CVE-2022-50714: 
Linux Kernel vulnerability analysis and mitigation

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

wifi: mt76: mt7921e: fix rmmod crash in driver reload test

In insmod/rmmod stress test, the following crash dump shows up immediately. The problem is caused by missing mt76_dev in mt7921_pci_remove(). We should make sure the drvdata is ready before probe() finished.

[168.862789] ================================================================== [168.862797] BUG: KASAN: user-memory-access in try_to_grab_pending+0x59/0x480 [168.862805] Write of size 8 at addr 0000000000006df0 by task rmmod/5361 [168.862812] CPU: 7 PID: 5361 Comm: rmmod Tainted: G OE 5.19.0-rc6 #1 [168.862816] Hardware name: Intel(R) Client Systems NUC8i7BEH/NUC8BEB, 05/04/2020 [168.862820] Call Trace: [168.862822] [168.862825] dump_stack_lvl+0x49/0x63 [168.862832] print_report.cold+0x493/0x6b7 [168.862845] kasan_report+0xa7/0x120 [168.862857] kasan_check_range+0x163/0x200 [168.862861] __kasan_check_write+0x14/0x20 [168.862866] try_to_grab_pending+0x59/0x480 [168.862870] __cancel_work_timer+0xbb/0x340 [168.862898] cancel_work_sync+0x10/0x20 [168.862902] mt7921_pci_remove+0x61/0x1c0 [mt7921e] [168.862909] pci_device_remove+0xa3/0x1d0 [168.862914] device_remove+0xc4/0x170 [168.862920] device_release_driver_internal+0x163/0x300 [168.862925] driver_detach+0xc7/0x1a0 [168.862930] bus_remove_driver+0xeb/0x2d0 [168.862935] driver_unregister+0x71/0xb0 [168.862939] pci_unregister_driver+0x30/0x230 [168.862944] mt7921_pci_driver_exit+0x10/0x1b [mt7921e] [168.862949] __x64_sys_delete_module+0x2f9/0x4b0 [168.862968] do_syscall_64+0x38/0x90 [168.862973] entry_SYSCALL_64_after_hwframe+0x63/0xcd

Test steps:

1. insmode
2. do not ifup
3. rmmod quickly (within 1 second)