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24898 Commits

Author SHA1 Message Date
Robert Griesemer
92eb34b59a math/big: remove superfluous comparison
This is not a functional change.

Also:
- minor cleanups, better comments
- uniform spelling of noun "zeros" (per OED)

Fixes #11277.

Change-Id: I1726f358ce15907bd2410f646b02cf8b11b919cd
Reviewed-on: https://go-review.googlesource.com/11267
Reviewed-by: Alan Donovan <adonovan@google.com>
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-08-21 17:46:46 +00:00
Hyang-Ah (Hana) Kim
db5eb2a2c3 runtime/cgo: remove __stack_chk_fail_local
I cannot find where it's being used.

This addresses a duplicate symbol issue encountered in golang/go#9327.

Change-Id: I8efda45a006ad3e19423748210c78bd5831215e0
Reviewed-on: https://go-review.googlesource.com/13615
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-08-21 15:56:36 +00:00
Shawn Walker-Salas
d9e3d16796 runtime, syscall: remove unused bits from Solaris implementation
CL 9184 changed the runtime and syscall packages to link Solaris binaries
directly instead of using dlopen/dlsym but did not remove the unused (and
now broken) references to dlopen, dlclose, and dlsym.

Fixes #11923

Change-Id: I36345ce5e7b371bd601b7d48af000f4ccacd62c0
Reviewed-on: https://go-review.googlesource.com/13410
Reviewed-by: Aram Hăvărneanu <aram@mgk.ro>
2015-08-21 11:39:24 +00:00
Rob Pike
ae4dc8facb doc: fix typo in release notes
Change-Id: I5310cef72e714b22bcf2ae9e6fd85dbb7e8a15a2
Reviewed-on: https://go-review.googlesource.com/13787
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-08-21 05:41:17 +00:00
Rob Pike
f62b749ae2 all: fix some vet-caught formatting errors, mostly but not only in tests
Could go in 1.5, although not critical.
See also #12107

Change-Id: I7f1608b58581d21df4db58f0db654fef79e33a90
Reviewed-on: https://go-review.googlesource.com/13481
Reviewed-by: Dave Cheney <dave@cheney.net>
2015-08-21 05:37:36 +00:00
Robert Griesemer
39e77bff85 go/types: fix complex(a, b) for untyped arguments a, b
R=1.6

Fixes #11669.

Change-Id: Id39e5401e991e46f014eb16b747f5d9b7b55b46a
Reviewed-on: https://go-review.googlesource.com/12937
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-08-21 04:42:20 +00:00
Robert Griesemer
80eca3a98b go/types: don't crash for erroneous program involving a shift in a declaration cycle
R=1.6

Fixes #11347.

Change-Id: Ic6b09f38682500ffcc8d1f96e58f7237a7528806
Reviewed-on: https://go-review.googlesource.com/12812
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-08-21 04:42:02 +00:00
Robert Griesemer
f1b5bb9588 go/types: convert untyped switch expressions to default type
R=1.6

Fixes #11667.
Fixes #11687.

Change-Id: I060db212e8e0ee35fdefb4d482398f8f71650b38
Reviewed-on: https://go-review.googlesource.com/12713
Reviewed-by: Alan Donovan <adonovan@google.com>
2015-08-21 04:41:24 +00:00
Dominik Honnef
cb867d2fd6 os/user: don't depend on _SC_GETPW_R_SIZE_MAX on Linux
Even Linux systems may not have _SC_GETPW_R_SIZE_MAX if using a
different libc than glibc (e.g. musl). Instead of having special-cases
for the BSDs, handle -1 correctly by always using a default buffer size.

Fixes #11319.

