cmd/go: go1.11.4 toolchain3 build fail with "slice bounds out of range" on 32-bit MIPS on Debian buildd #29402

anthonyfok · 2018-12-23T15:45:33Z

go1.11.4 fails to build toolchain3 with a "panic: runtime error: slice bounds out of range" on 32-bit MIPS architectures (mips, mipsel (or mipsle)) on Debian buildd. This seems to be a new problem because go1.11.2 and go1.11.3 built fine.

Here is where it failed:

Building Go cmd/dist using /usr/lib/go-1.10.
go: disabling cache (/sbuild-nonexistent/.cache/go-build) due to initialization failure: mkdir /sbuild-nonexistent: permission denied
Building Go toolchain1 using /usr/lib/go-1.10.
Building Go bootstrap cmd/go (go_bootstrap) using Go toolchain1.
Building Go toolchain2 using go_bootstrap and Go toolchain1.
Building Go toolchain3 using go_bootstrap and Go toolchain2.
# unicode
panic: runtime error: slice bounds out of range

goroutine 1 [running]:
cmd/compile/internal/gc.(*exprSwitch).walkCases(0x1bf39a0, 0x201aec0, 0x4, 0x4, 0x201aec0)
	/usr/lib/go-1.11/src/cmd/compile/internal/gc/swt.go:396 +0x918
cmd/compile/internal/gc.(*exprSwitch).walk(0x1bf39a0, 0x16c0b40)
	/usr/lib/go-1.11/src/cmd/compile/internal/gc/swt.go:325 +0x380
cmd/compile/internal/gc.walkswitch(0x16c0b40)
	/usr/lib/go-1.11/src/cmd/compile/internal/gc/swt.go:234 +0xa8
cmd/compile/internal/gc.walkstmt(0x16c0b40, 0x8)
	/usr/lib/go-1.11/src/cmd/compile/internal/gc/walk.go:346 +0xd64
cmd/compile/internal/gc.walkstmtlist(0x165bbd8, 0x2, 0x2)
	/usr/lib/go-1.11/src/cmd/compile/internal/gc/walk.go:79 +0x90
cmd/compile/internal/gc.walkstmt(0x16c09b0, 0x4)
	/usr/lib/go-1.11/src/cmd/compile/internal/gc/walk.go:286 +0x1208
cmd/compile/internal/gc.walkstmtlist(0x1ae95d0, 0x4, 0x4)
	/usr/lib/go-1.11/src/cmd/compile/internal/gc/walk.go:79 +0x90
cmd/compile/internal/gc.walk(0x16b46c0)
	/usr/lib/go-1.11/src/cmd/compile/internal/gc/walk.go:63 +0x22c
cmd/compile/internal/gc.compile(0x16b46c0)
	/usr/lib/go-1.11/src/cmd/compile/internal/gc/pgen.go:223 +0x80
cmd/compile/internal/gc.funccompile(0x16b46c0)
	/usr/lib/go-1.11/src/cmd/compile/internal/gc/pgen.go:209 +0xf4
cmd/compile/internal/gc.Main(0x96654c)
	/usr/lib/go-1.11/src/cmd/compile/internal/gc/main.go:641 +0x290c
main.main()
	/usr/lib/go-1.11/src/cmd/compile/main.go:51 +0xac
# math
panic: runtime error: slice bounds out of range
...
# runtime
panic: runtime error: slice bounds out of range
...

See full build logs here:

Sorry, I haven't had the time to try to study this in depth by logging into Debian's remote 32-bit MIPS machine yet, but thought I should try my luck here first. :-) Many thanks!

The text was updated successfully, but these errors were encountered:

randall77 · 2018-12-23T17:12:03Z

Weird. The code does:

var a []T = ...
half := len(a)/2
_, _ = a[:half], a[half:]

Which should not be able to panic.
Could be a bug in the compiler, though.

I can't seem to gomote a linux-mips or linux-mipsle machine. Someone with access to such a machine care to verify and do a bisect?

anthonyfok · 2018-12-25T16:36:44Z

Hi Randall,

Thank you for the suggestion!

