CVE-2022-50735

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

wifi: mt76: do not run mt76u_status_worker if the device is not running

Fix the following NULL pointer dereference avoiding to run mt76u_status_worker thread if the device is not running yet.

KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 0 PID: 98 Comm: kworker/u2:2 Not tainted 5.14.0+ #78 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014 Workqueue: mt76 mt76u_tx_status_data RIP: 0010:mt76x02_mac_fill_tx_status.isra.0+0x82c/0x9e0 Code: c5 48 b8 00 00 00 00 00 fc ff df 80 3c 02 00 0f 85 94 01 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8b 34 24 4c 89 f2 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 89 01 00 00 41 8b 16 41 0f b7 RSP: 0018:ffffc900005af988 EFLAGS: 00010246 RAX: dffffc0000000000 RBX: ffffc900005afae8 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff832fc661 RDI: ffffc900005afc2a RBP: ffffc900005afae0 R08: 0000000000000001 R09: fffff520000b5f3c R10: 0000000000000003 R11: fffff520000b5f3b R12: ffff88810b6132d8 R13: 000000000000ffff R14: 0000000000000000 R15: ffffc900005afc28 FS: 0000000000000000(0000) GS:ffff88811aa00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa0eda6a000 CR3: 0000000118f17000 CR4: 0000000000750ef0 PKRU: 55555554 Call Trace: mt76x02_send_tx_status+0x1d2/0xeb0 mt76x02_tx_status_data+0x8e/0xd0 mt76u_tx_status_data+0xe1/0x240 process_one_work+0x92b/0x1460 worker_thread+0x95/0xe00 kthread+0x3a1/0x480 ret_from_fork+0x1f/0x30 Modules linked in: --[ end trace 8df5d20fc5040f65 ]-- RIP: 0010:mt76x02_mac_fill_tx_status.isra.0+0x82c/0x9e0 Code: c5 48 b8 00 00 00 00 00 fc ff df 80 3c 02 00 0f 85 94 01 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8b 34 24 4c 89 f2 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 89 01 00 00 41 8b 16 41 0f b7 RSP: 0018:ffffc900005af988 EFLAGS: 00010246 RAX: dffffc0000000000 RBX: ffffc900005afae8 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff832fc661 RDI: ffffc900005afc2a RBP: ffffc900005afae0 R08: 0000000000000001 R09: fffff520000b5f3c R10: 0000000000000003 R11: fffff520000b5f3b R12: ffff88810b6132d8 R13: 000000000000ffff R14: 0000000000000000 R15: ffffc900005afc28 FS: 0000000000000000(0000) GS:ffff88811aa00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa0eda6a000 CR3: 0000000118f17000 CR4: 0000000000750ef0 PKRU: 55555554

Moreover move stat_work schedule out of the for loop.