[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] HVM domains crash after upgrade from XEN 4.5.1 to 4.5.2
Am 19.11.15 um 00:17 schrieb Andrew Cooper: On 18/11/2015 22:51, Atom2 wrote:Am 17.11.15 um 00:10 schrieb Atom2: [big snip] Done. Please find the xl dmesg output attached to this mail. I guess this time it is really what you were expecting. Whether it does make sense though, might be a different issue. But I am confident in your abilities to figure out what's going on.Hi Andrew, as promised I have again tried with a debug build and the results are very mixed. I initially tried to better understand what the debug USE flag actually does in gentoo and my understanding (after reading the so called ebuilds) is now that the XEN hypervisor will be built by adding a gcc option of "debug=y" - and that's what should compile a debug build - right?Yes indeed.So I went on and again enabled the debug USE flag plus gdb symbols and rebuilt the hypervisor in the hope that this created a valid and working debug build. It, however, seems there's another problem lurking somewhere which only manifests itself when I boot from the debug build of the hypervisor.You did manage to get at least one decent log from a properly debugbuild. However, all we need is the hvm_debug output. This patch: ---8<--- diff --git a/xen/include/asm-x86/hvm/support.h b/xen/include/asm-x86/hvm/support.h index 05ef5c5..7a8fbb5 100644 --- a/xen/include/asm-x86/hvm/support.h +++ b/xen/include/asm-x86/hvm/support.h @@ -28,7 +28,7 @@ #define HVM_DELIVER_NO_ERROR_CODE -1 -#ifndef NDEBUG +#if 1 #define DBG_LEVEL_0 (1 << 0) #define DBG_LEVEL_1 (1 << 1) #define DBG_LEVEL_2 (1 << 2) ---8<--- Will enable hvm_debug in a non-debug build of hypervisor. Can you try that please? I haven't done that yet as this will again require a re-compile of the non-working debug build. I'll probably give that a try tomorrow.The system crashes early on with a DOUBLE FAULT in doIRQ - we have had this already earlier in that thread. I am however a step further as the disass in gdb now seems to provide not just an empty page full of NULL values but rather something that might give you a hint why it crashes that early on: Please see the attached disass file (doIRQ) together with the serial console output (serial.dbg). The old NULL value file was probably because I did not include gdb symbols in the debug build at that time - my bad.The fact that it is completely consistent is useful from a debugging point of view. The disassembly of do_IRQ now looks like a plausible function, but the consistently faulting address has no plausible way of generating a double fault. I suspect therefore that something has caused memory corruption in Xen .text section. As an experiment, could you try booting with the minimum available command line options, which look to be just "com1=115200,8n1,0x3f8,4 console=com1,vga dom0_mem=4G,max:4G" to see whether it is an interaction of the options you have enabled. If the issue still reproduces, I will rework the previous debugging patch I gave you to definitely dump the actual code being run at the time of the fault. ~Andrew Thanks Atom2 Attachment:
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