I have finally sat down and got a "schroot" environment set up on the Debian mipsel and mips development machines and got a "git bisect run" going on both machines:

git bisect start go1.11.4 go1.11.3
git bisect run ../build-go.sh

where ../build-go.sh has this:

#!/bin/sh
cd src
./make.bash

I will go back check the result in a few hours. :-)

Have a Happy Christmas! 🎄

anthonyfok · 2018-12-25T22:30:10Z

Here is the result of git bisect test, identical on both mips and mipsel:

...

Bisecting: 0 revisions left to test after this (roughly 0 steps)
[bdc7d5677edd1dab21cdaa1f6498e0c2a6c9d7bf] [release-branch.go1.11] cmd/compile: 
check for negative upper bound to IsSliceInBounds
running ../build-go.sh
Building Go cmd/dist using /usr/lib/go-1.10.
Building Go toolchain1 using /usr/lib/go-1.10.
Building Go bootstrap cmd/go (go_bootstrap) using Go toolchain1.
Building Go toolchain2 using go_bootstrap and Go toolchain1.
Building Go toolchain3 using go_bootstrap and Go toolchain2.
# unicode
panic: runtime error: slice bounds out of range

goroutine 1 [running]:
cmd/compile/internal/gc.(*exprSwitch).walkCases(0x1bb99a0, 0x1fe4ec0, 0x4, 0x4, 0x1fe4ec0)
        /home/foka/git/go/src/cmd/compile/internal/gc/swt.go:396 +0x918
cmd/compile/internal/gc.(*exprSwitch).walk(0x1bb99a0, 0x1694370)
        /home/foka/git/go/src/cmd/compile/internal/gc/swt.go:325 +0x380
cmd/compile/internal/gc.walkswitch(0x1694370)
        /home/foka/git/go/src/cmd/compile/internal/gc/swt.go:234 +0xa8
cmd/compile/internal/gc.walkstmt(0x1694370, 0x8)
        /home/foka/git/go/src/cmd/compile/internal/gc/walk.go:346 +0xd64
cmd/compile/internal/gc.walkstmtlist(0x185f6c8, 0x2, 0x2)
        /home/foka/git/go/src/cmd/compile/internal/gc/walk.go:79 +0x90
cmd/compile/internal/gc.walkstmt(0x16941e0, 0x4)
        /home/foka/git/go/src/cmd/compile/internal/gc/walk.go:286 +0x1208
cmd/compile/internal/gc.walkstmtlist(0x1bbb5c0, 0x4, 0x4)
        /home/foka/git/go/src/cmd/compile/internal/gc/walk.go:79 +0x90
cmd/compile/internal/gc.walk(0x165a780)
        /home/foka/git/go/src/cmd/compile/internal/gc/walk.go:63 +0x22c
cmd/compile/internal/gc.compile(0x165a780)
        /home/foka/git/go/src/cmd/compile/internal/gc/pgen.go:223 +0x80
cmd/compile/internal/gc.funccompile(0x165a780)
        /home/foka/git/go/src/cmd/compile/internal/gc/pgen.go:209 +0xf4
cmd/compile/internal/gc.Main(0x96656c)
        /home/foka/git/go/src/cmd/compile/internal/gc/main.go:641 +0x2910
main.main()
        /home/foka/git/go/src/cmd/compile/main.go:51 +0xac
# math  
panic: runtime error: slice bounds out of range

