[CI 06/10] drm/i915: Show i915_gem_context owner in debugfs

Chris Wilson
2016-05-24T13:53:59Z

Print the context's owner (via the pid under file_priv) under debugfs.
In doing so, we must be careful that the filp is not accessed after it
is freed (notified via i915_gem_context_close).

v2: Mark the file_priv as closed.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
drivers/gpu/drm/i915/i915_debugfs.c | 17 +++++++++++++++--
drivers/gpu/drm/i915/i915_gem_context.c | 3 ++-
2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 424e11efa3e1..e81b795005b9 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -2014,9 +2014,22 @@ static int i915_context_status(struct seq_file *m, void *unused)
continue;

seq_printf(m, "HW context %u ", ctx->hw_id);
+ if (IS_ERR(ctx->file_priv)) {
+ seq_puts(m, "(deleted) ");
+ } else if (ctx->file_priv) {
+ struct pid *pid = ctx->file_priv->file->pid;
+ struct task_struct *task;
+
+ task = get_pid_task(pid, PIDTYPE_PID);
+ if (task) {
+ seq_printf(m, "(%s [%d]) ",
+ task->comm, task->pid);
+ put_task_struct(task);
+ }
+ } else
+ seq_puts(m, "(kernel) ");
+
describe_ctx(m, ctx);
- if (ctx == dev_priv->kernel_context)
- seq_printf(m, "(kernel context) ");

if (i915.enable_execlists) {
seq_putc(m, '\n');
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 104d4819aca8..8d8c79b88816 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -468,6 +468,7 @@ static int context_idr_cleanup(int id, void *p, void *data)
{
struct i915_gem_context *ctx = p;

+ ctx->file_priv = ERR_PTR(-EBADF);
i915_gem_context_unreference(ctx);
return 0;
}
@@ -938,7 +939,7 @@ int i915_gem_context_destroy_ioctl(struct drm_device *dev, void *data,
return PTR_ERR(ctx);
}

- idr_remove(&ctx->file_priv->context_idr, ctx->user_handle);
+ idr_remove(&file_priv->context_idr, ctx->user_handle);
i915_gem_context_unreference(ctx);
mutex_unlock(&dev->struct_mutex);