Hi
Am 11.05.26 um 19:22 schrieb Icenowy Zheng:
在 2026-05-12二的 02:01 +0900，Myeonghun Pak写道：
lsdc_pci_probe() initializes KMS polling before setting up vblank
support,
requesting the IRQ and registering the DRM device. If any of those
later
steps fails, probe returns without finalizing polling. The remove
path has
the same lifetime gap when tearing down a successfully registered
device.
Route those probe failures through a poll cleanup label. Also
finalize
polling from remove before unregistering the DRM device.
Interesting, but it looks like a `drmm_kms_helper_poll_init` function
exists (while rarely used).
Maybe it's better to switch to this? Or maybe there's some reason not
to use this?
Agreed. DRM drivers are advised to use managed cleanup for their data
structures. So rather switch to drmm_kms_helper_poll_init(). That also
resolves the problem that loongson never calls poll_fini on regular
removals.
Best regards
Thomas
Thanks,
Icenowy
This issue was identified during our ongoing static-analysis research
while
reviewing kernel code.
Fixes: f39db26c5428 ("drm: Add kms driver for loongson display
controller")
Cc: [email protected]
Co-developed-by: Ijae Kim <[email protected]>
Signed-off-by: Ijae Kim <[email protected]>
Signed-off-by: Myeonghun Pak <[email protected]>
---
drivers/gpu/drm/loongson/lsdc_drv.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/loongson/lsdc_drv.c
b/drivers/gpu/drm/loongson/lsdc_drv.c
index abf5bf68ee..3db1f8690a 100644
--- a/drivers/gpu/drm/loongson/lsdc_drv.c
+++ b/drivers/gpu/drm/loongson/lsdc_drv.c
@@ -297,7 +297,7 @@ static int lsdc_pci_probe(struct pci_dev *pdev,
const struct pci_device_id *ent)
if (loongson_vblank) {
ret = drm_vblank_init(ddev, descp->num_of_crtc);
if (ret)
- return ret;
+ goto err_poll_fini;
ret = devm_request_irq(&pdev->dev, pdev->irq,
descp->funcs->irq_handler,
@@ -305,7 +305,7 @@ static int lsdc_pci_probe(struct pci_dev *pdev,
const struct pci_device_id *ent)
dev_name(&pdev->dev), ddev);
if (ret) {
drm_err(ddev, "Failed to register interrupt:
%d\n", ret);
- return ret;
+ goto err_poll_fini;
}
drm_info(ddev, "registered irq: %u\n", pdev->irq);
@@ -313,17 +313,22 @@ static int lsdc_pci_probe(struct pci_dev *pdev,
const struct pci_device_id *ent)
ret = drm_dev_register(ddev, 0);
if (ret)
- return ret;
+ goto err_poll_fini;
drm_client_setup(ddev, NULL);
return 0;
+
+err_poll_fini:
+ drm_kms_helper_poll_fini(ddev);
+ return ret;
}
static void lsdc_pci_remove(struct pci_dev *pdev)
{
struct drm_device *ddev = pci_get_drvdata(pdev);
+ drm_kms_helper_poll_fini(ddev);
drm_dev_unregister(ddev);
drm_atomic_helper_shutdown(ddev);
}
--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)