goroutine 1 [running]:
cmd/compile/internal/gc.(*exprSwitch).walkCases(0x1e798b4, 0x1da1a80, 0x4, 0x4, 0x1da1a80)
        /home/foka/git/go/src/cmd/compile/internal/gc/swt.go:396 +0x918
cmd/compile/internal/gc.(*exprSwitch).walk(0x1e798b4, 0x1c6c8c0)
        /home/foka/git/go/src/cmd/compile/internal/gc/swt.go:325 +0x380
cmd/compile/internal/gc.walkswitch(0x1c6c8c0)
        /home/foka/git/go/src/cmd/compile/internal/gc/swt.go:234 +0xa8
cmd/compile/internal/gc.walkstmt(0x1c6c8c0, 0x1c6c820)
        /home/foka/git/go/src/cmd/compile/internal/gc/walk.go:346 +0xd64
cmd/compile/internal/gc.walkstmtlist(0x1bfe7c0, 0x6, 0x8)
        /home/foka/git/go/src/cmd/compile/internal/gc/walk.go:79 +0x90
cmd/compile/internal/gc.walkstmt(0x1c6c6e0, 0x1c6c230)
        /home/foka/git/go/src/cmd/compile/internal/gc/walk.go:286 +0x1208
cmd/compile/internal/gc.walkstmtlist(0x1c769f8, 0x1, 0x2)
        /home/foka/git/go/src/cmd/compile/internal/gc/walk.go:79 +0x90
cmd/compile/internal/gc.walkstmt(0x1c6c5a0, 0x1c6c500)
        /home/foka/git/go/src/cmd/compile/internal/gc/walk.go:286 +0x1208
cmd/compile/internal/gc.walkstmtlist(0x1da1540, 0xf, 0x10)
        /home/foka/git/go/src/cmd/compile/internal/gc/walk.go:79 +0x90
cmd/compile/internal/gc.walk(0x1c16900)
        /home/foka/git/go/src/cmd/compile/internal/gc/walk.go:63 +0x22c
cmd/compile/internal/gc.compile(0x1c16900) 
        /home/foka/git/go/src/cmd/compile/internal/gc/pgen.go:223 +0x80
cmd/compile/internal/gc.funccompile(0x1c16900)
        /home/foka/git/go/src/cmd/compile/internal/gc/pgen.go:209 +0xf4
cmd/compile/internal/gc.Main(0x96656c)
        /home/foka/git/go/src/cmd/compile/internal/gc/main.go:641 +0x2910
main.main()
        /home/foka/git/go/src/cmd/compile/main.go:51 +0xac
# runtime
panic: runtime error: slice bounds out of range

goroutine 1 [running]:
cmd/compile/internal/gc.(*exprSwitch).walkCases(0x30b9a8c, 0x20ba300, 0xb, 0x10, 0x20ba300)
        /home/foka/git/go/src/cmd/compile/internal/gc/swt.go:396 +0x918
cmd/compile/internal/gc.(*exprSwitch).walk(0x30b9a8c, 0x1c12190)
        /home/foka/git/go/src/cmd/compile/internal/gc/swt.go:325 +0x380
cmd/compile/internal/gc.walkswitch(0x1c12190)
        /home/foka/git/go/src/cmd/compile/internal/gc/swt.go:234 +0xa8
cmd/compile/internal/gc.walkstmt(0x1c12190, 0x1c0bf90)
        /home/foka/git/go/src/cmd/compile/internal/gc/walk.go:346 +0xd64
cmd/compile/internal/gc.walkstmtlist(0x293b180, 0x13, 0x20)
        /home/foka/git/go/src/cmd/compile/internal/gc/walk.go:79 +0x90
cmd/compile/internal/gc.walk(0x1c02180)
        /home/foka/git/go/src/cmd/compile/internal/gc/walk.go:63 +0x22c
cmd/compile/internal/gc.compile(0x1c02180) 
        /home/foka/git/go/src/cmd/compile/internal/gc/pgen.go:223 +0x80
cmd/compile/internal/gc.funccompile(0x1c02180)
        /home/foka/git/go/src/cmd/compile/internal/gc/pgen.go:209 +0xf4
cmd/compile/internal/gc.Main(0x96656c)
        /home/foka/git/go/src/cmd/compile/internal/gc/main.go:641 +0x2910
main.main()
        /home/foka/git/go/src/cmd/compile/main.go:51 +0xac
go tool dist: FAILED: /home/foka/git/go/pkg/tool/linux_mipsle/go_bootstrap install -gcflags=all= -ldflags=all= -a -i cmd/asm cmd/cgo cmd/compile cmd/link: exit status 2
bdc7d5677edd1dab21cdaa1f6498e0c2a6c9d7bf is the first bad commit
commit bdc7d5677edd1dab21cdaa1f6498e0c2a6c9d7bf
Date:   Tue Dec 4 10:00:16 2018 -0500

