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

[Lucas De Marchi]

On Wed, Dec 11, 2019 at 12:10:41PM +0530, Bharadiya,Pankaj wrote:
>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 at 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?

I said it seems that it's the gmbus_teardown() that is out of place.
Have you seen my comment above? Why are we duplicating the bw_state on
the module-remove code path?

Lucas De Marchi

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