[Bug 602539] Re: qemu-system-x86_64 segfaults if using -no-kvm with -m 4096 or greater

[Serge Hallyn]

** Description changed:

  Binary package hint: qemu-kvm
  
  Latest Ubuntu 10.04 amd64.
  
  I have a FreeBSD guest I had running quite slowly with the kvm-intel
  module loaded, so I shut down the guest, and passed the -no-kvm flag to
  kvm.
  
  Much to my surprise, I experienced an immediate segmentation fault:
  $ qemu-system-x86_64 -no-kvm -vnc :0 -hda fbsd_dev -m 4096
  pci_add_option_rom: failed to find romfile "pxe-rtl8139.bin"
  Segmentation fault (core dumped)
  
  In contrast:
  $ qemu-system-x86_64 -no-kvm -vnc :0 -hda fbsd_dev -m 4095
  pci_add_option_rom: failed to find romfile "pxe-rtl8139.bin"
  [runs happily forever]
  
  I'm presuming this is some mishandled behavior of qemu having a limit of
  memory being < 4096m when not using VT bits or somesuch, but it was
  quite disruptive, and it didn't occur to me to try varying the memory
  amount for most of a day.
  
  ProblemType: Bug
  DistroRelease: Ubuntu 10.04
  Package: qemu-kvm 0.12.3+noroms-0ubuntu9
  ProcVersionSignature: Ubuntu 2.6.32-22.36-generic 2.6.32.11+drm33.2
  Uname: Linux 2.6.32-22-generic x86_64
  NonfreeKernelModules: nvidia
  Architecture: amd64
  Date: Wed Jul  7 00:32:52 2010
  InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release amd64 (20100427.1)
  KvmCmdLine: Error: command ['ps', '-C', 'kvm', '-F'] failed with exit code 1: UID        PID  PPID  C    SZ   RSS PSR STIME TTY          TIME CMD
  MachineType: Dell Inc. Precision WorkStation T5500
  ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.32-22-generic root=/dev/mapper/root-slash ro quiet splash
  ProcEnviron:
-  LANG=en_US.UTF-8
-  SHELL=/bin/bash
+  LANG=en_US.UTF-8
+  SHELL=/bin/bash
  SourcePackage: qemu-kvm
  dmi.bios.date: 04/12/2010
  dmi.bios.vendor: Dell Inc.
  dmi.bios.version: A05
  dmi.board.name: 0CRH6C
  dmi.board.vendor: Dell Inc.
  dmi.board.version: A00
  dmi.chassis.type: 7
  dmi.chassis.vendor: Dell Inc.
  dmi.modalias: dmi:bvnDellInc.:bvrA05:bd04/12/2010:svnDellInc.:pnPrecisionWorkStationT5500:pvr:rvnDellInc.:rn0CRH6C:rvrA00:cvnDellInc.:ct7:cvr:
  dmi.product.name: Precision WorkStation T5500
  dmi.sys.vendor: Dell Inc.
+ 
+ IMPACT: Specifying too much memory for guest causes a segfault instead of an
+ error message.
+ 
+ FIX: A patch, taken from upstream, which detects the error condition and prints
+ an error message (and exits) instead of continuing and segfaulting.
+ 
+ PATCH: can be seen at
+ https://code.launchpad.net/~serge-hallyn/ubuntu/lucid/qemu-kvm/fix-4096/+merge/29592
+ 
+ TO REPRODUCE: see the detailed incantation above.
+ 
+ REGRESSION POTENTIAL: Only one location in the code is patched, and simply
+ 	catches the pathological condition.  There should be no regression.

-- 
qemu-system-x86_64 segfaults if using -no-kvm with -m 4096 or greater
https://bugs.launchpad.net/bugs/602539
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