Re: [qemu64,+smep,+smap] Kernel panic - not syncing: No working init found.
On 02/13/2014 04:45 AM, Fengguang Wu wrote: Greetings, I find that when running qemu-system-x86_64 -cpu qemu64,+smep,+smap Some kernels will 100% produce this error, where the error code -13,-14 are -EACCES and -EFAULT: Any ideas? I notice this is a non-SMAP kernel: # CONFIG_X86_SMAP is not set If the kernel turns on SMAP in CR4 even though SMAP isn't enabled in the kernel, that is a kernel bug. If Qemu enforces SMAP even if it is turned off in CR4, that would be a Qemu bug. I have reproduced the failure locally and an am considering both possibilities now. -hpa -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [qemu64,+smep,+smap] Kernel panic - not syncing: No working init found.
On 02/13/2014 06:55 AM, H. Peter Anvin wrote: On 02/13/2014 04:45 AM, Fengguang Wu wrote: Greetings, I find that when running qemu-system-x86_64 -cpu qemu64,+smep,+smap Some kernels will 100% produce this error, where the error code -13,-14 are -EACCES and -EFAULT: Any ideas? I notice this is a non-SMAP kernel: # CONFIG_X86_SMAP is not set If the kernel turns on SMAP in CR4 even though SMAP isn't enabled in the kernel, that is a kernel bug. If Qemu enforces SMAP even if it is turned off in CR4, that would be a Qemu bug. I have reproduced the failure locally and an am considering both possibilities now. So we do turn on the bit in CR4 even with SMAP compiled out. This is a bug. However, I still get the same failure even with that bug fixed (and qemu info registers verify that it is, indeed, not set) so I'm wondering if there is a bug in Qemu as well. However, staring at the code in Qemu I don't see where that bug would be... -hpa -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [qemu64,+smep,+smap] Kernel panic - not syncing: No working init found.
On 02/13/2014 06:55 AM, H. Peter Anvin wrote: On 02/13/2014 04:45 AM, Fengguang Wu wrote: Greetings, I find that when running qemu-system-x86_64 -cpu qemu64,+smep,+smap Some kernels will 100% produce this error, where the error code -13,-14 are -EACCES and -EFAULT: Any ideas? I notice this is a non-SMAP kernel: # CONFIG_X86_SMAP is not set If the kernel turns on SMAP in CR4 even though SMAP isn't enabled in the kernel, that is a kernel bug. If Qemu enforces SMAP even if it is turned off in CR4, that would be a Qemu bug. I have reproduced the failure locally and an am considering both possibilities now. No, it is simply a second kernel bug. I have patches for both and will push them momentarily. -hpa -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
