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From: Danilo Krummrich <dakr@redhat.com>
To: daniel@ffwll.ch, airlied@linux.ie, tzimmermann@suse.de,
	mripard@kernel.org, stefan@agner.ch, alison.wang@nxp.com
Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	Danilo Krummrich <dakr@redhat.com>
Subject: [PATCH drm-misc-next v2 5/9] drm/fsl-dcu: use drm_dev_unplug()
Date: Sat,  1 Oct 2022 16:57:58 +0200	[thread overview]
Message-ID: <20221001145802.515916-6-dakr@redhat.com> (raw)
In-Reply-To: <20221001145802.515916-1-dakr@redhat.com>

When the driver is unbound, there might still be users in userspace
having an open fd and are calling into the driver.

While this is fine for drm managed resources, it is not for resources
bound to the device/driver lifecycle, e.g. clocks or MMIO mappings.

To prevent use-after-free issues we need to protect those resources with
drm_dev_enter() and drm_dev_exit(). This does only work if we indicate
that the drm device was unplugged, hence use drm_dev_unplug() instead of
drm_dev_unregister().

Protecting the particular resources with drm_dev_enter()/drm_dev_exit()
is handled by subsequent patches.

Signed-off-by: Danilo Krummrich <dakr@redhat.com>
---
 drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
index 4139f674c5de..3ac57516c3fe 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
@@ -340,7 +340,7 @@ static int fsl_dcu_drm_remove(struct platform_device *pdev)
 	struct fsl_dcu_drm_device *fsl_dev = platform_get_drvdata(pdev);
 	struct drm_device *drm = &fsl_dev->base;
 
-	drm_dev_unregister(drm);
+	drm_dev_unplug(drm);
 	clk_disable_unprepare(fsl_dev->clk);
 	clk_unregister(fsl_dev->pix_clk);
 
-- 
2.37.3


WARNING: multiple messages have this Message-ID (diff)
From: Danilo Krummrich <dakr@redhat.com>
To: daniel@ffwll.ch, airlied@linux.ie, tzimmermann@suse.de,
	mripard@kernel.org, stefan@agner.ch, alison.wang@nxp.com
Cc: Danilo Krummrich <dakr@redhat.com>,
	linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org
Subject: [PATCH drm-misc-next v2 5/9] drm/fsl-dcu: use drm_dev_unplug()
Date: Sat,  1 Oct 2022 16:57:58 +0200	[thread overview]
Message-ID: <20221001145802.515916-6-dakr@redhat.com> (raw)
In-Reply-To: <20221001145802.515916-1-dakr@redhat.com>

When the driver is unbound, there might still be users in userspace
having an open fd and are calling into the driver.

While this is fine for drm managed resources, it is not for resources
bound to the device/driver lifecycle, e.g. clocks or MMIO mappings.

To prevent use-after-free issues we need to protect those resources with
drm_dev_enter() and drm_dev_exit(). This does only work if we indicate
that the drm device was unplugged, hence use drm_dev_unplug() instead of
drm_dev_unregister().

Protecting the particular resources with drm_dev_enter()/drm_dev_exit()
is handled by subsequent patches.

Signed-off-by: Danilo Krummrich <dakr@redhat.com>
---
 drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
index 4139f674c5de..3ac57516c3fe 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
@@ -340,7 +340,7 @@ static int fsl_dcu_drm_remove(struct platform_device *pdev)
 	struct fsl_dcu_drm_device *fsl_dev = platform_get_drvdata(pdev);
 	struct drm_device *drm = &fsl_dev->base;
 
-	drm_dev_unregister(drm);
+	drm_dev_unplug(drm);
 	clk_disable_unprepare(fsl_dev->clk);
 	clk_unregister(fsl_dev->pix_clk);
 
-- 
2.37.3


  parent reply	other threads:[~2022-10-01 14:58 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-01 14:57 [PATCH drm-misc-next v2 0/9] drm/fsl-dcu: use drm managed resources Danilo Krummrich
2022-10-01 14:57 ` Danilo Krummrich
2022-10-01 14:57 ` [PATCH drm-misc-next v2 1/9] drm/fsl-dcu: use drmm_* to allocate driver structures Danilo Krummrich
2022-10-01 14:57   ` Danilo Krummrich
2022-10-01 14:57 ` [PATCH drm-misc-next v2 2/9] drm/fsl-dcu: replace drm->dev_private with drm_to_fsl_dcu_drm_dev() Danilo Krummrich
2022-10-01 14:57   ` Danilo Krummrich
2022-10-01 14:57 ` [PATCH drm-misc-next v2 3/9] drm/fsl-dcu: crtc: use drmm_crtc_init_with_planes() Danilo Krummrich
2022-10-01 14:57   ` Danilo Krummrich
2022-10-01 14:57 ` [PATCH drm-misc-next v2 4/9] drm/fsl-dcu: plane: use drm managed resources Danilo Krummrich
2022-10-01 14:57   ` Danilo Krummrich
2022-10-01 14:57 ` Danilo Krummrich [this message]
2022-10-01 14:57   ` [PATCH drm-misc-next v2 5/9] drm/fsl-dcu: use drm_dev_unplug() Danilo Krummrich
2022-10-01 14:57 ` [PATCH drm-misc-next v2 6/9] drm/fsl-dcu: plane: protect device resources after removal Danilo Krummrich
2022-10-01 14:57   ` Danilo Krummrich
2022-10-01 14:58 ` [PATCH drm-misc-next v2 7/9] drm/fsl-dcu: crtc: " Danilo Krummrich
2022-10-01 14:58   ` Danilo Krummrich
2022-10-01 14:58 ` [PATCH drm-misc-next v2 8/9] drm/fsl-dcu: remove trailing return statements Danilo Krummrich
2022-10-01 14:58   ` Danilo Krummrich
2022-10-01 14:58 ` [PATCH drm-misc-next v2 9/9] drm/fsl-dcu: remove calls to drm_mode_config_cleanup() Danilo Krummrich
2022-10-01 14:58   ` Danilo Krummrich

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