drm/meson: reorder driver deinit sequence to fix use-after-free bug
CVE: CVE-2022-50378
Component: kernel
Severity: None
Release date: 2022-01-01T00:00:00+00:00

In the Linux kernel, the following vulnerability has been resolved:

drm/meson: reorder driver deinit sequence to fix use-after-free bug

Unloading the driver triggers the following KASAN warning:

[  +0.006275] =============================================================
[  +0.000029] BUG: KASAN: use-after-free in __list_del_entry_valid+0xe0/0x1a0
[  +0.000026] Read of size 8 at addr ffff000020c395e0 by task rmmod/2695

[  +0.000019] CPU: 5 PID: 2695 Comm: rmmod Tainted: G         C O      5.19.0-rc6-lrmbkasan+ #1
[  +0.000013] Hardware name: Hardkernel ODROID-N2Plus (DT)
[  +0.000008] Call trace:
[  +0.000007]  dump_backtrace+0x1ec/0x280
[  +0.000013]  show_stack+0x24/0x80
[  +0.000008]  dump_stack_lvl+0x98/0xd4
[  +0.000011]  print_address_description.constprop.0+0x80/0x520
[  +0.000011]  print_report+0x128/0x260
[  +0.000007]  kasan_report+0xb8/0xfc
[  +0.000008]  __asan_report_load8_noabort+0x3c/0x50
[  +0.000010]  __list_del_entry_valid+0xe0/0x1a0
[  +0.000009]  drm_atomic_private_obj_fini+0x30/0x200 [drm]
[  +0.000172]  drm_bridge_detach+0x94/0x260 [drm]
[  +0.000145]  drm_encoder_cleanup+0xa4/0x290 [drm]
[  +0.000144]  drm_mode_config_cleanup+0x118/0x740 [drm]
[  +0.000143]  drm_mode_config_init_release+0x1c/0x2c [drm]
[  +0.000144]  drm_managed_release+0x170/0x414 [drm]
[  +0.000142]  drm_dev_put.part.0+0xc0/0x124 [drm]
[  +0.000143]  drm_dev_put+0x20/0x30 [drm]
[  +0.000142]  meson_drv_unbind+0x1d8/0x2ac [meson_drm]
[  +0.000028]  take_down_aggregate_device+0xb0/0x160
[  +0.000016]  component_del+0x18c/0x360
[  +0.000009]  meson_dw_hdmi_remove+0x28/0x40 [meson_dw_hdmi]
[  +0.000015]  platform_remove+0x64/0xb0
[  +0.000009]  device_remove+0xb8/0x154
[  +0.000009]  device_release_driver_internal+0x398/0x5b0
[  +0.000009]  driver_detach+0xac/0x1b0
[  +0.000009]  bus_remove_driver+0x158/0x29c
[  +0.000009]  driver_unregister+0x70/0xb0
[  +0.000008]  platform_driver_unregister+0x20/0x2c
[  +0.000008]  meson_dw_hdmi_platform_driver_exit+0x1c/0x30 [meson_dw_hdmi]
[  +0.000012]  __do_sys_delete_module+0x288/0x400
[  +0.000011]  __arm64_sys_delete_module+0x5c/0x80
[  +0.000009]  invoke_syscall+0x74/0x260
[  +0.000009]  el0_svc_common.constprop.0+0xcc/0x260
[  +0.000009]  do_el0_svc+0x50/0x70
[  +0.000007]  el0_svc+0x68/0x1a0
[  +0.000012]  el0t_64_sync_handler+0x11c/0x150
[  +0.000008]  el0t_64_sync+0x18c/0x190

[  +0.000018] Allocated by task 0:
[  +0.000007] (stack is not available)

[  +0.000011] Freed by task 2695:
[  +0.000008]  kasan_save_stack+0x2c/0x5c
[  +0.000011]  kasan_set_track+0x2c/0x40
[  +0.000008]  kasan_set_free_info+0x28/0x50
[  +0.000009]  ____kasan_slab_free+0x128/0x1d4
[  +0.000008]  __kasan_slab_free+0x18/0x24
[  +0.000007]  slab_free_freelist_hook+0x108/0x230
[  +0.000011]  kfree+0x110/0x35c
[  +0.000008]  release_nodes+0xf0/0x16c
[  +0.000009]  devres_release_group+0x180/0x270
[  +0.000008]  component_unbind+0x128/0x1e0
[  +0.000010]  component_unbind_all+0x1b8/0x264
[  +0.000009]  meson_drv_unbind+0x1a0/0x2ac [meson_drm]
[  +0.000025]  take_down_aggregate_device+0xb0/0x160
[  +0.000009]  component_del+0x18c/0x360
[  +0.000009]  meson_dw_hdmi_remove+0x28/0x40 [meson_dw_hdmi]
[  +0.000012]  platform_remove+0x64/0xb0
[  +0.000008]  device_remove+0xb8/0x154
[  +0.000009]  device_release_driver_internal+0x398/0x5b0
[  +0.000009]  driver_detach+0xac/0x1b0
[  +0.000009]  bus_remove_driver+0x158/0x29c
[  +0.000008]  driver_unregister+0x70/0xb0
[  +0.000008]  platform_driver_unregister+0x20/0x2c
[  +0.000008]  meson_dw_hdmi_platform_driver_exit+0x1c/0x30 [meson_dw_hdmi]
[  +0.000011]  __do_sys_delete_module+0x288/0x400
[  +0.000010]  __arm64_sys_delete_module+0x5c/0x80
[  +0.000008]  invoke_syscall+0x74/0x260
[  +0.000008]  el0_svc_common.constprop.0+0xcc/0x260
[  +0.000008]  do_el0_svc+0x50/0x70
[  +0.000007]  el0_svc+0x68/0x1a0
[  +0.000009]  el0t_64_sync_handler+0x11c/0x150
[  +0.000009]  el0t_64_sync+0x18c/0x190

[  +0.000014] The buggy address belongs to the object at ffff000020c39000
---truncated---


Remediation: