> Gesendet: Mittwoch, 14. Juli 2021 um 13:18 Uhr > Von: "Yong Wu" <yong.wu@xxxxxxxxxxxx> > Hi Frank, > > Thanks for your report. mt7623 use mtk_iommu_v1.c. > > I will try to reproduce this locally. Hi, as far as i have debugged it dev->iommu_group is NULL, so it crashes on first access (dev_info) drivers/iommu/iommu.c: 923 void iommu_group_remove_device(struct device *dev) 924 { 925 printk(KERN_ALERT "DEBUG: Passed %s %d \n",__FUNCTION__,__LINE__); 926 struct iommu_group *group = dev->iommu_group; 927 struct group_device *tmp_device, *device = NULL; 928 929 printk(KERN_ALERT "DEBUG: Passed %s %d 0x%08x\n",__FUNCTION__,__LINE__,(unsigned int)group); 930 dev_info(dev, "Removing from iommu group %d\n", group->id); regards Frank