Change-Id: I8b1b260eb9830e6dbe7667f3f33d115ae4de4ce8
Reviewed-on: https://go-review.googlesource.com/13772
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
2015-08-21 04:23:15 +00:00
Brad Fitzpatrick
7fb7f53232 encoding/base64: fix copy-paste-o bug in RawURLEncoding docs
Fixes #12244

Change-Id: Iee4e45d9bca0718c71fcc574bc51b2084c3dcb2a
Reviewed-on: https://go-review.googlesource.com/13783
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2015-08-21 02:42:11 +00:00
Andrew Gerrand
b733234856 net/http: document that [ListenAnd]Serve always returns a non-nil error
Fixes #12229

Change-Id: I243e39f67748e6754fb7726b21b3afc1ff436771
Reviewed-on: https://go-review.googlesource.com/13780
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-08-20 12:13:41 +00:00
David Glasser
7c154d973b cmd/go: fix vendoredImportPath comment
Change-Id: I1650124dd459dc401ccd73943ff7287b1b8c57e4
Reviewed-on: https://go-review.googlesource.com/13689
Reviewed-by: Andrew Gerrand <adg@golang.org>
2015-08-20 08:38:38 +00:00
Russ Cox
fa87cf83a6 doc: document Go 1.5 on release page
This makes sure the release page in the release will mention the release.

Fixes #12102.

Change-Id: I36befd7dba7ba9e70ae3335e21c8841179ac4eff
Reviewed-on: https://go-review.googlesource.com/13490
Reviewed-by: Rob Pike <r@golang.org>
2015-08-19 04:36:55 +00:00
Russ Cox
773b9b8452 net: respect go vs cgo resolver selection in all lookup routines
This is especially important for LookupAddr, which used to be pure Go
(lightweight, one goroutine per call) and without this CL is now
unconditionally cgo (heavy, one thread per call).

Fixes #12190.

Change-Id: I43436a942bc1838b024225893e156f280a1e80cf
Reviewed-on: https://go-review.googlesource.com/13698
Reviewed-by: Rob Pike <r@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-08-19 04:20:37 +00:00
Russ Cox
18d27b2d75 net: force LookupAddr results to be rooted DNS paths when using cgo
Go 1.4 and before have always returned DNS names with a trailing dot
for reverse lookups, as they do for basically all other routines returning
DNS names. Go 1.4 and before always implemented LookupAddr using
pure Go (not C library calls).

Go 1.5 added the ability to make a C library call to implement LookupAddr.
Unfortunately the C library call returns a DNS name without a trailing dot
(an unrooted name), meaning that if turn off cgo during make.bash then
you still get the rooted name but with cgo on you get an unrooted name.
The unrooted name is inconsistent with the pure Go implementation
and with all previous Go releases, so change it to a rooted name.

Fixes #12189.

Change-Id: I3d6b72277c121fe085ea6af30e5fe8019fc490ad
Reviewed-on: https://go-review.googlesource.com/13697
Reviewed-by: Rob Pike <r@golang.org>
2015-08-19 04:20:27 +00:00
Russ Cox
b711f5ad8f net: document GODEBUG=netdns=xxx settings
Fixes #12191.

Change-Id: I5c7659ccb0566dad3613041d9e76be87ceacae61
Reviewed-on: https://go-review.googlesource.com/13700
Reviewed-by: Rob Pike <r@golang.org>
2015-08-19 04:08:34 +00:00
Rob Pike
54eb9efb70 doc: fix typos in go1.5.html
Thanks to Nathan Youngman for spotting them.

Change-Id: I1856527af66a5d1965265ec3dcd639d3f6d74bcc
Reviewed-on: https://go-review.googlesource.com/13711
Reviewed-by: Russ Cox <rsc@golang.org>
2015-08-19 03:49:02 +00:00
Russ Cox
16c3838cf6 doc/go1.5.html: refer to ppc64 as 64-bit PowerPC, not Power 64
Saying "Power 64" was wrong for reasons I don't remember.
(Those reasons are why we stopped using GOARCH=power64.)

Change-Id: Ifaac78d5733bfc780df01b1a66da766af0b17726
Reviewed-on: https://go-review.googlesource.com/13675
Reviewed-by: Rob Pike <r@golang.org>
2015-08-19 03:28:57 +00:00
Russ Cox
54575631a5 doc: adjust binary install page supported system list
Make clear that this list is the list of supported systems
for binary distributions, and that other systems may be
able to build the distribution from source, in addition
to using gccgo.

Drop freebsd/arm from the list on this page.
We have never issued a binary distribution for freebsd/arm,
and we're not going to start in Go 1.5, since we don't even
have a working builder for it.

Drop freebsd/386 from the list on the page,
because we are unable to build binary distributions, per adg.

I think the wording here should probably be revised further,
but not now.

