Re: Panic when cpu hot-remove

[Joerg Roedeljoro <joro@8bytes.org>]

On Wed, Jun 17, 2015 at 10:42:49AM +0000, 范冬冬 wrote:
> Hi maintainer,
> 
> We found a problem that a panic happen when cpu was hot-removed. We also trace the problem according to the calltrace information.
> An endless loop happen because value head is not equal to value tail forever in the function qi_check_fault( ).
> The location code is as follows:
> 
> 
> do {
>         if (qi->desc_status[head] == QI_IN_USE)
>         qi->desc_status[head] = QI_ABORT;
>         head = (head - 2 + QI_LENGTH) % QI_LENGTH;
>     } while (head != tail);

Hmm, this code interates only over every second QI descriptor, and tail
probably points to a descriptor that is not iterated over.

Jiang, can you please have a look?


	Joerg