Re: [PULL 81/94] target/sparc: Move FDMULQ to decodetree

[Richard Henderson]

On 11/6/23 14:02, Mark Cave-Ayland wrote:
> I was working through my SPARC boot tests for your latest target/sparc series when I 
> spotted a segfault on my FreeBSD SPARC64 image. A git bisect indicated that this was the 
> patch that originally introduced the error, something I must have missed when testing the 
> original decodetree conversion series.
>
> The reproducer is:
>
> ./qemu-system-sparc64 -m 256 -cdrom FreeBSD-10.3-RELEASE-sparc64-bootonly.iso \
>      -boot d -nographic
>
> and the error is a segfault in devd:
>
> ...
> ...
> Trying to mount root from cd9660:/dev/iso9660/10_3_RELEASE_SPARC64_BO [ro]...
> Entropy harvesting: interrupts ethernet point_to_point swi.
> Starting file system checks:
> Mounting local file systems:.
> Writing entropy file:.
> /etc/rc: WARNING: $hostname is not set -- see rc.conf(5).
> Starting Network: lo0 hme0.
> lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384
>          options=600003<RXCSUM,TXCSUM,RXCSUM_IPV6,TXCSUM_IPV6>
>          inet6 ::1 prefixlen 128
>          inet6 fe80::1%lo0 prefixlen 64 scopeid 0x2
>          inet 127.0.0.1 netmask 0xff000000
>          nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
> hme0: flags=8802<BROADCAST,SIMPLEX,MULTICAST> metric 0 mtu 1500
>          options=8000b<RXCSUM,TXCSUM,VLAN_MTU,LINKSTATE>
>          ether 52:54:00:12:34:56
>          nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
>          media: Ethernet autoselect
> Starting devd.
> pid 246 (ps), uid 0: exited on signal 11
> Segmentation fault
> ^^^^^^^^^^^^^^^^^^


I certainly can't imagine that FdMULq is really at fault, because it's not implemented on 
real hardware (and thus I really doubt FreeBSD attempted to use it), and 
CPU_FEATURE_FLOAT128 is not enabled by your command-line.

The only thing that I can imagine is that this is some sort of timing related issue and 
bisect behaved randomly.

All that said, I can't replicate this with master.
Can you, now?


r~