Change-Id: Ib43b6b64f5c438bfb9aa4d3daa43393f1e33b71f
Reviewed-on: https://go-review.googlesource.com/13690
Reviewed-by: Andrew Gerrand <adg@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
2015-08-19 03:28:41 +00:00
Russ Cox
6f0c7df8ed cmd/vet: power64 is now ppc64
This was missed when we did the rename months ago
because cmd/vet did not live in the main tree.
Now vet's asmdecl checks will apply to ppc64 assembly too.

Change-Id: I687cba89fef702f29dd118de76a7ca1041c414f6
Reviewed-on: https://go-review.googlesource.com/13677
Reviewed-by: Andrew Gerrand <adg@golang.org>
2015-08-18 17:00:59 +00:00
Russ Cox
5acde2d5aa cmd/go: really skip TestNoteReading on linux/ppc64le
Change-Id: Iaeba7c55bbb9e11ac30f3b61369aa597acc30190
Reviewed-on: https://go-review.googlesource.com/13691
Reviewed-by: Russ Cox <rsc@golang.org>
2015-08-18 15:41:54 +00:00
Russ Cox
92c984e064 cmd/go: disable TestNoteReading on solaris, linux/ppc64le
Update #11184 (linux/ppc64).
Filed #12178 (solaris) for Go 1.6.

Change-Id: I9e3a456aaccb49590ad4e14b53ddfefca5b0801c
Reviewed-on: https://go-review.googlesource.com/13679
Reviewed-by: Russ Cox <rsc@golang.org>
2015-08-18 15:25:19 +00:00
Russ Cox
f68d1df6b9 cmd/compile: fix interaction between GOEXPERIMENT=fieldtrack and race detector
Tested by hand.
Only lines of code changing are protected by Fieldtrack_enabled > 0,
which is never true in standard Go distributions.

Fixes #12171.

Change-Id: I963b9997dac10829db8ad4bfc97a7d6bf14b55c6
Reviewed-on: https://go-review.googlesource.com/13676
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-08-18 14:36:01 +00:00
Russ Cox
9e26cde786 cmd/go: fix vendor-related index out of range panic on bad file tree
Fixes #12156.

Change-Id: I2d71163b98bcc770147eb9e78dc551a9d0b5b817
Reviewed-on: https://go-review.googlesource.com/13674
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-08-18 13:53:28 +00:00
Russ Cox
d2cf46dedf cmd/go: fix spurious rebuild of binaries using cgo on OS X
The text segment starts farther into the binary when using
external linking on the mac. Test and fix.

Fixes #12173.

Change-Id: I1f0c81814bf70cd9decfceac3022784f4608eeef
Reviewed-on: https://go-review.googlesource.com/13672
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-08-18 13:51:16 +00:00
Russ Cox
3f016215a8 cmd/yacc: fix compile error in empty grammar
Fixes #12154.

Change-Id: I1e6d1a3479a8a6fc8f53aebd18fb142506110809
Reviewed-on: https://go-review.googlesource.com/13673
Reviewed-by: Rob Pike <r@golang.org>
2015-08-18 13:50:36 +00:00
Brad Fitzpatrick
d931716cde net/http: fix races cloning TLS config
Found in a Google program running under the race detector.
No test, but verified that this fixes the race with go run -race of:

	package main

	import (
	        "crypto/tls"
	        "fmt"
	        "net"
	        "net/http"
	        "net/http/httptest"
	)

	func main() {
	        for {
	                ts := httptest.NewTLSServer(http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {}))
	                conf := &tls.Config{} // non-nil
	                a, b := net.Pipe()
	                go func() {
	                        sconn := tls.Server(a, conf)
	                        sconn.Handshake()
	                }()
	                tr := &http.Transport{
	                        TLSClientConfig: conf,
	                }
	                req, _ := http.NewRequest("GET", ts.URL, nil)
	                _, err := tr.RoundTrip(req)
	                println(fmt.Sprint(err))
	                a.Close()
	                b.Close()
	                ts.Close()
	        }
	}

Also modified cmd/vet to report the copy-of-mutex bug statically
in CL 13646, and fixed two other instances in the code found by vet.
But vet could not have told us about cloneTLSConfig vs cloneTLSClientConfig.

Confirmed that original report is also fixed by this.

