->comm : "<unknown>", stats);

		rcu_read_unlock();



		mutex_unlock(&dev->struct_mutex);

	}

	mutex_unlock(&dev->filelist_mutex);