Re: [Qemu-devel] ARM brk bug

["Bernhard M. Wiedemann" <bwiedemann@suse.de>]

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On 02/27/2012 04:32 PM, Peter Maydell wrote:
> On 27 February 2012 15:16, Bernhard M. Wiedemann
> <bwiedemann@suse.de> wrote:
>> I found that running a debian arm5 bash with qemu runs into
>> varying problems with -R but works without. Also works fine on
>> both armv5 and armv7hf hardware.
>> 
>> 
>> This happened with both master and 1.0 builds:
>> 
>> curl www.zq1.de/~bernhard/temp/debian-bash-bug-nss-minimal.tar.gz
>> |\ tar xz cd debian-bash-bug-nss-minimal 
>> path/to/qemu/arm-linux-user/qemu-arm -R 500M -L . bin/bash qemu:
>> uncaught target signal 11 (Segmentation fault) - core dumped 
>> Segmentation fault
> 
>> but otherwise it failed with messages like bash: xmalloc:
>> ../bash/variables.c:1971: cannot allocate 2 bytes (8192 bytes
>> allocated)
> 
> So, er, don't do that then? This looks suspiciously like we're 
> failing an mmap() (because of the limited guest address space
> you've asked for with -R) and then bash is either failing to handle
> it and crashing or printing a message about the allocation
> failure.
> 
> -- PMM

apparently, we patched qemu for openSUSE to always use -R because
otherwise java did not work (with the binfmt chroot magic).

even when I used the highest possible value for -R it did not work:

qemu-arm -R 4026M -L . bin/bash
bash: xmalloc: ../bash/variables.c:1971: cannot allocate 2 bytes (8192
bytes allocated)

even though it worked with any other arm binary I tried (including
openSUSE's bash, Debians dash etc).


Ciao
Bernhard M.
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