qemu ExcludeArch %{arm} (was: Re: GCC crash on Fedora Rawhide armv7)

[Richard W.M. Jones]

[Adding qemu maintainers]

On Mon, Nov 22, 2021 at 05:55:06PM +0000, Richard W.M. Jones wrote:
>  
>    gcc -Ilibqemuutil.a.p -I. -I.. -Isubprojects/libvhost-user
> -I../subprojects/libvhost-user -Iqapi -Itrace -Iui -Iui/shader -I/usr/include/glib-2.0
> -I/usr/lib/glib-2.0/include -I/usr/include/sysprof-4 -I/usr/include/libmount
> -I/usr/include/blkid -I/usr/include/gio-unix-2.0 -I/usr/include/p11-kit-1
> -I/usr/include/pixman-1 -fdiagnostics-color=auto -Wall -Winvalid-pch -std=gnu11 -O2 -g
> -isystem /builddir/build/BUILD/qemu-6.1.0/linux-headers -isystem linux-headers -iquote .
> -iquote /builddir/build/BUILD/qemu-6.1.0 -iquote /builddir/build/BUILD/qemu-6.1.0/include
> -iquote /builddir/build/BUILD/qemu-6.1.0/disas/libvixl -iquote
> /builddir/build/BUILD/qemu-6.1.0/tcg/arm -pthread -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2
> -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -Wstrict-prototypes
> -Wredundant-decls -Wundef -Wwrite-strings -Wmissing-prototypes -fno-strict-aliasing
> -fno-common -fwrapv -O2 -fexceptions -g -grecord-gcc-switches -pipe -Wall
> -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS
> -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -march=armv7-a
> -mfpu=vfpv3-d16 -mtune=generic-armv7-a -mabi=aapcs-linux -mfloat-abi=hard
> -Wold-style-declaration -Wold-style-definition -Wtype-limits -Wformat-security
> -Wformat-y2k -Winit-self -Wignored-qualifiers -Wempty-body -Wnested-externs -Wendif-labels
> -Wexpansion-to-defined -Wimplicit-fallthrough=2 -Wno-missing-include-dirs
> -Wno-shift-negative-value -Wno-psabi -fstack-protector-strong -DSTAP_SDT_V2 -fPIE -MD -MQ
> libqemuutil.a.p/util_vfio-helpers.c.o -MF libqemuutil.a.p/util_vfio-helpers.c.o.d -o
> libqemuutil.a.p/util_vfio-helpers.c.o -c ../util/vfio-helpers.c
>    during RTL pass: mach
>    ../util/vfio-helpers.c: In function 'qemu_vfio_open_pci':
>    ../util/vfio-helpers.c:523:1: internal compiler error: in create_fix_barrier, at
> config/arm/arm.c:17891
>      523 | }
>          | ^
>    Please submit a full bug report,
>    with preprocessed source if appropriate.
>    See <http://bugzilla.redhat.com/bugzilla> for instructions.
>    Preprocessed source stored into /tmp/ccOFlWwZ.out file, please attach this to your
> bugreport.
>  
>  Unfortunately the crash happened in Koji:
>  https://koji.fedoraproject.org/koji/taskinfo?taskID=79160330
>  
>  I'm not able to reproduce it locally, which is strange.  I've got an
>  armv7 guest which has the same version of gcc, binutils and annobin,
>  yet it does not crash compiling the same file.
>  
>  I wonder if anyone can manage to reproduce this and capture the
>  /tmp/*.out file?  In theory all you need to do is build qemu from
>  dist-git on armv7.
>  
>  Alternatively, can anyone think of a reason why this crash would
>  happen in Koji but not in an armv7 guest (on aarch64 host)? 
I'm still unable to reproduce this bug locally.

But as a result, qemu is currently ExcludeArch %{arm}.  This means
that various other packages will start to be affected (I had to add
the same to virt-v2v in Fedora just now).

I don't know how to proceed here - it seems like it's a GCC bug, so
simply reverting the ExcludeArch commit will NOT help us.

I would favour permanently excluding armv7, as it is unlikely anyone
is really running VMs on 32 bit ARM, but obviously that will have
knock-on effects through the rest of the stack.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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