Re: [9fans] go floating point exception

[ron minnich <rminnich@gmail.com>]

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did you get a chance to check the value of mxcsr on 9legacy?

On Mon, Jan 5, 2026 at 4:48 AM <hahahahacker2009@gmail.com> wrote:

> > I can't reproduce it. I'm using a macOS host, with qemu 10.1.2, Go
> > 1.25.2 using rsc's 9legacy repo at
> > https://github.com/rsc/plan9
> > (it is convenient for qemu; u9fs serves the local content so you can
> > use host OS tools, etc.)
> >
>
> I copied the binary over rsc's tree but can't reproduce it there either.
> But it still happen on 9legacy installed from the iso.
> I cross compiled it on arm with go version go1.25.4 plan9/arm
>
> I formatted another fossil file system with the snapshot after I installed
> 9legacy from the iso, recompile kernel, etc (to make sure that there is
> no Geoff stuff). It still suicide with both http binaries (the one you've
> posted here and the one I sent earlier).
>
> (also, try running the fpnote test in rsc's /usr/glenda/src too,
> it still fails many times).
>
> > Does it fail on startup or 50% of the time when you send a request?
> > I use this modified Go http package example:
> >
> > package main
> >
> > import (
> >     "log"
> >     "net/http"
> > )
> >
> > func main() {
> >     log.Fatal(http.ListenAndServe(":9000",
> > http.FileServer(http.Dir("/sys/doc"))))
> > }
> >
> > On Fri, Jan 2, 2026 at 6:23 AM <hahahahacker2009@gmail.com> wrote:
> >>
> >> Hello,
> >> I don't know go, just have it to compile some programs.
> >> I cross-compiled this http server from arm for amd64:
> >> https://mkws.sh/https/https.go
> >>
> >> Running it on 9legacy/amd64 (under qemu) will raise this error 50% of
> >> the time (otherwise it works pretty well):
> >> gohttp 177: suicide: sys: fp: Precision Exception mxcsr=0x20 pc=0x215443
> >>
> >> Plan 9
> >> mmuinit: vmstart 0xfffffffff0000000 vmunused 0xfffffffff03cc000
> vmunmapped 0xfffffffff0400000 vmend 0xfffffffffe000000
> >> sys->pd 0x108003 0x108023
> >> l 3 0xffffff7fbfdfeff8 107023
> >> l 2 0xffffff7fbfdffff8 108023
> >> l 1 0xffffff7fbffffc00 e3
> >> l 1 0xffffff7fbffffc00 e3
> >> base 0xfffffffff03d0000 ptr 0xfffffffff03d0000 nunits 14430208
> >> physalloc color=0 base=0xe000000 size=0x71fe0000
> >> apic0: hz 998949300 max 9989493 min 99894 div 3
> >> intrenable: nil handler for 11, tbdf 0xc001800 for ether0
> >> #l0: virtio10: 1Gbps port 0xfe000000 irq 11: 525400123456
> >> 2044M memory: 2800K+220M kernel, 1822M user, 0M lost
> >> pickmethod...read #e/nobootprompt...pickmethod done
> >> bind #æ...bind #S...partinit...part plan9 63 67103505
> >> p9part /dev/sdC0/data plan9
> >> part 9fat 63 204863
> >> part nvram 204863 204864
> >> part fossil 204864 10573102
> >> part arenas 10573102 62414293
> >> part isect 62414293 65006353
> >> part bloom 65006353 65530641
> >> auth...mount usbd...can't open /srv/usbtime...
> >> venti...2026/0102 11:36:29 venti: conf.../boot/venti: mem 2,236,962
> bcmem 4,473,924 icmem 6,710,886...httpd tcp!127.1!8000...init...icache
> 6,710,886 bytes = 66,728 entries; 4 scache
> >> sync...announce tcp!127.1!17034...serving.
> >> fossil(#S/sdC0/fossil)...fsys: dialing venti at tcp!127.1!17034
> >> version...can't stat /srv/partfs.sdXX: '/srv/partfs.sdXX' file does not
> exist
> >>
> >> init: starting /bin/rc
> >> secstore
> >> mkvbe: '/dev/realmode' file does not exist
> >> aux/vga: controller not in /lib/vgadb, not vesa
> >> 0xC0000 55 AA 4D E9 90 55 CC 00 00 00 00 00 00 00 00 00
> U.M..U..........
> >> 0xC0010 00 00 00 00 00 00 00 00 5C 98 00 00 00 00 49 42
> ........\.....IB
> >> 0xC0020 4D 00 2E 8B 16 E8 98 85 D2 74 01 EE C2 02 00 84
> M........t......
> >> 0xC0030 C0 74 34 66 55 66 89 E5 66 53 66 89 C3 66 B8 00
> .t4fUf..fSf..f..
> >> 0xC0040 40 00 00 FE CB 74 37 66 0F B7 D2 66 0F B7 C9 66
> @....t7f...f...f
> >> 0xC0050 0F AF D1 66 C1 FA 03 66 89 D0 9C 66 05 FF 1F 00
> ...f...f...f....
> >> 0xC0060 00 9D 25 00 E0 EB 17 0F AF CA 66 89 C8 9C 66 D1
> ..%.......f...f.
> >> 0xC0070 E0 66 05 FF 07 00 00 9D 25 00 F8 C2 02 00 66 5B
> .f......%.....f[
> >> 0xC0080 66 5D C2 02 00 66 55 66 89 E5 66 56 66 53 66 89
> f]...fUf..fVfSf.
> >> 0xC0090 C6 66 89 D3 66 89 CA 67 66 8B 4D 08 67 8A 45 0C
> .f..f..gf.M.g.E.
> >> 0xC00A0 66 C1 E6 10 66 0F B7 DB 66 09 F3 66 31 F6 8E C6
> f...f...f..f1...
> >> 0xC00B0 26 66 89 1E 0C 01 80 F9 01 74 0D 80 F9 03 74 0C
> &f.......t....t.
> >> 0xC00C0 84 C9 74 0A B0 19 EB 06 B0 0E EB 02 B0 2B 66 B9
> ..t..........+f.
> >> 0xC00D0 40 00 00 00 8E C1 66 48 26 A2 84 00 8E C1 66 0F
> @.....fH&.....f.
> >> 0xC00E0 B6 D2 26 89 16 85 00 66 5B 66 5E 66 5D C2 02 00
> ..&....f[f^f]...
> >> 0xC00F0 66 55 66 89 E5 66 57 66 56 66 53 66 53 66 89 C3
> fUf..fWfVfSfSf..
> >> aux/vga: main: vga@1024x768x1 not in /lib/vgadb
> >> rio: can't open display: initdisplay: /dev/draw/new: no frame buffer
> >> init: rc exit status: rio 41: display open
> >>
> >> init: starting /bin/rc
> >> term%
> >>

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