Fixes #12099.

Change-Id: Iba0171549e01852a5ec3438c25a1951c98524dec
Reviewed-on: https://go-review.googlesource.com/13453
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Russ Cox <rsc@golang.org>
2015-08-18 00:55:16 +00:00
Ian Lance Taylor
d7aae33aef doc: only the Logger.SetOutput method is new in Go 1.5
The SetOutput function has been there since Go 1.

Fixes #12162.

Change-Id: I66210374877581e42689f9943532141659a55ca7
Reviewed-on: https://go-review.googlesource.com/13637
Reviewed-by: Rob Pike <r@golang.org>
2015-08-17 15:29:23 +00:00
Matt Bostock
3c43158087 sort: Fix typo in Stable() comment
Correct 'an' to 'on' in the comment above the Stable() function.

Change-Id: I714e38b2d3a79dfd539d5368967d1c6b519cb948
Reviewed-on: https://go-review.googlesource.com/13662
Reviewed-by: Rob Pike <r@golang.org>
2015-08-17 06:58:16 +00:00
Dave Cheney
467a2cb73c cmd/compile/internal/arm64: remove Reginuse check in clearfat
Fixes golang/go#12133

CL 13630 fixed the use of a stale reg[] array in the various arch
backends which was causing the check in clearfat to pass
unconditionally on arm64.

With this check fixed, arm64 now considers REGRT1 to always be in use
as it is part of the reserved register set, see arm64/gsubr.go.

However, ppc64 does not consider REGRT1 and REGRT2 to be part of its
reserved set, so its identical clearfat check passes.

This CL removes the Reginuse check inside clearfat as REGRT1 is
guarenteed always be free on arm64.

Change-Id: I4719150d3c3378fae155b863c474529df18d4c17
Reviewed-on: https://go-review.googlesource.com/13650
Reviewed-by: Russ Cox <rsc@golang.org>
2015-08-16 00:29:39 +00:00
Dmitry Vyukov
e8c4a5b893 cmd/trace: fix static file reference
Use runtime.GOROOT instead of os.Getenv("GOROOT") to reference
trace-viewer html file. GOROOT env var is not necessary set,
runtime.GOROOT has a default value for such case.

Change-Id: I906a720f6822915bd9575756e6cbf6d622857c2b
Reviewed-on: https://go-review.googlesource.com/13593
Reviewed-by: Russ Cox <rsc@golang.org>
2015-08-15 17:38:56 +00:00
Rahul Chaudhry
5bf1369c9b cmd/go: make "go test" recognize -exec flag again.
Fixes #12144.

Change-Id: I112c6517371215c9797db8f1dffca0f3047c39e3
Reviewed-on: https://go-review.googlesource.com/13633
Reviewed-by: Russ Cox <rsc@golang.org>
2015-08-15 17:38:41 +00:00
Keith Randall
e97ab0a0ac cmd/compile: remove stale register use array
The reg[] array in .../gc is where truth lies.  The copy in .../ARCH
is incorrect as it is mostly not updated to reflect regalloc decisions.

This bug was introduced in the rewrite
https://go-review.googlesource.com/#/c/7853/.  The new reg[] array was
introduced in .../gc but not all of the uses were removed in the
.../ARCH directories.

Fixes #12133

Change-Id: I6364fc403cdab92d802d17f2913ba1607734037c
Reviewed-on: https://go-review.googlesource.com/13630
Reviewed-by: Russ Cox <rsc@golang.org>
2015-08-15 17:37:14 +00:00
Dave Cheney
cda1fc0071 cmd/compile/internal/ppc64: disable DUFFZERO
Update #12108

If DUFFZERO is used within a tail call method it will overwrite the
link register.

Change-Id: I6abd2fde0f0ad909ccd55eb119b992673a74f0e2
Reviewed-on: https://go-review.googlesource.com/13570
Reviewed-by: Russ Cox <rsc@golang.org>
2015-08-12 20:31:26 +00:00
Russ Cox
58035ec8ee cmd/go: run test binaries in original environment
Fixes #12096.
Followup to CL 12483, which fixed #11709 and #11449.

