Hello Konrad Dybcio,
Commit 5a903a44a984 ("drm/msm/a6xx: Introduce GMU wrapper support")
from Jun 16, 2023 (linux-next), leads to the following Smatch static
checker warning:
drivers/gpu/drm/msm/adreno/a6xx_gmu.c:1844 a6xx_gmu_wrapper_init()
warn: 'gmu->cxpd' can also be NULL
drivers/gpu/drm/msm/adreno/a6xx_gmu.c
1790 int a6xx_gmu_wrapper_init(struct a6xx_gpu *a6xx_gpu, struct device_node *node)
1791 {
1792 struct platform_device *pdev = of_find_device_by_node(node);
1793 struct a6xx_gmu *gmu = &a6xx_gpu->gmu;
1794 int ret;
1795
1796 if (!pdev)
1797 return -ENODEV;
1798
1799 gmu->dev = &pdev->dev;
1800
1801 ret = of_dma_configure(gmu->dev, node, true);
1802 if (ret)
1803 return ret;
1804
1805 pm_runtime_enable(gmu->dev);
1806
1807 /* Mark legacy for manual SPTPRAC control */
1808 gmu->legacy = true;
1809
1810 /* Map the GMU registers */
1811 gmu->mmio = a6xx_gmu_get_mmio(pdev, "gmu");
1812 if (IS_ERR(gmu->mmio)) {
1813 ret = PTR_ERR(gmu->mmio);
1814 goto err_mmio;
1815 }
1816
1817 gmu->cxpd = dev_pm_domain_attach_by_name(gmu->dev, "cx");
dev_pm_domain_attach_by_name() sure seemse like it can return NULL.
1818 if (IS_ERR(gmu->cxpd)) {
1819 ret = PTR_ERR(gmu->cxpd);
1820 goto err_mmio;
1821 }
1822
1823 if (!device_link_add(gmu->dev, gmu->cxpd, DL_FLAG_PM_RUNTIME)) {
If it did then device_link_add() then this would fail
1824 ret = -ENODEV;
1825 goto detach_cxpd;
1826 }
1827
1828 init_completion(&gmu->pd_gate);
1829 complete_all(&gmu->pd_gate);
1830 gmu->pd_nb.notifier_call = cxpd_notifier_cb;
1831
1832 /* Get a link to the GX power domain to reset the GPU */
1833 gmu->gxpd = dev_pm_domain_attach_by_name(gmu->dev, "gx");
1834 if (IS_ERR(gmu->gxpd)) {
1835 ret = PTR_ERR(gmu->gxpd);
1836 goto err_mmio;
1837 }
1838
1839 gmu->initialized = true;
1840
1841 return 0;
1842
1843 detach_cxpd:
--> 1844 dev_pm_domain_detach(gmu->cxpd, false);
^^^^^^^^^
And this would crash.
1845
1846 err_mmio:
1847 iounmap(gmu->mmio);
1848
1849 /* Drop reference taken in of_find_device_by_node */
1850 put_device(gmu->dev);
1851
1852 return ret;
1853 }
regards,
dan carpenter
