Re: [usb-storage] [PATCH] usb: storage: Fix a possible data race in uas_queuecommand_lck
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 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [usb-storage] [PATCH] usb: storage: Fix a possible data race in uas_queuecommand_lck
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. Regards Oliver > 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 Nacked-by: Oliver Neukum -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
