#!watchflakes
post <- goarch ~ `ppc64.*` && log ~ `panic during regalloc` && log ~ `^\s*cmd/compile/internal/ssa`
greplogs -l -e '(?ms)panic during regalloc .*cmd/compile/internal/ssa\.\(\*sparseSet\)\.add'
2022-05-13T21:33:25-4170084/linux-ppc64le-power9osu
(attn @randall77 @dr2chase @cherrymui; CC @golang/ppc64)
Comment From: bcmills
# encoding/json [encoding/json.test]
go/src/encoding/json/decode_test.go:2438:70: internal compiler error: 'TestUnmarshalRescanLiteralMangledUnquote': panic during regalloc while compiling TestUnmarshalRescanLiteralMangledUnquote:
runtime error: invalid memory address or nil pointer dereference
goroutine 46 [running]:
cmd/compile/internal/ssa.Compile.func1()
/workdir/go/src/cmd/compile/internal/ssa/compile.go:50 +0x7c
panic({0x85e800, 0xebf7c0})
/workdir/go/src/runtime/panic.go:882 +0x238
cmd/compile/internal/ssa.(*sparseSet).add(...)
/workdir/go/src/cmd/compile/internal/ssa/sparseset.go:39
cmd/compile/internal/ssa.(*sparseSet).addAll(...)
/workdir/go/src/cmd/compile/internal/ssa/sparseset.go:45
cmd/compile/internal/ssa.(*stackAllocState).computeLive(0xc0029394a0?, {0xc000f50c00?, 0x38?, 0x203030203030302?})
/workdir/go/src/cmd/compile/internal/ssa/stackalloc.go:367 +0xe38
cmd/compile/internal/ssa.(*stackAllocState).init(0xc0029394a0, 0xc0010101c0, {0xc000f50c00, 0x38, 0x38})
/workdir/go/src/cmd/compile/internal/ssa/stackalloc.go:126 +0x150
cmd/compile/internal/ssa.stackalloc(0xc0010101c0, {0xc000f50c00, 0x38, 0x38})
/workdir/go/src/cmd/compile/internal/ssa/stackalloc.go:88 +0x124
cmd/compile/internal/ssa.(*regAllocState).regalloc(0xc001154180, 0xc0010101c0)
/workdir/go/src/cmd/compile/internal/ssa/regalloc.go:1833 +0x1f8
cmd/compile/internal/ssa.regalloc(0xc0010101c0?)
/workdir/go/src/cmd/compile/internal/ssa/regalloc.go:148 +0x50
cmd/compile/internal/ssa.Compile(0xc0010101c0)
/workdir/go/src/cmd/compile/internal/ssa/compile.go:98 +0x928
cmd/compile/internal/ssagen.buildssa(0xc0012717c0, 0x0)
/workdir/go/src/cmd/compile/internal/ssagen/ssa.go:574 +0x1468
cmd/compile/internal/ssagen.Compile(0xc0012717c0, 0x0?)
/workdir/go/src/cmd/compile/internal/ssagen/pgen.go:183 +0x48
cmd/compile/internal/gc.compileFunctions.func4.1(0x0?)
/workdir/go/src/cmd/compile/internal/gc/compile.go:153 +0x4c
cmd/compile/internal/gc.compileFunctions.func3.1()
/workdir/go/src/cmd/compile/internal/gc/compile.go:140 +0x54
created by cmd/compile/internal/gc.compileFunctions.func3
/workdir/go/src/cmd/compile/internal/gc/compile.go:138 +0x8c
Comment From: bcmills
There have been several changes in stackalloc.go during the Go 1.19 cycle, so marking as release-blocker at least until we can determine whether this is a regression.
Comment From: dr2chase
It doesn't fail using the obvious cross-compilation:
GOOS=linux GOARCH=ppc64le go test -c encoding/json
which means, something wrong in that compiler? About to try it on a gomote....
Comment From: bcmills
It only failed once in the builder — looks like a nondeterministic failure.
My guesses would be either a race or (given the ssa package) a runtime bug involving a mishandled OOM condition.
Comment From: dr2chase
Oh joy. I've already verified that it doesn't reproduce (once) with
GOPPC64=power9 GOOS=linux GOARCH=ppc64le go test -c encoding/json
nor (once) on a plain ppc64le gomote.
Comment From: dr2chase
On the failing builder, with a normally built compiler
for i in {1..100} ; do go clean -cache ; go test -c encoding/json ; echo $i done ; done
over lunch worked fine.
Am about to retry with GOPPC64=power9 built compiler.
Comment From: ceseo
I can't reproduce it either (POWER9, with either GOPPC=power9 and GOPPC=power8.
Comment From: cherrymui
There have been several changes in stackalloc.go during the Go 1.19 cycle
I don't think we have recent changes in stackalloc.go. The most recent change I saw is https://go-review.googlesource.com/c/go/+/312292 , which is a year old.
I also built the compiler in race mode on PPC64LE and couldn't find a race or a crash in a reasonable amount of time.
Given the above, and it does not occur on a first class port, I think it is not a release blocker. Thanks.
Comment From: ianlancetaylor
As far as I can see this has happened exactly once.
Rolling forward to 1.20, but if it doesn't happen again we can close this.
Comment From: bcmills
greplogs -l -e '(?ms)panic during regalloc .*cmd/compile/internal/ssa' --since=2022-05-16
2022-08-31T21:10:41-52d9e7f/linux-ppc64-sid-buildlet
Comment From: bcmills
(That time was in (*sparseMap).set, but it seems like a close enough fit.)
Comment From: randall77
That last one looks like corruption to me. There's no way a negative number should appear in the slice involved (cmd/compile/internal/ssa.sparseMap.sparse). Entries start out 0 and every value assigned is known nonnegative.
Comment From: gopherbot
Found new dashboard test flakes for:
#!watchflakes
post <- log ~ `panic during regalloc` && log ~ `^\s*cmd/compile/internal/ssa`
2023-11-20 18:34 linux-ppc64-sid-buildlet tools@bd215c0c go@e1dc209b github.com/yuin/goldmark/util [build] (log)
../../../../pkg/mod/github.com/yuin/goldmark@v1.4.13/util/html5entities.go:18:53: internal compiler error: 'init': panic during regalloc while compiling init: runtime error: index out of range [134432465] with length 262144 goroutine 37 [running]: cmd/compile/internal/ssa.Compile.func1() /workdir/go/src/cmd/compile/internal/ssa/compile.go:49 +0x7c panic({0x939de0, 0xc003e42000}) /workdir/go/src/runtime/panic.go:884 +0x240 cmd/compile/internal/ssa.(*sparseMapPos).set(...) ... /workdir/go/src/cmd/compile/internal/gc/compile.go:171 +0x4c cmd/compile/internal/gc.compileFunctions.func3.1() /workdir/go/src/cmd/compile/internal/gc/compile.go:153 +0x44 created by cmd/compile/internal/gc.compileFunctions.func3 /workdir/go/src/cmd/compile/internal/gc/compile.go:152 +0x1f4 Please file a bug report including a short program that triggers the error. https://go.dev/issue/newComment From: mknyszek
CC @golang/ppc64
Comment From: pmur
I suspect the most recent flake here is another manifestation of #64290. The failed index is 0x80346d1, and if the high bit is cleared, the index is valid.