From: Neil Armstrong narmstrong@baylibre.com
commit 7cfc4ea78fc103ea51ecbacd9236abb5b1c490d2 upstream.
When main component is not probed, by example when the dw-hdmi module is not loaded yet or in probe defer, the following crash appears on shutdown:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000038 ... pc : meson_drv_shutdown+0x24/0x50 lr : platform_drv_shutdown+0x20/0x30 ... Call trace: meson_drv_shutdown+0x24/0x50 platform_drv_shutdown+0x20/0x30 device_shutdown+0x158/0x360 kernel_restart_prepare+0x38/0x48 kernel_restart+0x18/0x68 __do_sys_reboot+0x224/0x250 __arm64_sys_reboot+0x24/0x30 ...
Simply check if the priv struct has been allocated before using it.
Fixes: fa0c16caf3d7 ("drm: meson_drv add shutdown function") Reported-by: Stefan Agner stefan@agner.ch Signed-off-by: Neil Armstrong narmstrong@baylibre.com Tested-by: Martin Blumenstingl martin.blumenstingl@googlemail.com Reviewed-by: Martin Blumenstingl martin.blumenstingl@googlemail.com Link: https://patchwork.freedesktop.org/patch/msgid/20210430082744.3638743-1-narms... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/meson/meson_drv.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)
--- a/drivers/gpu/drm/meson/meson_drv.c +++ b/drivers/gpu/drm/meson/meson_drv.c @@ -364,11 +364,12 @@ static int meson_probe_remote(struct pla static void meson_drv_shutdown(struct platform_device *pdev) { struct meson_drm *priv = dev_get_drvdata(&pdev->dev); - struct drm_device *drm = priv->drm;
- DRM_DEBUG_DRIVER("\n"); - drm_kms_helper_poll_fini(drm); - drm_atomic_helper_shutdown(drm); + if (!priv) + return; + + drm_kms_helper_poll_fini(priv->drm); + drm_atomic_helper_shutdown(priv->drm); }
static int meson_drv_probe(struct platform_device *pdev)