Re: [Intel-gfx] [PATCH] drm/i915/display: cleanup intel_bw_state on i915 module removal

["Bharadiya,Pankaj" <pankaj.laxminarayan.bharadiya@intel.com>]

On Tue, Dec 10, 2019 at 09:57:39PM -0800, Lucas De Marchi wrote:
> On Mon, Dec 09, 2019 at 08:09:02PM +0530, Pankaj Bharadiya wrote:
> >intel_bw_state allocated memory is not getting freed even after
> >module removal.
> >
> >kmemleak reported backtrace:
> >
> >   [<0000000079019739>] kmemdup+0x17/0x40
> >   [<00000000d58c1b9d>] intel_bw_duplicate_state+0x1b/0x40 [i915]
> >   [<000000007423ed0c>] drm_atomic_get_private_obj_state+0xca/0x140
> >   [<00000000100e3533>] intel_bw_atomic_check+0x133/0x350 [i915]
> >   [<00000000126d0e0c>] intel_atomic_check+0x1ab7/0x20d0 [i915]
> >   [<00000000d5dfc004>] drm_atomic_check_only+0x563/0x810
> >   [<00000000c9379611>] drm_atomic_commit+0xe/0x50
> >   [<00000000ec82b765>] drm_atomic_helper_disable_all+0x133/0x160
> >   [<000000003c44760c>] drm_atomic_helper_shutdown+0x65/0xc0
> >   [<00000000414e3e5c>] i915_driver_remove+0xcb/0x130 [i915]
> >   [<00000000f8544c2a>] i915_pci_remove+0x19/0x40 [i915]
> >   [<000000002dcbd148>] pci_device_remove+0x36/0xb0
> >   [<000000003c8c6b0a>] device_release_driver_internal+0xe0/0x1c0
> >   [<00000000580e9566>] unbind_store+0xc3/0x120
> >   [<00000000869d0df5>] kernfs_fop_write+0x104/0x190
> >   [<000000004dc1a355>] vfs_write+0xb9/0x1d0
> 
> what I find strange in this is that the last state was allocated by the
> "driver remove" code path.
> 
> >
> >Call the drm_atomic_private_obj_fini(), which inturn calls the
> >intel_bw_destroy_state() to make sure the intel_bw_state memory is
> >freed properly.
> >
> >Signed-off-by: Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@intel.com>
> >---
> >drivers/gpu/drm/i915/display/intel_bw.c      | 5 +++++
> >drivers/gpu/drm/i915/display/intel_bw.h      | 1 +
> >drivers/gpu/drm/i915/display/intel_display.c | 2 ++
> >3 files changed, 8 insertions(+)
> >
> >diff --git a/drivers/gpu/drm/i915/display/intel_bw.c b/drivers/gpu/drm/i915/display/intel_bw.c
> >index dcb66a33be9b..b228671d5a5d 100644
> >--- a/drivers/gpu/drm/i915/display/intel_bw.c
> >+++ b/drivers/gpu/drm/i915/display/intel_bw.c
> >@@ -486,3 +486,8 @@ int intel_bw_init(struct drm_i915_private *dev_priv)
> >
> >	return 0;
> >}
> >+
> >+void intel_bw_cleanup(struct drm_i915_private *dev_priv)
> >+{
> >+	drm_atomic_private_obj_fini(&dev_priv->bw_obj);
> >+}
> >diff --git a/drivers/gpu/drm/i915/display/intel_bw.h b/drivers/gpu/drm/i915/display/intel_bw.h
> >index 9db10af012f4..20b9ad241802 100644
> >--- a/drivers/gpu/drm/i915/display/intel_bw.h
> >+++ b/drivers/gpu/drm/i915/display/intel_bw.h
> >@@ -25,6 +25,7 @@ struct intel_bw_state {
> >
> >void intel_bw_init_hw(struct drm_i915_private *dev_priv);
> >int intel_bw_init(struct drm_i915_private *dev_priv);
> >+void intel_bw_cleanup(struct drm_i915_private *dev_priv);
> >int intel_bw_atomic_check(struct intel_atomic_state *state);
> >void intel_bw_crtc_update(struct intel_bw_state *bw_state,
> >			  const struct intel_crtc_state *crtc_state);
> >diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> >index 3190aa27ffdc..756eb90b1bb1 100644
> >--- a/drivers/gpu/drm/i915/display/intel_display.c
> >+++ b/drivers/gpu/drm/i915/display/intel_display.c
> >@@ -17912,6 +17912,8 @@ void intel_modeset_driver_remove(struct drm_i915_private *i915)
> >
> >	intel_gmbus_teardown(i915);
> >
> >+	intel_bw_cleanup(i915);
> 
> This doesn't seem to match the (reverse) order of
> intel_modeset_init()... but it's actually the gmbus_teardown() that is
> out of place. Did you check if it's not a wrong shutdown ordering?
>

In intel_modeset_init(), intel_gmbus_setup() happens after
intel_bw_init().
I think the patch follows the reverse ordering properly.
Am I missing anything?

Thanks,
Pankaj

> thanks
> Lucas De Marchi
> 
> >+
> >	destroy_workqueue(i915->flip_wq);
> >	destroy_workqueue(i915->modeset_wq);
> >
> >-- 
> >2.23.0
> >
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