Re: [PATCH] qla2xxx: Fix NULL pointer deref in QLA interrupt

["Bruno Prémont" <bonbons@linux-vserver.org>]

On Mon, 11 Jul 2016 09:30:30 +0200 Thorsten Leemhuis wrote:
> Bruno Prémont wrote on 11.07.2016 09:17:
> > On Fri, 8 Jul 2016 09:27:18 +0200 Thorsten Leemhuis wrote:  
> >> Bruno Prémont wrote on 30.06.2016 17:00:  
> >> > In qla24xx_process_response_queue() rsp->msix->cpuid may trigger NULL
> >> > pointer dereference when rsp->msix is NULL:
> >> > […]
> >> > The affected code was introduced by commit cdb898c52d1dfad4b4800b83a58b3fe5d352edde
> >> > (qla2xxx: Add irq affinity notification).
> >> > 
> >> > Only dereference rsp->msix when it has been set so the machine can boot
> >> > fine. Possibly rsp->msix is unset because:
> >> > [    3.479679] qla2xxx [0000:00:00.0]-0005: : QLogic Fibre Channel HBA Driver: 8.07.00.33-k.
> >> > [    3.481839] qla2xxx [0000:13:00.0]-001d: : Found an ISP2432 irq 17 iobase 0xffffc90000038000.
> >> > [    3.484081] qla2xxx [0000:13:00.0]-0035:0: MSI-X; Unsupported ISP2432 (0x2, 0x3).
> >> > [    3.485804] qla2xxx [0000:13:00.0]-0037:0: Falling back-to MSI mode -258.
> >> > [    3.890145] scsi host0: qla2xxx
> >> > [    3.891956] qla2xxx [0000:13:00.0]-00fb:0: QLogic QLE2460 - PCI-Express Single Channel 4Gb Fibre Channel HBA.
> >> > [    3.894207] qla2xxx [0000:13:00.0]-00fc:0: ISP2432: PCIe (2.5GT/s x4) @ 0000:13:00.0 hdma+ host#=0 fw=7.03.00 (9496).
> >> > [    5.714774] qla2xxx [0000:13:00.0]-500a:0: LOOP UP detected (4 Gbps).    
> >> 
> >> Bruno: Does that mean you actually tested that patch and it fixed the
> >> problem for you? It looks like it, but there is some confusion about it;
> >> that's one of the reasons why this patch didn't get any further yet
> >> afaics, so a quick clarification might help to finally get this fixed
> >> properly in mainline and stable.  
> > Yes, it does fix the Oops for me.  
> 
> Thx for the feedback. The patch hit mainline late last week (it's
> included in rc7) and should hopefully make it to the stable trees in a
> week or two.

I got the queued notification from James last week and kept an eye
at the state on patchwork before that.

> > I did not analyze the reason why rsp->msix is NULL (no idea if
> > it remains NULL forever on my hardware) - I just extracted messages
> > from qla driver shown during boot which seem to indicate a possible
> > reason why msix is NULL.
> > Further analysis should be done by someone with better knowledge of qla
> > driver than mine though I would be happy to perform tests.  
> 
> I have no idea about the details, but in case you missed it, this
> discussion might have some more relevant details:
> http://thread.gmane.org/gmane.linux.kernel/2247804/focus=2250727

I didn't see that thread, though it does have some insight.
Thanks for the reference!

Bruno

> Cheers, Thorsten