[Bug 1920602] Re: QEMU crash after a QuickBASIC program integer overflow

[Aaro Koskinen]

Attached is a minimal FreeDOS floppy disk to reproduce the TCG crash.
Still reproducible with QEMU v6.0.0:

WARNING: Image format was not specified for 'test-floppy.img' and probing 
guessed raw.
         Automatically detecting the format is dangerous for raw images, write 
operations on block 0 will be restricted.
         Specify the 'raw' format explicitly to remove the restrictions.
SeaBIOS (version rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org)
Booting from Floppy...
................................................123
FreeDOS kernel 2042 (build 2042 OEM:0xfd) [compiled May 11 2016]
Kernel compatibility 7.10 - WATCOMC - FAT32 support

(C) Copyright 1995-2012 Pasquale J. Villani and The FreeDOS Project.
All Rights Reserved. This is free software and comes with ABSOLUTELY NO
WARRANTY; you can redistribute it and/or modify it under the terms of the
GNU General Public License as published by the Free Software Foundation;
either version 2, or (at your option) any later version.
 - InitDiskno hard disks detected

FreeCom version 0.84-pre2 XMS_Swap [Aug 28 2006 00:29:00]
A:\>KILLER.EXE
**
ERROR:../accel/tcg/tcg-accel-ops.c:80:tcg_handle_interrupt: assertion failed: 
(qemu_mutex_iothread_locked())
Bail out! ERROR:../accel/tcg/tcg-accel-ops.c:80:tcg_handle_interrupt: assertion 
failed: (qemu_mutex_iothread_locked())
Aborted


** Attachment added: "test-floppy.img.gz"
   
https://bugs.launchpad.net/qemu/+bug/1920602/+attachment/5495920/+files/test-floppy.img.gz

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https://bugs.launchpad.net/bugs/1920602

Title:
  QEMU crash after a QuickBASIC program integer overflow

Status in QEMU:
  New

Bug description:
  A trivial program compiled with QuickBASIC 4.5 with integer overflow
  will crash QEMU when ran under MS-DOS 5.0 or FreeDOS 1.2:

  C:\KILLER>type killer.bas
  A% = VAL("99999"):PRINT A%

  C:\KILLER>killer.exe
  **
    ERROR:../qemu-5.2.0/accel/tcg/tcg-cpus.c:541:tcg_handle_interrupt: 
assertion failed: (qemu_mutex_iothread_locked())
  Aborted

  QEMU version v5.2, compiler for ARM, and started with command line:

  qemu-system-i386 -curses -cpu 486 -m 1 -drive dos.img

  The same test under Ubuntu QEMU and KVM/x86_64 (QEMU emulator version
  4.2.1 (Debian 1:4.2-3ubuntu6.14)) will just silently hang the QEMU. On
  DOSBOX, the machine does not die and program outputs the value -31073.

  The EXE to reproduce the issue is attached.

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