Re: [drivers/usb/usbip] BUG: corrupted list in vep_queue

[Shuah Khan <skhan@linuxfoundation.org>]

On 10/11/24 11:05, Shuah Khan wrote:
> On 10/11/24 10:21, Chenyuan Yang wrote:
>> Hi Greg,
>>
>> I'm curious about the best approach to fix this issue. I'm unsure if
>> adding a spinlock or mutex around the code would be good to ensure
>> that only one thread can modify the list at a time (then fix this
>> issue).
>>
>> Alternatively, we could check if the entry is already in the list
>> within the vep_queue function:
>> ```
>> if (!list_empty(&new_entry->list)) {
>>      // Entry is already in the list, handle it (e.g., log an error or ignore)
>>      return -EEXIST; // Or another appropriate error code
>> }
>>
> 
> vep_queue() function is holding udc lock when it updates
> the status and calls list_add_tail(). vep_dequeue() does
> the same.
> 
> vep_free_request() doesn't see to hold the udc lock. I will
> tale a look at this a bit more and get back to you on the
> best approach. My guess is that the fix will be in another
> function such as vep_free_request() - at the moment - that
> routine is the one I suspect.
> 
> 

Can you try adding udc lock hold in vep_free_request() and see
if the problem persists?

thanks,
-- Shuah