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charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 21/09/26 07:12, Shrikanth Hegde wrote: > Hi Christian. > > On 9/20/26 6:34 PM, Christian Zigotzky wrote: >> On 09/20/2026 01:49 PM, Christian Zigotzky wrote: >>> On 09/18/2026 09:10 AM, Michal Suchánek wrote: >>>> On Fri, Sep 18, 2026 at 04:39:57AM +0200, Christian Zigotzky wrote: >>>>> On 17/09/26 16:15, Shrikanth Hegde wrote: >>>>>> Hi Michal, >>>>>> >>>>>>>> Give it a try. >>>>>>>> >>>>>>>> I am suspecting both lockup, stack corruptions are secondary >>>>>>>> symptoms here. >>>>>>>> While recreate, I have different type of traces. >>>>>>> Yes, it does work for the crash I see. >>>>>> Thanks. Give me sometime to see further on that. Didn't get any time >>>>>> today. >>>>>> >>>>>>> However, we hijacked the report >>>>>>> of KVM locking up on FSL Cyrus+, and that is likely a different >>>>>>> problem >>>>>>> still not addressed. >>>>>>> >>>>>> Ah, that's what you meant. Yes, i still don't know where FSL >>>>>> Cyrus+ is >>>>>> stuck. >>>>>> >>>>>> I would need help from FSL Cyrus+ to get some logs or is there a >>>>>> way we >>>>>> can spin of >>>>>> a QEMU guest of it? We should have the log to start somewhere. >>>>>> >>>>>> >>>>> It's difficult to get a log because it freezes and can't write any >>>>> error >>>>> messages to the log files. This bug is very old. We had this issue >>>>> some >>>>> years ago but we was able to disable PREEMPT because we don't need >>>>> it. >>>> I would expect serial console and sysrq could give something, >>>> depending >>>> on how much of the kernel is frozen. >>>> >>>> Thanks >>>> >>>> Michal >>> Here is a serial log: >>> https://github.com/user-attachments/files/32433586/e5500_preempt_putty.log >>> > > Thanks Michal for helping to get the traces. > >> Another serial log with pcie_ports=compat: >> https://github.com/user-attachments/files/32434487/e5500_preempt_pcie_ports_compat_putty.log >> >> > > I see it is mostly busy with printing > WARNING: at .enable_kernel_fp+0x30/0x78, CPU#3: qemu-system-ppc/4884 > > The path seems to be same also. > > [c000000085ca7700] [c00000000005de84] .kvmppc_load_guest_fp+0x30/0x80 > [c000000085ca7780] [c00000000005f2a0] .kvmppc_handle_exit+0x5bc/0x5cc > [c000000085ca7830] [c00000000006204c] .kvmppc_resume_host+0xb8/0x10c > > > Does below help to boot or make it stable? > --- >  arch/powerpc/kvm/booke.c | 9 ++++++++- >  1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c > index 13ad4cf5fa71..d4be7a306bfc 100644 > --- a/arch/powerpc/kvm/booke.c > +++ b/arch/powerpc/kvm/booke.c > @@ -1404,10 +1404,17 @@ int kvmppc_handle_exit(struct kvm_vcpu *vcpu, > unsigned int exit_nr) >          if (s <= 0) >              r = (s << 2) | RESUME_HOST | (r & RESUME_FLAG_NV); >          else { > -            /* interrupts now hard-disabled */ > +            /* > +             * interrupts now hard-disabled. i.e EE=0 > +             * But irqs_disabled relies on PACA entries > +             * and fixup below enables it. > +             * So irqs_disabled == false > +             */ >              kvmppc_fix_ee_before_entry(); > +            preempt_disable(); >              kvmppc_load_guest_fp(vcpu); >              kvmppc_load_guest_altivec(vcpu); > +            preempt_enable_no_resched(); >          } >      } > > Hi, Thanks a lot for your patch! I patched the 7.3-rc4 kernel sources with your new patch and compiled the kernel again yesterday. [1] Unfortunately, the issue still exists. I tested it with a guest kernel with and without preempt support. Cheers, Christian [1] https://github.com/chzigotzky/kernels/releases/tag/v7.3.0-rc4-2-preempt -- Sent with BrassMonkey 34.3.2.1 (https://github.com/chzigotzky/Web-Browsers-and-Suites-for-Linux-PPC/releases/tag/BrassMonkey_34.3.2.1)