Re: [syzbot] INFO: task hung in port100_probe

On Fri, Jul 23, 2021 at 11:05:09AM +0200, Krzysztof Kozlowski wrote:

On 22/07/2021 16:47, Alan Stern wrote:

quoted

On Thu, Jul 22, 2021 at 04:20:10PM +0200, Krzysztof Kozlowski wrote:

quoted

Anyone hints where the issue could be?

Here's what I wrote earlier: "It looks like the problem stems from the fact 
that port100_send_frame_async() submits two URBs, but 
port100_send_cmd_sync() only waits for one of them to complete.  The other 
URB may then still be active when the driver tries to reuse it."

I see now you replied this to earlier syzbot report about "URB submitted
while active". Here is a slightly different issue - hung task on waiting
for completion coming from device ack.

However maybe these are both similar or at least come from similar root
cause in the driver.

Exactly what I was thinking.  :-)

quoted

Of course, there may be more than one problem, so we may not be talking 
about the same thing.

Does that help at all?

Thanks, it gives me some ideas to look into although I spent already too
much time on this old driver. I doubt it has any users so maybe better
to mark it as BROKEN...

Whatever you think is best.  I know nothing about port100.

Alan Stern