Re: [Qemu-devel] ahci: crash after duplicate bh registration

[Alexander Graf]

On 05/09/2011 04:26 PM, Kevin Wolf wrote:
> Am 09.05.2011 16:12, schrieb Alexander Graf:
> > On 05/08/2011 09:10 PM, Jan Kiszka wrote:
> > > Hi Alex,
> > >
> > > I've seen crashes caused by ahci_check_cmd_bh unregistering a NULL bh.
> > > It looks like ahci_dma_set_inactive can a called while there is already
> > > a bh hanging around. Patch below cures the issue, but I have no clue if
> > > such an invocation order is valid at all.
> > It's certainly guest triggerable, so yes, let's check here.
> >
> > Acked-by: Alexander Graf<address@hidden>
> Yes, the change makes sense to me. Please resend this as a proper patch,
> Jan.
>
> However, I still think Jan's question is valid: Is the AHCI emulation
> supposed to run multiple DMA requests at once using the core.c
> functions? I'd find it surprising if this actually worked well.

Not through the IDE core, no. There it can process a queue of IDE 
commands after each other or do NCQ, but that goes a different code 
patch, can do multiple requests at once though.

I'm not sure how this got triggered.


Alex