4.15-stable review patch. If anyone has any objections, please let me know.
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From: Lukas Wunner lukas@wunner.de
commit 76f2e2bc627f7d08360ac731b6277d744d4eb599 upstream.
Unbinding nouveau on a dual GPU MacBook Pro oopses because we iterate over the bl_connectors list in nouveau_backlight_exit() but skipped initializing it in nouveau_backlight_init(). Stacktrace for posterity:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000010 IP: nouveau_backlight_exit+0x2b/0x70 [nouveau] nouveau_display_destroy+0x29/0x80 [nouveau] nouveau_drm_unload+0x65/0xe0 [nouveau] drm_dev_unregister+0x3c/0xe0 [drm] drm_put_dev+0x2e/0x60 [drm] nouveau_drm_device_remove+0x47/0x70 [nouveau] pci_device_remove+0x36/0xb0 device_release_driver_internal+0x157/0x220 driver_detach+0x39/0x70 bus_remove_driver+0x51/0xd0 pci_unregister_driver+0x2a/0xa0 nouveau_drm_exit+0x15/0xfb0 [nouveau] SyS_delete_module+0x18c/0x290 system_call_fast_compare_end+0xc/0x6f
Fixes: b53ac1ee12a3 ("drm/nouveau/bl: Do not register interface if Apple GMUX detected") Cc: stable@vger.kernel.org # v4.10+ Cc: Pierre Moreau pierre.morrow@free.fr Signed-off-by: Lukas Wunner lukas@wunner.de Signed-off-by: Ben Skeggs bskeggs@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/gpu/drm/nouveau/nouveau_backlight.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/gpu/drm/nouveau/nouveau_backlight.c +++ b/drivers/gpu/drm/nouveau/nouveau_backlight.c @@ -268,13 +268,13 @@ nouveau_backlight_init(struct drm_device struct nvif_device *device = &drm->client.device; struct drm_connector *connector;
+ INIT_LIST_HEAD(&drm->bl_connectors); + if (apple_gmux_present()) { NV_INFO(drm, "Apple GMUX detected: not registering Nouveau backlight interface\n"); return 0; }
- INIT_LIST_HEAD(&drm->bl_connectors); - list_for_each_entry(connector, &dev->mode_config.connector_list, head) { if (connector->connector_type != DRM_MODE_CONNECTOR_LVDS && connector->connector_type != DRM_MODE_CONNECTOR_eDP)