> -----Original Message----- > From: Sitsofe Wheeler [mailto:sitsofe@xxxxxxxxx] > Sent: Wednesday, August 27, 2014 3:58 PM > To: KY Srinivasan > Cc: Dexuan Cui; Greg Kroah-Hartman; Haiyang Zhang; > devel@xxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx > Subject: Re: [PANIC, hyperv] BUG: unable to handle kernel paging request at > ffff880077800004 (hv_ringbuffer_write) > > On Wed, Aug 27, 2014 at 06:45:55PM +0000, KY Srinivasan wrote: > > > > > -----Original Message----- > > > From: Sitsofe Wheeler [mailto:sitsofe@xxxxxxxxx] > > > Sent: Wednesday, August 27, 2014 9:19 AM > > > > > > > BTW, with the patch below, hyperv_fb can work now, BUT, > > > > *occasionally*, > > > > storvsc_probe() -> ... -> vmbus_open() -> can fail due to > > > > HV_STATUS_INVALID_ALIGNMENT... > > > > > > I applied your new patch on top of KY's pieces (it applied cleanly) > > > and while it doesn't blow up, one warning is printed out and the UP > > > boot seemed to stall after input: TPPS/2 message (but pressing > > > ctrl-alt-delete allows the system to reboot cleanly). > > > > First let me thank you guys for looking into this issue. Looking at > > your dmesg, it looked like storvsc probe failed as Dexuan had seen. > > Since the failure appears to be alignment related, perhaps we could > > test with allocating a page all the time (and getting rid of the > > kmalloc). Sitsofe, here is a patch based on Dexuan's patch. If this > > works, I will probably minimize failure cases by pre-allocating > > per-cpu pages for this.: > > After some modifications to apply on top of your previous patches applying > this latest patch has cured the issues surrounding hyperv_fb issues on boot. > The only issue seen on boot now is similar to > https://lkml.org/lkml/2014/8/19/227 ... That is good to hear. I was under the impression that this issue would be resolved with all the cleanup we have done. The last patch-set I posted earlier today has the fix for vmbus_open bug that Dexuan had identified. If you could try with the BUG_ON elimination patch-set I sent out earlier today with the fix in hv.c that I had sent that would be great. > > How come previous alignment efforts weren't working out? I have chosen to always allocate a page and so alignment won't be an issue. I want to eliminate failure in this path and so, I will most likely do a per-cpu pre-allocation of this buffer. Thank you very much for taking the time to help us debug these issues. Regards, K. Y > > -- > Sitsofe | http://sucs.org/~sits/ _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
