Re: [usb-storage] [PATCH] usb: storage: Fix a possible data race in uas_queuecommand_lck

From: Jia-Ju Bai
Date: Tue May 08 2018 - 04:40:04 EST




On 2018/5/8 16:27, Oliver Neukum wrote:
Am Dienstag, den 08.05.2018, 15:47 +0800 schrieb Jia-Ju Bai:
The write operations to "cmnd->result" and "cmnd->scsi_done"
are protected by the lock on line 642-643, but the write operations
to these data on line 634-635 are not protected by the lock.
Thus, there may exist a data race for "cmnd->result"
and "cmnd->scsi_done".
No,

the write operations need no lock. The low level driver at this point
owns the command. We cannot race with abort() for a command within
queuecommand(). We take the lock where we take it to protect
dev->resetting.

I don't see why the scope of the lock would need to be enlarged.

Okay, thanks for your reply and explanation.


Best wishes,
Jia-Ju Bai