Re: [Qemu-devel] [PATCH v3 2/2] avx2 configure: Use primitives in test

[Paolo Bonzini]

On 14/07/2016 15:13, Aaron Lindsay wrote:
> On Jun 10 12:16, Dr. David Alan Gilbert (git) wrote:
>> From: "Dr. David Alan Gilbert" <address@hidden>
>>
>> Use the avx2 primitives during the test, thus making sure that the
>> compiler and assembler could actually use avx2.
>>
>> This also detects the failure case on gcc 4.8.x with -save-temps
>> and avoids the need for the gcc version check in cutils.
> 
> I'm getting a segfault when running the latest tip compiled with gcc
> 4.8.4 on Ubuntu 14.04 and I've bisected it to this commit.
> 
> # gcc --version
> gcc (Ubuntu 4.8.4-2ubuntu1~14.04) 4.8.4
> 
> I'm configuring with:
> # ./configure \
>     --static \
>       --disable-gtk \
>       --target-list=aarch64-softmmu
> 
> When run under gdb, I get:
> Program received signal SIGSEGV, Segmentation fault.
> buffer_find_nonzero_offset_ifunc () at ./util/cutils.c:333
> 333     {
> (gdb) bt
> #0  buffer_find_nonzero_offset_ifunc () at ./util/cutils.c:333
> #1  0x0000000000939c58 in __libc_start_main ()
> #2  0x0000000000419337 in _start ()
> 
> I confess I don't understand the intricacies here, but I'm willing to
> test fixes if you have any ideas for how to make this also work for my
> compiler without blindly excluding all gcc < 4.9.

Hmm, it's possible that we have to disable ifunc together with --static.

Paolo