On Wed, Sep 3, 2014 at 12:19 AM, Zbigniew Bodek <zbb@xxxxxxxxxxxx> wrote: > 2014-09-02 9:26 GMT+02:00 Diana Craciun <diana.craciun@xxxxxxxxxxxxx>: >> On 09/01/2014 05:34 PM, Christoffer Dall wrote: >>> >>> On Mon, Sep 01, 2014 at 12:34:09PM +0200, Zbigniew Bodek wrote: >>>> >>>> 2014-09-01 12:16 GMT+02:00 Christoffer Dall >>>> <christoffer.dall@xxxxxxxxxx>: >>>>> >>>>> >>>>> On Monday, September 1, 2014, Zbigniew Bodek <zbb@xxxxxxxxxxxx> wrote: >>>>>> >>>>>> 2014-09-01 11:56 GMT+02:00 Zbigniew Bodek <zbb@xxxxxxxxxxxx>: >>>>>>> >>>>>>> Hello Christopher, >>>>>>> >>>>>>> Please check out my answers in-line. >>>>>>> >>>>>>> Best regards >>>>>>> zbb >>>>>>> >>>>>>> 2014-09-01 11:00 GMT+02:00 Christoffer Dall >>>>>>> <christoffer.dall@xxxxxxxxxx>: >>>>>>>> >>>>>>>> On Tue, Aug 26, 2014 at 12:17:17PM +0200, Zbigniew Bodek wrote: >>>>>>>>> >>>>>>>>> 2014-08-25 21:30 GMT+02:00 Joel Schopp <joel.schopp@xxxxxxx>: >>>>>>>>>> >>>>>>>>>> On 08/25/2014 02:03 PM, Peter Maydell wrote: >>>>>>>>>>> >>>>>>>>>>> On 25 August 2014 19:49, Joel Schopp <joel.schopp@xxxxxxx> wrote: >>>>>>>>>>>> >>>>>>>>>>>> I'm guessing that the patches Peter posted recently might have a >>>>>>>>>>>> positive effect on breakpoints and debugging with gdb. >>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> https://lists.nongnu.org/archive/html/qemu-devel/2014-08/msg01291.html >>>>>>>>>>> >>>>>>>>>>> No, those relate to running a GDB inside the QEMU TCG guest, >>>>>>>>>>> and won't affect an external gdb. What Zbigniew wants to do >>>>>>>>>>> is use the QEMU gdbstub to debug the whole guest. For >>>>>>>>>>> breakpoints to work in that when KVM is enabled requires >>>>>>>>>>> implementing support for breakpoints and the debug >>>>>>>>>>> interface in KVM and then the corresponding support for it >>>>>>>>>>> in QEMU. This is on our todo list (those with cards.linaro.org >>>>>>>>>>> access can find it as VIRT-116) but I don't think anybody's >>>>>>>>>>> working on it right now. >>>>>>>>>>> >>>>>>>>>> Thanks for the clarification. So many todos, so little time. >>>>>>>>> >>>>>>>>> Hello again, >>>>>>>>> >>>>>>>>> Thank you all very much for your answers. >>>>>>>>> Actually I use qemu with GDB as described here (-s -S, etc.), I've >>>>>>>>> just posted the simplest command that I use to trigger the bug. >>>>>>>>> So regarding your answers I would like to ask for some more >>>>>>>>> clarification: >>>>>>>>> * Has anyone encountered/reproduce this problem on your ARM host? >>>>>>>>> * Any suggestion where to look in the KVM source for these kind of >>>>>>>>> problems? >>>>>>>>> * Maybe there is some unstable feature that I could disable in >>>>>>>>> host/guest to narrow this issue? >>>>>>>>> >>>>>>>> Just checking: Are you compiling any of your kernels in Thumb-2 >>>>>>>> mode? >>>>>>>> I believe the 5250 has a hardware bug with Thumb-2 and Hyp mode. >>>>>> >>>>>> No, I am not compiling my kernels in Thumb-2 mode. >>>>>> >>>>>>>> Continuous reboots seems to work fine on my TC2. I can try giving it >>>>>>>> a >>>>>>>> test on an Arndale some time in the near future. Which kernel >>>>>>>> version >>>>>>>> (exact commit) are you using for your host and guest? >>>>>> >>>>>> I used v3.17-rc1 which is: 7d1311b93e58ed55f3a31cc8f94c4b8fe988a2b9 >>>>> >>>>> >>>>> Ok, and when you say reboot, do you mean executing 'reboot' in the guest >>>>> or >>>>> are you shutting down the qemu process completely and starting a new VM? >>>>> Do >>>>> you run any specific workload in the VM? >>>>> >>>>> >>>> I mean to execute 'reboot' command in the guest system, not exit and >>>> reset qemu process. >>>> But the issues I encounter can be also triggered when I execute guest >>>> machine for the first time (so without previous reboots). It is >>>> totally random behavior. >>>> I am not running anything in the VM. Just login to busybox/Ubuntu and >>>> reboot. >>>> >>> I just had a loop running on TC2 for hours and it works fine. Likely to >>> be some specific issue with the Arndale board, I'll have a look when I >>> have a chance to configure my board. >> >> >> I saw this behaviour on Arndale board also. When I saw it I was running an >> older kernel so it is not something new. >> >> Diana >> > > Hello, > > Thanks for the confirmation. I've also tried older kernel and the same > problems appear. > > Does anyone have any clues which areas to investigate in order to debug this? > Thank you all for your help. > You should enable the KVM dynamic tracepoints in your host and figure out where the guest gets stuck and if there's any consistency between when it happens. Thanks, -Christoffer _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