    [release-branch.go1.11] cmd/compile: check for negative upper bound to IsSliceInBounds

    IsSliceInBounds(x, y) asserts that y is not negative, but
    there were cases where this is not true.  Change code
    generation to ensure that this is true when it's not obviously
    true.  Prove phase cleans a few of these out.

    With this change the compiler text section is 0.06% larger,
    that is, not very much.  Benchmarking still TBD, may need
    to wait for access to a benchmarking box (next week).

    Also corrected run.go to handle '?' in -update_errors output.

    Fixes #28799.

    Change-Id: Ia8af90bc50a91ae6e934ef973def8d3f398fac7b
    Reviewed-on: https://go-review.googlesource.com/c/152477
    Run-TryBot: David Chase <[email protected]>
    Reviewed-by: Keith Randall <[email protected]>
    TryBot-Result: Gobot Gobot <[email protected]>
    (cherry picked from commit ea6259d5e9d57f247b7d877d4d04602b74ae5155)
    Reviewed-on: https://go-review.googlesource.com/c/153638

:040000 040000 34b03646370c2be9c266fbe248d7424aa466858f ed5ece622de7c63dc9181de93e12126917823c0b M      src
:040000 040000 e2d13d5ad7fa89cdf17e9e209e72b2320bd876c9 5172879f5db0b147c31ae3cfa535f75aba301c87 M      test
bisect run success

Bisect log:

(sid_mipsel-dchroot)foka@eller:~/git/go$ git bisect log
# bad: [4601a4c1b1c00fbe507508f0267ec5a9445bb7e5] [release-branch.go1.11] go1.11.4
# good: [90c896448691b5edb0ab11110f37234f63cd28ed] [release-branch.go1.11-security] go1.11.3
git bisect start 'go1.11.4' 'go1.11.3'
# good: [71b7b4fad3ac6d9ee543b27a9516a9d63ccd9596] [release-branch.go1.11] cmd/link: close input files when copying to temporary directory
git bisect good 71b7b4fad3ac6d9ee543b27a9516a9d63ccd9596
# bad: [928a4b69195f1f408e4cdb6ad4ee41f5f91f4e86] [release-branch.go1.11] cmd/cgo: preserve type information across loadDWARF loop
git bisect bad 928a4b69195f1f408e4cdb6ad4ee41f5f91f4e86
# good: [b86522faa54413930d6e9164973166490babc5de] [release-branch.go1.11] cmd/go/internal/modfetch: skip symlinks in (*coderepo).Zip
git bisect good b86522faa54413930d6e9164973166490babc5de
# bad: [a1d388ebf217d5582c24057cec4ccd053239dfc9] [release-branch.go1.11] doc/go1.11: add note about go run supporting for go run pkg or go run .
git bisect bad a1d388ebf217d5582c24057cec4ccd053239dfc9
# bad: [bdc7d5677edd1dab21cdaa1f6498e0c2a6c9d7bf] [release-branch.go1.11] cmd/compile: check for negative upper bound to IsSliceInBounds
git bisect bad bdc7d5677edd1dab21cdaa1f6498e0c2a6c9d7bf
# first bad commit: [bdc7d5677edd1dab21cdaa1f6498e0c2a6c9d7bf] [release-branch.go1.11] cmd/compile: check for negative upper bound to IsSliceInBounds

