[Qemu-devel] [Bug 1324727] [NEW] qemu-system-arm segfaults without KVM on ARM

[Peter Chubb]

Public bug reported:

I'm running on Odroid-XU, Debian Jessie armhf
qemu built from today's head d7d3d6092cb7edc75dc49fb90c86dd5425ab4805

sudo  qemu-system-arm -M vexpress-a15 -drive 
if=none,file=arm.img,cache=writeback,id=foo -device virtio-blk-device,drive=foo 
-netdev user,id=user.0 -device virtio-net-device,netdev=user.0 -nographic 
-append 'root=/dev/vda rw console=ttyAMA0 rootwait' -kernel 
/usr/src/build/arm/linux-guest/arch/arm/boot/zImage -dtb a15x2.dtb
audio: Could not init `oss' audio driver
Uncompressing Linux... done, booting the kernel.
Segmentation fault

If I run under GDB, the linux guest instance panics or hangs -- the
behaviour is variable run to run.

If I do:
sudo  qemu-system-arm --enable-kvm -M vexpress-a15 -drive 
if=none,file=arm.img,cache=writeback,id=foo -device virtio-blk-device,drive=foo 
-netdev user,id=user.0 -device virtio-net-device,netdev=user.0 -nographic 
-append 'root=/dev/vda rw console=ttyAMA0 rootwait' -kernel 
/usr/src/build/arm/linux-guest/arch/arm/boot/zImage -dtb a15x2.dtb

then the guest boots as expected.

I tried to get a backtrace by allowinghte SEGV to dump core, and using gdb to 
inspect it:
Core was generated by `qemu-system-arm -M vexpress-a15 -drive 
if=none,file=arm.img,cache=writeback,id='.
Program terminated with signal 11, Segmentation fault.
#0  0xb53399c0 in ?? ()
(gdb) bt
#0  0xb53399c0 in ?? ()
Cannot access memory at address 0x28
#1  0x0016d87e in cpu_tb_exec (
    tb_ptr=0xc786fe90 <Address 0xc786fe90 out of bounds>, cpu=0x24450d8)
    at /mnt/qemu/cpu-exec.c:67
#2  cpu_arm_exec (env=<optimized out>) at /mnt/qemu/cpu-exec.c:642
#3  0x00000000 in ?? ()

** Affects: qemu
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1324727

Title:
  qemu-system-arm segfaults without KVM on ARM

Status in QEMU:
  New

Bug description:
  I'm running on Odroid-XU, Debian Jessie armhf
  qemu built from today's head d7d3d6092cb7edc75dc49fb90c86dd5425ab4805

  sudo  qemu-system-arm -M vexpress-a15 -drive 
if=none,file=arm.img,cache=writeback,id=foo -device virtio-blk-device,drive=foo 
-netdev user,id=user.0 -device virtio-net-device,netdev=user.0 -nographic 
-append 'root=/dev/vda rw console=ttyAMA0 rootwait' -kernel 
/usr/src/build/arm/linux-guest/arch/arm/boot/zImage -dtb a15x2.dtb
  audio: Could not init `oss' audio driver
  Uncompressing Linux... done, booting the kernel.
  Segmentation fault

  If I run under GDB, the linux guest instance panics or hangs -- the
  behaviour is variable run to run.

  If I do:
  sudo  qemu-system-arm --enable-kvm -M vexpress-a15 -drive 
if=none,file=arm.img,cache=writeback,id=foo -device virtio-blk-device,drive=foo 
-netdev user,id=user.0 -device virtio-net-device,netdev=user.0 -nographic 
-append 'root=/dev/vda rw console=ttyAMA0 rootwait' -kernel 
/usr/src/build/arm/linux-guest/arch/arm/boot/zImage -dtb a15x2.dtb

  then the guest boots as expected.

  I tried to get a backtrace by allowinghte SEGV to dump core, and using gdb to 
inspect it:
  Core was generated by `qemu-system-arm -M vexpress-a15 -drive 
if=none,file=arm.img,cache=writeback,id='.
  Program terminated with signal 11, Segmentation fault.
  #0  0xb53399c0 in ?? ()
  (gdb) bt
  #0  0xb53399c0 in ?? ()
  Cannot access memory at address 0x28
  #1  0x0016d87e in cpu_tb_exec (
      tb_ptr=0xc786fe90 <Address 0xc786fe90 out of bounds>, cpu=0x24450d8)
      at /mnt/qemu/cpu-exec.c:67
  #2  cpu_arm_exec (env=<optimized out>) at /mnt/qemu/cpu-exec.c:642
  #3  0x00000000 in ?? ()

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