[Qemu-devel] [Bug 673613] Re: ARM semihosting SYS_GET_CMDLINE does not return arguments

[Aurelien Jarno]

** Changed in: qemu
       Status: Fix Committed => Fix Released

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https://bugs.launchpad.net/bugs/673613

Title:
  ARM semihosting SYS_GET_CMDLINE does not return arguments

Status in QEMU:
  Fix Released

Bug description:
  I have downloaded version 0.13.0 of the code, configured with:
  './configure' '--prefix=/tmp/qemu-0.13.0' '--interp-
  prefix=/tmp/qemu-0.13.0/usr/local/gnemul/qemu-%M' '--target-list=arm-
  softmmu arm-linux-user armeb-linux-user'

  and built using gcc version 4.3.2 (Debian 4.3.2-1.1). Execution
  environment is Debian, kernel 2.6.26-2-686.

  I am running a barebone helloworld.c which echoes its commandline
  arguments, compiled with ADS1.2 from ARM. The arguments never get
  echoed back.

  I have found the culprit in the source code, lines 3020 and 3022 of
  linux-user/main.c which free target_argv[]. However, loader_exec(),
  which is called a couple lines above, records the pointer to
  target_argv[]. So, when the data is accessed in arm-semi.c, it is
  actually trying to load from memory that has been free()d already.

  This bug manifests itself for baremetal simulation, but I suspect it
  hits other platforms as well.