[Qemu-devel] [Bug 1192344] [NEW] qemu crashes on unaligned extended disk reads

[Qemu-devel] [Bug 1192344] [NEW] qemu crashes on unaligned extended disk reads

[Andrew McGowen]

Public bug reported:

When performing a BIOS extended disk read (INT 13H, AH=0x42), if the
offset of the buffer destination in the DAP (disk address packet) is not
dword-aligned (i.e. a multiple of 4), SeaBIOS attempts to execute code
at non-mapped address 0xb4f53, causing QEMU to crash. I imagine it's a
bug in the BIOS code, but it does cause QEMU to crash.

QEMU version: 1.4.0 (Debian 1.4.0+dfsg-1expubuntu4) (from Ubuntu repository)
SeaBIOS version: 1.7.2-20130119_170942-roseapple
command line: qemu-system-x86_64 -m 64 -hda hda.img -monitor stdio
CPU: Intel Core i7 CPU M620 on a Dell Latitude E6410
OS: Ubuntu, GNU/Linux 3.8.0-25-generic, 64-bit

** Affects: qemu
     Importance: Undecided
         Status: New

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1192344

Title:
  qemu crashes on unaligned extended disk reads

Status in QEMU:
  New

Bug description:
  When performing a BIOS extended disk read (INT 13H, AH=0x42), if the
  offset of the buffer destination in the DAP (disk address packet) is
  not dword-aligned (i.e. a multiple of 4), SeaBIOS attempts to execute
  code at non-mapped address 0xb4f53, causing QEMU to crash. I imagine
  it's a bug in the BIOS code, but it does cause QEMU to crash.

  QEMU version: 1.4.0 (Debian 1.4.0+dfsg-1expubuntu4) (from Ubuntu repository)
  SeaBIOS version: 1.7.2-20130119_170942-roseapple
  command line: qemu-system-x86_64 -m 64 -hda hda.img -monitor stdio
  CPU: Intel Core i7 CPU M620 on a Dell Latitude E6410
  OS: Ubuntu, GNU/Linux 3.8.0-25-generic, 64-bit

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1192344/+subscriptions

Re: [Qemu-devel] [Bug 1192344] [NEW] qemu crashes on unaligned extended disk reads

[Stefan Hajnoczi]

On Tue, Jun 18, 2013 at 09:23:31PM -0000, Andrew McGowen wrote:
> When performing a BIOS extended disk read (INT 13H, AH=0x42), if the
> offset of the buffer destination in the DAP (disk address packet) is not
> dword-aligned (i.e. a multiple of 4), SeaBIOS attempts to execute code
> at non-mapped address 0xb4f53, causing QEMU to crash. I imagine it's a
> bug in the BIOS code, but it does cause QEMU to crash.

Can you post details on the "crash"?  What is the error message?

Stefan

[Qemu-devel] [Bug 1192344] Re: qemu crashes on unaligned extended disk reads

[Andrew McGowen]

...well this is embarrassing - it was an issue with my code not
saving/restoring registers on the stack properly.

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1192344

Title:
  qemu crashes on unaligned extended disk reads

Status in QEMU:
  New

Bug description:
  When performing a BIOS extended disk read (INT 13H, AH=0x42), if the
  offset of the buffer destination in the DAP (disk address packet) is
  not dword-aligned (i.e. a multiple of 4), SeaBIOS attempts to execute
  code at non-mapped address 0xb4f53, causing QEMU to crash. I imagine
  it's a bug in the BIOS code, but it does cause QEMU to crash.

  QEMU version: 1.4.0 (Debian 1.4.0+dfsg-1expubuntu4) (from Ubuntu repository)
  SeaBIOS version: 1.7.2-20130119_170942-roseapple
  command line: qemu-system-x86_64 -m 64 -hda hda.img -monitor stdio
  CPU: Intel Core i7 CPU M620 on a Dell Latitude E6410
  OS: Ubuntu, GNU/Linux 3.8.0-25-generic, 64-bit

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1192344/+subscriptions

[Qemu-devel] [Bug 1192344] Re: qemu crashes on unaligned extended disk reads

[T. Huth]

Marking this ticket as "Invalid" according to comment #2.

** Changed in: qemu
       Status: New => Invalid

-- 
You received this bug notification because you are a member of qemu-
devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1192344

Title:
  qemu crashes on unaligned extended disk reads

Status in QEMU:
  Invalid

Bug description:
  When performing a BIOS extended disk read (INT 13H, AH=0x42), if the
  offset of the buffer destination in the DAP (disk address packet) is
  not dword-aligned (i.e. a multiple of 4), SeaBIOS attempts to execute
  code at non-mapped address 0xb4f53, causing QEMU to crash. I imagine
  it's a bug in the BIOS code, but it does cause QEMU to crash.

  QEMU version: 1.4.0 (Debian 1.4.0+dfsg-1expubuntu4) (from Ubuntu repository)
  SeaBIOS version: 1.7.2-20130119_170942-roseapple
  command line: qemu-system-x86_64 -m 64 -hda hda.img -monitor stdio
  CPU: Intel Core i7 CPU M620 on a Dell Latitude E6410
  OS: Ubuntu, GNU/Linux 3.8.0-25-generic, 64-bit

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1192344/+subscriptions