See:

commit bdc7d56
https://go-review.googlesource.com/c/go/+/153638
runtime: fatal error: out of memory on reslice with negative index [1.11 backport] runtime: fatal error: out of memory on reslice with negative index [1.11 backport] #28799
cmd/compile: fatal error: out of memory on reslice with negative index cmd/compile: fatal error: out of memory on reslice with negative index #28797

randall77 · 2018-12-25T22:55:35Z

@dr2chase

randall77 · 2018-12-25T22:55:42Z

Thanks for the bisect.

cherrymui · 2018-12-26T00:35:32Z

I don't have a MIPS machine on hand, but by visual inspection I think this is mis-compiled. Simple reproducer:

func F(s []int) bool {
	half := len(s)/2
	return half >= 0
}

On tip, I got

"".F STEXT size=12 args=0x10 locals=0x0 leaf
	0x0000 00000 (x.go:3)	TEXT	"".F(SB), LEAF|NOFRAME|ABIInternal, $-4-16
	0x0000 00000 (x.go:3)	FUNCDATA	$0, gclocals·4af967f5c52a6bcdb18ad5576e446d49(SB)
	0x0000 00000 (x.go:3)	FUNCDATA	$1, gclocals·2002e13acf59079a1a5782c918894579(SB)
	0x0000 00000 (x.go:3)	FUNCDATA	$3, gclocals·2002e13acf59079a1a5782c918894579(SB)
	0x0000 00000 (x.go:5)	PCDATA	$2, $0
	0x0000 00000 (x.go:5)	PCDATA	$0, $0
	0x0000 00000 (x.go:5)	MOVB	R0, "".~r1+12(FP)
	0x0004 00004 (x.go:5)	JMP	(R31)
	0x0008 00008 (x.go:5)	NOOP

that is, returning constant false (R0 is the zero register).

In MIPS.rules,

(SGTconst [c] (SRLconst _ [d])) && 0 <= int32(c) && uint32(d) <= 31 && 1<<(32-uint32(d)) <= int32(c) -> (MOVWconst [1])

This rule is problematic. SGTconst is to compare c with the shift _>>d, resulting 1 if c > (_>>d) regardless of the value of _. When c==0 and d==1, 1<<(32-1) <= int32(0) is true when compared as int32, turning to the wrong result. Will send a CL.

gopherbot · 2018-12-26T01:07:43Z

Change https://golang.org/cl/155798 mentions this issue: cmd/compile: fix MIPS SGTconst-with-shift rules

cherrymui · 2018-12-26T01:10:28Z

@anthonyfok could you test CL https://go-review.googlesource.com/c/go/+/155798 on a MIPS machine? Thanks!

anthonyfok · 2018-12-26T06:58:26Z

@cherrymui You are totally amazing! I think you have nailed the problem!
On both mips and mipsle, Go toolchain3 builds correctly after applying your CL:

(sid_mipsel-dchroot)foka@eller:~/git/go/src$ ./all.bash 
Building Go cmd/dist using /usr/lib/go-1.10.
Building Go toolchain1 using /usr/lib/go-1.10.
Building Go bootstrap cmd/go (go_bootstrap) using Go toolchain1.
Building Go toolchain2 using go_bootstrap and Go toolchain1.
Building Go toolchain3 using go_bootstrap and Go toolchain2.
Building packages and commands for linux/mipsle.

The tests are still being run. I will report back when all the test results are ready.

Thanks again! And wish you a very Happy Christmas season!

anthonyfok · 2018-12-26T15:13:05Z

@cherrymui The full build logs are in:

mips: Success! https://buildd.debian.org/status/fetch.php?pkg=golang-1.11&arch=mips&ver=1.11.4-3&stamp=1545828924&raw=0
mipsle: Success! https://buildd.debian.org/status/fetch.php?pkg=golang-1.11&arch=mipsel&ver=1.11.4-3&stamp=1545833561&raw=0
though the build failed later with testing: can't write /tmp/go-build192358536/b748/testlog.txt: write /tmp/go-build192358536/b748/testlog.txt: broken pipe, FAIL os/exec 1.722s, as described in os/exec: tests break testing package if testlog file is not file descriptor 3 #24285 and unlikely to be related to this issue.

cherrymui · 2018-12-26T15:22:06Z

@anthonyfok Thank you!

anthonyfok · 2018-12-28T08:51:58Z

@gopherbot please consider this for backport to 1.11, otherwise release-branch.go1.11 would fail to build on 32-bit MIPS. Thanks!

gopherbot · 2018-12-28T08:52:02Z

Backport issue(s) opened: #29442 (for 1.11).

