From 2c7367626733e27d6f6d9906db7a31ada587566b Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Sat, 17 Jun 2017 12:57:44 +0100 Subject: [PATCH] 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: 1d2ac403ae3b ("drm: Protect dev->filelist with its own mutex") Fixes: c84455b4bacc ("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: Chris Wilson Cc: Daniel Vetter Cc: Joonas Lahtinen Link: http://patchwork.freedesktop.org/patch/msgid/20170617115744.4452-1-chris@chris-wilson.co.uk Reviewed-by: Tvrtko Ursulin (cherry picked from commit 0caf81b5c53d9bd332a95dbcb44db8de0b397a7c) Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_debugfs.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c index d689e511744e..4bd1467c17b1 100644 --- a/drivers/gpu/drm/i915/i915_debugfs.c +++ b/drivers/gpu/drm/i915/i915_debugfs.c @@ -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 : "", stats); rcu_read_unlock(); + mutex_unlock(&dev->struct_mutex); } mutex_unlock(&dev->filelist_mutex); -- 2.20.1