Re: Revert "aio: fix aio request leak when events are reaped by user space"

From: Benjamin LaHaise
Date: Mon Aug 25 2014 - 11:12:03 EST


On Mon, Aug 25, 2014 at 03:06:12PM +0000, Elliott, Robert (Server Storage) wrote:
> Using this version of the patch, I ran into this crash after 36
> hours of scsi-mq testing over the weekend.
...
>
> local_irq_save(flags);
> kcpu = this_cpu_ptr(ctx->cpu);
> kcpu->reqs_available += nr;
>
> while (kcpu->reqs_available >= ctx->req_batch * 2) {

This crash is not particularly useful, as that version of the patch was
buggy and could result in reqs_available getting corrupted (ie, it could
overflow), which could lead to the system getting stuck for a significant
amount of time in put_reqs_available(). In other words, the crash you
reported matches the known problem with that patch.

-ben
--
"Thought is the essence of where you are now."
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