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

From: Oliver Neukum
Date: Tue May 08 2018 - 04:34:37 EST

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".


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

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


> To fix this data race, the write operations on line 634-635
> should be also protected by the lock.
> Signed-off-by: Jia-Ju Bai <baijiaju1990@xxxxxxxxx>
Nacked-by: Oliver Neukum <oneukum@xxxxxxxx>