Change-Id: I9031ea36cc60685f4d6f65c39f770c89b3e3395a
Reviewed-on: https://go-review.googlesource.com/13449
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-08-11 20:46:22 +00:00
Russ Cox
28fb0d8023 cmd/go: fix addition of "math" dependency for arm binaries
p.ImportPath is the directory-derived path (like cmd/go).
p.Name is the actual package name.

Fixes #12089.

Change-Id: Ief76d42a85f811b0dfe2218affb48551527a7d44
Reviewed-on: https://go-review.googlesource.com/13530
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2015-08-11 19:13:12 +00:00
Russ Cox
8ce80ce87d cmd/link: make -a output not crash
Fixes #12107.

Change-Id: I62f1b6ac9fb6f2cfa3472253dc1c6f7b7d2a6faf
Reviewed-on: https://go-review.googlesource.com/13448
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2015-08-11 19:12:59 +00:00
David Symonds
1052b43213 net/mail: fix build.
Change-Id: I8f5c72c6c0db015c06d564523bab35d97d934578
Reviewed-on: https://go-review.googlesource.com/13510
Reviewed-by: Michael McGreevy <mcgreevy@golang.org>
Reviewed-by: David Symonds <dsymonds@golang.org>
2015-08-11 06:42:12 +00:00
David Symonds
1d75b40de8 net/mail: avoid panic in (*Address).String for malformed addresses.
Fixes #12098.

Change-Id: I190586484cd34856dccfafaba60eff0197c7dc20
Reviewed-on: https://go-review.googlesource.com/13500
Reviewed-by: Rob Pike <r@golang.org>
2015-08-11 05:07:30 +00:00
Rob Pike
546836556d cmd/yacc: use %q to print strings in Toknames
Fixes #12086

Belongs in 1.5

There remains a question of why the Statenames table's elements
are not printed. What purpose does that serve?

Change-Id: I83fd57b81d5e5065c3397a66ed457fc0d1c041bd
Reviewed-on: https://go-review.googlesource.com/13462
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Andrew Gerrand <adg@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2015-08-11 00:26:05 +00:00
Andrew Gerrand
8389e7cfa9 doc: link to Go 1.5 release notes from "project" page
Update issue #12102.

Change-Id: I9cafb284a848cc053bc7e5479c53ebf889b6d4d9
Reviewed-on: https://go-review.googlesource.com/13480
Reviewed-by: Rob Pike <r@golang.org>
2015-08-11 00:02:29 +00:00
Rob Pike
fe3d8d4db0 fmt: don't unread eof scanning %x
When scanning a hex byte at EOF, the code was ungetting the eof,
which backed up the input and caused double-scanning of a byte.

Delete the call to UnreadRune.

This line appeared in 1.5 for some reason; it was not in 1.4 and
should be removed again for 1.5

Fixes #12090.

Change-Id: Iad1ce8e7db8ec26615c5271310f4b0228cca7d78
Reviewed-on: https://go-review.googlesource.com/13461
Reviewed-by: Andrew Gerrand <adg@golang.org>
2015-08-10 03:34:48 +00:00
Dave Cheney
e7f4df7332 doc: NaCl requires pepper 41
Fixes #12062
Updates #11961

The sRPC nameservice was removed in pepper 42. For Go 1.5 stipulate
that NaCl requires pepper 41 only.

Change-Id: Ic88ba342d41f673391efaa96fb581712fa10a0fd
Reviewed-on: https://go-review.googlesource.com/13341
Reviewed-by: Andrew Gerrand <adg@golang.org>
2015-08-10 02:15:29 +00:00
Russ Cox
3ae17043f7 runtime: make sure heapBitsBulkBarrier cannot be preempted
Changes the torture test in #12068 from failing about 1/10 times
to not failing in almost 2,000 runs.

This was only happening in -race mode because functions are
bigger in -race mode, so a few of the helpers for heapBitsBulkBarrier
were not being inlined, and they were not marked nosplit,
so (only in -race mode) the write barrier was being preempted by GC,
causing missed pointer updates.

Filed issue #12069 for diagnosis of any other similar errors.

Fixes #12068.

Change-Id: Ic174d9b050ba278b18b08ab0d85a73c33bd5b175
Reviewed-on: https://go-review.googlesource.com/13364
Reviewed-by: Austin Clements <austin@google.com>
2015-08-07 17:55:26 +00:00
Russ Cox
4a19081358 runtime: run on GOARM=5 and GOARM=6 uniprocessor freebsd/arm systems
Also, crash early on non-Linux SMP ARM systems when GOARM < 7;
without the proper synchronization, SMP cannot work.

