From: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com> To: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>, Jani Nikula <jani.nikula@linux.intel.com>, Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>, Chris Wilson <chris@chris-wilson.co.uk>, michal.wajdeczko@intel.com, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Janusz Krzysztofik <janusz.krzysztofik@intel.com> Subject: [PATCH] drm/i915: Use drm_dev_unplug() Date: Fri, 5 Apr 2019 09:26:57 +0200 [thread overview] Message-ID: <20190405072657.9997-1-janusz.krzysztofik@linux.intel.com> (raw) From: Janusz Krzysztofik <janusz.krzysztofik@intel.com> The driver does not currently support unbinding from a device which is in use. Since open file descriptors may still be pointing into kernel memory where the device structures used to be, entirely correct kernel panics protect the driver from being unbound as we should not be unbinding it before those dangling pointers have been made safe. According to the documentation found inside drivers/gpu/drm/drm_drv.c, drm_dev_unplug() should be used instead of drm_dev_unregister() in order to make a device inaccessible to users as soon as it is unpluged. Follow that advice to make those possibly dangling pointers safe, protected by DRM layer from a user who is otherwise left pointing into possibly reused kernel memory after the driver has been unbound from the device. Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik@intel.com> --- drivers/gpu/drm/i915/i915_drv.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c index 9df65d386d11..66163378c481 100644 --- a/drivers/gpu/drm/i915/i915_drv.c +++ b/drivers/gpu/drm/i915/i915_drv.c @@ -1596,7 +1596,7 @@ static void i915_driver_unregister(struct drm_i915_private *dev_priv) i915_pmu_unregister(dev_priv); i915_teardown_sysfs(dev_priv); - drm_dev_unregister(&dev_priv->drm); + drm_dev_unplug(&dev_priv->drm); i915_gem_shrinker_unregister(dev_priv); } -- 2.20.1
WARNING: multiple messages have this Message-ID (diff)
From: Janusz Krzysztofik <janusz.krzysztofik@linux.intel.com> To: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>, Jani Nikula <jani.nikula@linux.intel.com>, Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: Janusz Krzysztofik <janusz.krzysztofik@intel.com>, David Airlie <airlied@linux.ie>, intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org Subject: [PATCH] drm/i915: Use drm_dev_unplug() Date: Fri, 5 Apr 2019 09:26:57 +0200 [thread overview] Message-ID: <20190405072657.9997-1-janusz.krzysztofik@linux.intel.com> (raw) From: Janusz Krzysztofik <janusz.krzysztofik@intel.com> The driver does not currently support unbinding from a device which is in use. Since open file descriptors may still be pointing into kernel memory where the device structures used to be, entirely correct kernel panics protect the driver from being unbound as we should not be unbinding it before those dangling pointers have been made safe. According to the documentation found inside drivers/gpu/drm/drm_drv.c, drm_dev_unplug() should be used instead of drm_dev_unregister() in order to make a device inaccessible to users as soon as it is unpluged. Follow that advice to make those possibly dangling pointers safe, protected by DRM layer from a user who is otherwise left pointing into possibly reused kernel memory after the driver has been unbound from the device. Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik@intel.com> --- drivers/gpu/drm/i915/i915_drv.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c index 9df65d386d11..66163378c481 100644 --- a/drivers/gpu/drm/i915/i915_drv.c +++ b/drivers/gpu/drm/i915/i915_drv.c @@ -1596,7 +1596,7 @@ static void i915_driver_unregister(struct drm_i915_private *dev_priv) i915_pmu_unregister(dev_priv); i915_teardown_sysfs(dev_priv); - drm_dev_unregister(&dev_priv->drm); + drm_dev_unplug(&dev_priv->drm); i915_gem_shrinker_unregister(dev_priv); } -- 2.20.1 _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
next reply other threads:[~2019-04-05 7:27 UTC|newest] Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-04-05 7:26 Janusz Krzysztofik [this message] 2019-04-05 7:26 ` [PATCH] drm/i915: Use drm_dev_unplug() Janusz Krzysztofik 2019-04-05 7:41 ` Chris Wilson 2019-04-05 8:11 ` Janusz Krzysztofik 2019-04-05 8:24 ` Chris Wilson 2019-04-05 8:24 ` Chris Wilson 2019-04-05 11:38 ` Janusz Krzysztofik 2019-04-15 9:29 ` Daniel Vetter 2019-04-15 9:29 ` Daniel Vetter 2019-04-05 8:23 ` ✗ Fi.CI.BAT: failure for " Patchwork 2019-04-05 13:02 [PATCH 0/2] Stop users from using the device on driver unbind Janusz Krzysztofik 2019-04-05 13:02 ` [PATCH 1/2] drm/i915: Use drm_dev_unplug() Janusz Krzysztofik 2019-04-05 13:02 ` Janusz Krzysztofik 2019-04-15 9:32 ` Daniel Vetter 2019-04-18 14:51 ` [PATCH v2 0/1] Stop users from using the device on driver unbind Janusz Krzysztofik 2019-04-18 14:51 ` [PATCH v2 1/1] drm/i915: Use drm_dev_unplug() Janusz Krzysztofik 2019-04-05 13:02 ` [PATCH 2/2] drm/i915: Mark GEM wedged right after marking device unplugged Janusz Krzysztofik 2019-04-05 13:02 ` Janusz Krzysztofik 2019-04-05 16:20 ` ✗ Fi.CI.BAT: failure for Stop users from using the device on driver unbind Patchwork 2019-04-05 16:26 ` Chris Wilson 2019-04-05 17:37 ` Chris Wilson 2019-04-08 8:19 ` Janusz Krzysztofik
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