Remember to create the cherry-pick CL(s) as soon as the patch is submitted to master, according to https://golang.org/wiki/MinorReleases.

gopherbot · 2018-12-28T15:17:39Z

Change https://golang.org/cl/155799 mentions this issue: [release-branch.go1.11] cmd/compile: fix MIPS SGTconst-with-shift rules

(SGTconst [c] (SRLconst _ [d])) && 0 <= int32(c) && uint32(d) <= 31 && 1<<(32-uint32(d)) <= int32(c) -> (MOVWconst [1]) This rule is problematic. 1<<(32-uint32(d)) <= int32(c) meant to say that it is true if c is greater than the largest possible value of the right shift. But when d==1, 1<<(32-1) is negative and results in the wrong comparison. Rewrite the rules in a more direct way. Updates #29402. Fixes #29442. Change-Id: I5940fc9538d9bc3a4bcae8aa34672867540dc60e Reviewed-on: https://go-review.googlesource.com/c/155798 Run-TryBot: Cherry Zhang <[email protected]> TryBot-Result: Gobot Gobot <[email protected]> Reviewed-by: Keith Randall <[email protected]> (cherry picked from commit 6a64efc) Reviewed-on: https://go-review.googlesource.com/c/155799 Reviewed-by: David Chase <[email protected]>

anthonyfok changed the title ~~go1.11.4 toolchain3 build fail with "slice bounds out of range" on Debian buildd~~ go1.11.4 toolchain3 build fail with "slice bounds out of range" on 32-bit MIPS on Debian buildd Dec 23, 2018

ALTree changed the title ~~go1.11.4 toolchain3 build fail with "slice bounds out of range" on 32-bit MIPS on Debian buildd~~ cmd/go: go1.11.4 toolchain3 build fail with "slice bounds out of range" on 32-bit MIPS on Debian buildd Dec 23, 2018

ALTree added the NeedsInvestigation Someone must examine and confirm this is a valid issue and not a duplicate of an existing one. label Dec 23, 2018

gopherbot closed this as completed in 6a64efc Dec 27, 2018

gopherbot mentioned this issue Dec 28, 2018

cmd/go: go1.11.4 toolchain3 build fail with "slice bounds out of range" on 32-bit MIPS on Debian buildd [1.11 backport] #29442

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golang locked and limited conversation to collaborators Dec 28, 2019

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cmd/go: go1.11.4 toolchain3 build fail with "slice bounds out of range" on 32-bit MIPS on Debian buildd #29402

cmd/go: go1.11.4 toolchain3 build fail with "slice bounds out of range" on 32-bit MIPS on Debian buildd #29402

anthonyfok commented Dec 23, 2018

randall77 commented Dec 23, 2018

anthonyfok commented Dec 25, 2018 •

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randall77 commented Dec 25, 2018

randall77 commented Dec 25, 2018

cherrymui commented Dec 26, 2018

gopherbot commented Dec 26, 2018

cherrymui commented Dec 26, 2018

anthonyfok commented Dec 26, 2018

anthonyfok commented Dec 26, 2018

cherrymui commented Dec 26, 2018

anthonyfok commented Dec 28, 2018

gopherbot commented Dec 28, 2018

gopherbot commented Dec 28, 2018

cmd/go: go1.11.4 toolchain3 build fail with "slice bounds out of range" on 32-bit MIPS on Debian buildd #29402

cmd/go: go1.11.4 toolchain3 build fail with "slice bounds out of range" on 32-bit MIPS on Debian buildd #29402

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