Linux is okay because we call kernel-provided routines for
synchronization and barriers, and the kernel takes care of
providing the right routines for the current system.
On non-Linux systems we are left to fend for ourselves.

It is possible to use different synchronization on GOARM=6,
but it's too late to do that in the Go 1.5 cycle.
We don't believe there are any non-Linux SMP GOARM=6 systems anyway.

Fixes #12067.

Change-Id: I771a556e47893ed540ec2cd33d23c06720157ea3
Reviewed-on: https://go-review.googlesource.com/13363
Reviewed-by: Austin Clements <austin@google.com>
2015-08-07 17:39:07 +00:00
Andrew Gerrand
0cd2999c3b cmd/go: replace code.google.com examples in docs with relevant repos
Change-Id: I625c9df161da2febdca85741c75fc32d4bef420b
Reviewed-on: https://go-review.googlesource.com/13344
Reviewed-by: Rob Pike <r@golang.org>
2015-08-07 05:52:11 +00:00
Andrew Gerrand
abe70aff0e doc: tweak phrasing in Go 1.5 release notes
Change-Id: I6bea045bb1cef15e6d9d3b4e6e6b4ae91f7bb941
Reviewed-on: https://go-review.googlesource.com/13345
Reviewed-by: Rob Pike <r@golang.org>
2015-08-07 05:51:33 +00:00
Russ Cox
4b145d42e9 doc: do not call WaitGroup a function
Fixes #12060.

Change-Id: Ie2fd10bedded1a4f4e0daa0c0c77ecd898480767
Reviewed-on: https://go-review.googlesource.com/13324
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-08-06 20:37:38 +00:00
Austin Clements
ad731887a7 runtime: call goexit1 instead of goexit
Currently, runtime.Goexit() calls goexit()—the goroutine exit stub—to
terminate the goroutine. This *mostly* works, but can cause a
"leftover stack barriers" panic if the following happens:

1. Goroutine A has a reasonably large stack.

2. The garbage collector scan phase runs and installs stack barriers
   in A's stack. The top-most stack barrier happens to fall at address X.

3. Goroutine A unwinds the stack far enough to be a candidate for
   stack shrinking, but not past X.

4. Goroutine A calls runtime.Goexit(), which calls goexit(), which
   calls goexit1().

5. The garbage collector enters mark termination.

6. Goroutine A is preempted right at the prologue of goexit1() and
   performs a stack shrink, which calls gentraceback.

gentraceback stops as soon as it sees goexit on the stack, which is
only two frames up at this point, even though there may really be many
frames above it. More to the point, the stack barrier at X is above
the goexit frame, so gentraceback never sees that stack barrier. At
the end of gentraceback, it checks that it saw all of the stack
barriers and panics because it didn't see the one at X.

The fix is simple: call goexit1, which actually implements the process
of exiting a goroutine, rather than goexit, the exit stub.

To make sure this doesn't happen again in the future, we also add an
argument to the stub prototype of goexit so you really, really have to
want to call it in order to call it. We were able to reliably
reproduce the above sequence with a fair amount of awful code inserted
at the right places in the runtime, but chose to change the goexit
prototype to ensure this wouldn't happen again rather than pollute the
runtime with ugly testing code.

Change-Id: Ifb6fb53087e09a252baddadc36eebf954468f2a8
Reviewed-on: https://go-review.googlesource.com/13323
Reviewed-by: Russ Cox <rsc@golang.org>
2015-08-06 20:21:05 +00:00
Russ Cox
26baed6af7 runtime: fix race that dropped GoSysExit events from trace
This makes TestTraceStressStartStop much less flaky.
Running under stress, it changes the failure rate from
above 1/100 to under 1/50000. That very unlikely
failure happens when an unexpected GoSysExit is
written. Not sure how that happens yet, but it is much
less important.

Fixes #11953.

Change-Id: I034671936334b4f3ab733614ef239aa121d20247
Reviewed-on: https://go-review.googlesource.com/13321
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
2015-08-06 19:29:09 +00:00