CVE-2022-48826

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

drm/vc4: Fix deadlock on DSI device attach error

DSI device attach to DSI host will be done with host devices lock held.

Un-registering host in device attach error path (ex: probe retry) will result in deadlock with below call trace and non operational DSI display.

Startup Call trace: [ 35.043036] rt_mutex_slowlock.constprop.21+0x184/0x1b8 [ 35.043048] mutex_lock_nested+0x7c/0xc8 [ 35.043060] device_del+0x4c/0x3e8 [ 35.043075] device_unregister+0x20/0x40 [ 35.043082] mipi_dsi_remove_device_fn+0x18/0x28 [ 35.043093] device_for_each_child+0x68/0xb0 [ 35.043105] mipi_dsi_host_unregister+0x40/0x90 [ 35.043115] vc4_dsi_host_attach+0xf0/0x120 [vc4] [ 35.043199] mipi_dsi_attach+0x30/0x48 [ 35.043209] tc358762_probe+0x128/0x164 [tc358762] [ 35.043225] mipi_dsi_drv_probe+0x28/0x38 [ 35.043234] really_probe+0xc0/0x318 [ 35.043244] __driver_probe_device+0x80/0xe8 [ 35.043254] driver_probe_device+0xb8/0x118 [ 35.043263] __device_attach_driver+0x98/0xe8 [ 35.043273] bus_for_each_drv+0x84/0xd8 [ 35.043281] __device_attach+0xf0/0x150 [ 35.043290] device_initial_probe+0x1c/0x28 [ 35.043300] bus_probe_device+0xa4/0xb0 [ 35.043308] deferred_probe_work_func+0xa0/0xe0 [ 35.043318] process_one_work+0x254/0x700 [ 35.043330] worker_thread+0x4c/0x448 [ 35.043339] kthread+0x19c/0x1a8 [ 35.043348] ret_from_fork+0x10/0x20

Shutdown Call trace: [ 365.565417] Call trace: [ 365.565423] __switch_to+0x148/0x200 [ 365.565452] __schedule+0x340/0x9c8 [ 365.565467] schedule+0x48/0x110 [ 365.565479] schedule_timeout+0x3b0/0x448 [ 365.565496] wait_for_completion+0xac/0x138 [ 365.565509] __flush_work+0x218/0x4e0 [ 365.565523] flush_work+0x1c/0x28 [ 365.565536] wait_for_device_probe+0x68/0x158 [ 365.565550] device_shutdown+0x24/0x348 [ 365.565561] kernel_restart_prepare+0x40/0x50 [ 365.565578] kernel_restart+0x20/0x70 [ 365.565591] __do_sys_reboot+0x10c/0x220 [ 365.565605] __arm64_sys_reboot+0x2c/0x38 [ 365.565619] invoke_syscall+0x4c/0x110 [ 365.565634] el0_svc_common.constprop.3+0xfc/0x120 [ 365.565648] do_el0_svc+0x2c/0x90 [ 365.565661] el0_svc+0x4c/0xf0 [ 365.565671] el0t_64_sync_handler+0x90/0xb8 [ 365.565682] el0t_64_sync+0x180/0x184

Weakness

The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors.

Affected Software

Extended Description

Locking is a type of synchronization behavior that ensures that multiple independently-operating processes or threads do not interfere with each other when accessing the same resource. All processes/threads are expected to follow the same steps for locking. If these steps are not followed precisely - or if no locking is done at all - then another process/thread could modify the shared resource in a way that is not visible or predictable to the original process. This can lead to data or memory corruption, denial of service, etc.

Potential Mitigations

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/25.html
• https://cwe.mitre.org/data/definitions/26.html
• https://cwe.mitre.org/data/definitions/27.html

References

• https://git.kernel.org/stable/c/0a3d12ab5097b1d045e693412e6b366b7e82031b
• https://git.kernel.org/stable/c/770d1ba9a8201ce9bee0946eb03746449b6f3b80
• https://git.kernel.org/stable/c/dddd832f35096fbc5004e3a7e58fb4d2cefb8deb