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From:   Mark Menzynski <mmenzyns@redhat.com>
To:     linux-kernel@vger.kernel.org
Cc:     Mark Menzynski <mmenzyns@redhat.com>,
        Ben Skeggs <bskeggs@redhat.com>,
        Karol Herbst <kherbst@redhat.com>,
        Lyude Paul <lyude@redhat.com>, David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Sumit Semwal <sumit.semwal@linaro.org>,
        =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@amd.com>,
        dri-devel@lists.freedesktop.org, nouveau@lists.freedesktop.org,
        linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org
Subject: [PATCH] drm/nouveau: reorder nouveau_drm_device_fini
Date:   Wed,  4 May 2022 19:18:51 +0200
Message-Id: <20220504171851.17188-1-mmenzyns@redhat.com>
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Resources needed for output poll workers are destroyed in
nouveau_fbcon_fini() before output poll workers are cleared in
nouveau_display_fini(). This means there is a time between fbcon_fini
and display_fini, where if output poll happens, it crashes.

BUG: KASAN: use-after-free in
__drm_fb_helper_initial_config_and_unlock.cold+0x1f3/0x291
[drm_kms_helper]

Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Karol Herbst <kherbst@redhat.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: dri-devel@lists.freedesktop.org
Cc: nouveau@lists.freedesktop.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-media@vger.kernel.org
Cc: linaro-mm-sig@lists.linaro.org
Signed-off-by: Mark Menzynski <mmenzyns@redhat.com>
---
 drivers/gpu/drm/nouveau/nouveau_drm.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c
index 561309d447e0..773efdd20d2f 100644
--- a/drivers/gpu/drm/nouveau/nouveau_drm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_drm.c
@@ -588,12 +588,6 @@ nouveau_drm_device_init(struct drm_device *dev)
 	if (ret)
 		goto fail_dispctor;
 
-	if (dev->mode_config.num_crtc) {
-		ret = nouveau_display_init(dev, false, false);
-		if (ret)
-			goto fail_dispinit;
-	}
-
 	nouveau_debugfs_init(drm);
 	nouveau_hwmon_init(dev);
 	nouveau_svm_init(drm);
@@ -601,6 +595,12 @@ nouveau_drm_device_init(struct drm_device *dev)
 	nouveau_fbcon_init(dev);
 	nouveau_led_init(dev);
 
+	if (dev->mode_config.num_crtc) {
+		ret = nouveau_display_init(dev, false, false);
+		if (ret)
+			goto fail_dispinit;
+	}
+
 	if (nouveau_pmops_runtime()) {
 		pm_runtime_use_autosuspend(dev->dev);
 		pm_runtime_set_autosuspend_delay(dev->dev, 5000);
@@ -641,15 +641,14 @@ nouveau_drm_device_fini(struct drm_device *dev)
 		pm_runtime_forbid(dev->dev);
 	}
 
+	if (dev->mode_config.num_crtc)
+		nouveau_display_fini(dev, false, false);
 	nouveau_led_fini(dev);
 	nouveau_fbcon_fini(dev);
 	nouveau_dmem_fini(drm);
 	nouveau_svm_fini(drm);
 	nouveau_hwmon_fini(dev);
 	nouveau_debugfs_fini(drm);
-
-	if (dev->mode_config.num_crtc)
-		nouveau_display_fini(dev, false, false);
 	nouveau_display_destroy(dev);
 
 	nouveau_accel_fini(drm);
-- 
2.32.0