Re: Panic when cpu hot-remove

From: Joerg Roedeljoro
Date: Wed Jun 17 2015 - 07:52:47 EST

On Wed, Jun 17, 2015 at 10:42:49AM +0000, èåå 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?


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