CVE-2022-48796: In the Linux kernel, the following vulnerability has been resolved:  iommu: Fix potential use-after-free during probe  Kasan has reported the following use after free on dev->iommu. when a device probe fails and it is in process of freeing dev->iommu in dev_iommu_free function, a deferred_probe_work_func runs in parallel and tries to access dev->iommu->fwspec in of_iommu_configure path thus causing use after free.  BUG: KASAN: use-after-free in of_iommu_configure+0xb4/0x4a4 Read of size 8 at addr ffffff87a2f1acb8 by task kworker/u16:2/153  Workqueue: events_unbound deferred_probe_work_func Call trace:  dump_backtrace+0x0/0x33c  show_stack+0x18/0x24  dump_stack_lvl+0x16c/0x1e0  print_address_description+0x84/0x39c  __kasan_report+0x184/0x308  kasan_report+0x50/0x78  __asan_load8+0xc0/0xc4  of_iommu_configure+0xb4/0x4a4  of_dma_configure_id+0x2fc/0x4d4  platform_dma_configure+0x40/0x5c  really_probe+0x1b4/0xb74  driver_probe_device+0x11c/0x228  __device_attach_driver+0x14c/0x304  bus_for_each_drv+0x124/0x1b0  __device_attach+0x25c/0x334  device_initial_probe+0x24/0x34  bus_probe_device+0x78/0x134  deferred_probe_work_func+0x130/0x1a8  process_one_work+0x4c8/0x970  worker_thread+0x5c8/0xaec  kthread+0x1f8/0x220  ret_from_fork+0x10/0x18  Allocated by task 1:  ____kasan_kmalloc+0xd4/0x114  __kasan_kmalloc+0x10/0x1c  kmem_cache_alloc_trace+0xe4/0x3d4  __iommu_probe_device+0x90/0x394  probe_iommu_group+0x70/0x9c  bus_for_each_dev+0x11c/0x19c  bus_iommu_probe+0xb8/0x7d4  bus_set_iommu+0xcc/0x13c  arm_smmu_bus_init+0x44/0x130 [arm_smmu]  arm_smmu_device_probe+0xb88/0xc54 [arm_smmu]  platform_drv_probe+0xe4/0x13c  really_probe+0x2c8/0xb74  driver_probe_device+0x11c/0x228  device_driver_attach+0xf0/0x16c  __driver_attach+0x80/0x320  bus_for_each_dev+0x11c/0x19c  driver_attach+0x38/0x48  bus_add_driver+0x1dc/0x3a4  driver_register+0x18c/0x244  __platform_driver_register+0x88/0x9c  init_module+0x64/0xff4 [arm_smmu]  do_one_initcall+0x17c/0x2f0  do_init_module+0xe8/0x378  load_module+0x3f80/0x4a40  __se_sys_finit_module+0x1a0/0x1e4  __arm64_sys_finit_module+0x44/0x58  el0_svc_common+0x100/0x264  do_el0_svc+0x38/0xa4  el0_svc+0x20/0x30  el0_sync_handler+0x68/0xac  el0_sync+0x160/0x180  Freed by task 1:  kasan_set_track+0x4c/0x84  kasan_set_free_info+0x28/0x4c  ____kasan_slab_free+0x120/0x15c  __kasan_slab_free+0x18/0x28  slab_free_freelist_hook+0x204/0x2fc  kfree+0xfc/0x3a4  __iommu_probe_device+0x284/0x394  probe_iommu_group+0x70/0x9c  bus_for_each_dev+0x11c/0x19c  bus_iommu_probe+0xb8/0x7d4  bus_set_iommu+0xcc/0x13c  arm_smmu_bus_init+0x44/0x130 [arm_smmu]  arm_smmu_device_probe+0xb88/0xc54 [arm_smmu]  platform_drv_probe+0xe4/0x13c  really_probe+0x2c8/0xb74  driver_probe_device+0x11c/0x228  device_driver_attach+0xf0/0x16c  __driver_attach+0x80/0x320  bus_for_each_dev+0x11c/0x19c  driver_attach+0x38/0x48  bus_add_driver+0x1dc/0x3a4  driver_register+0x18c/0x244  __platform_driver_register+0x88/0x9c  init_module+0x64/0xff4 [arm_smmu]  do_one_initcall+0x17c/0x2f0  do_init_module+0xe8/0x378  load_module+0x3f80/0x4a40  __se_sys_finit_module+0x1a0/0x1e4  __arm64_sys_finit_module+0x44/0x58  el0_svc_common+0x100/0x264  do_el0_svc+0x38/0xa4  el0_svc+0x20/0x30  el0_sync_handler+0x68/0xac  el0_sync+0x160/0x180  Fix this by setting dev->iommu to NULL first and then freeing dev_iommu structure in dev_iommu_free function.