Linux's execve has (at the time of writing, and since v2.6.30) a bug when it ran
concurrently with clone, in that it would fail to set up some datastructures if
the thread count before and after some steps differed. This is described better
and in more detail by Colin King in Launchpad¹ and kernel² bugs. When a program
written in Go runtime.Exec's a setuid binary, this issue may cause the resulting
process to not have the expected uid. This patch works around the issue by using
a mutex to serialize exec and clone.

1. https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1672819
2. https://bugzilla.kernel.org/show_bug.cgi?id=195453

Fixes #19546

Change-Id: I126e87d1d9ce3be5ea4ec9c7ffe13f92e087903d
Reviewed-on: https://go-review.googlesource.com/43713Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #19285

Change-Id: I11e864eff9980dec8247c47e4c600f76602e7ada
Reviewed-on: https://go-review.googlesource.com/46092Reviewed-by: Ian Lance Taylor <iant@golang.org>

I updated my tool to deal with Github-only contributors without Gerrit
accounts. The "dep" repo is the main source of these, although there
are a few others.

Add Alexander Kauer (individual CLA)
Add Anders Pearson (individual CLA)
Add Brad Whitaker (corporate CLA for Fastly, Inc.)
Add Daisuke Fujita (individual CLA)
Add Daniel Upton (individual CLA)
Add David Volquartz Lebech (individual CLA)
Add Emilien Kenler (individual CLA)
Add Fazal Majid (corporate CLA for Apsalar)
Add Gustav Westling (individual CLA)
Add Henry Chang (individual CLA)
Add Jianqiao Li (corporate CLA for Google Inc.)
Add Jin-wook Jeong (individual CLA)
Add Kaleb Elwert (individual CLA)
Add Kashav Madan (individual CLA)
Add Koki Ide (individual CLA)
Add Konstantin (individual CLA)
Add Kyle Jones (individual CLA)
Add Leon Klingele (individual CLA)
Add Martin Olsen (individual CLA)
Add Máximo Cuadros Ortiz (individual CLA)
Add Miguel Molina (individual CLA)
Add Nathaniel Cook (individual CLA)
Add Neil Lyons (individual CLA)
Add Nick Robinson (individual CLA)
Add Niranjan Godbole (individual CLA)
Add Oleg Bulatov (individual CLA)
Add Oliver Tonnhofer (individual CLA)
Add Paul Querna (individual CLA)
Add Peter Bourgon (individual CLA)
Add Quentin Renard (individual CLA)
Add Ray Tung (individual CLA)
Add Rob Phoenix (individual CLA)
Add Ryan Boehning (individual CLA)
Add Sakeven Jiang (individual CLA)
Add Stephen Searles (individual CLA)
Add Steven Wilkin (individual CLA)
Add Sunny (individual CLA)
Add Ted Kornish (individual CLA)
Add Victor Vrantchan (individual CLA)
Add Wander Lairson Costa (individual CLA)
Add Zakatell Kanda (individual CLA)

Updates #12042

Change-Id: I2e4828cce880965c77b374c1e115d0e437d108c7
Reviewed-on: https://go-review.googlesource.com/46090Reviewed-by: Ian Lance Taylor <iant@golang.org>

This certainly won't get inlined right now, but in the spirit of
making this more robust, we have to disable inlining because inlining
would defeat the purpose of separating forkAndExecInChild1 into a
separate function.

Updates #20732.

Change-Id: I736c3f909cc42c5f5783740c2e19ba4827c7c2ec
Reviewed-on: https://go-review.googlesource.com/46174
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Currently, CLONE_VFORK is used without much regard to the stack. This
is dangerous, because anything the child does to the stack is visible
to the parent. For example, if the compiler were to reuse named stack
slots (which it currently doesn't do), it would be easy for the child
running in the same stack frame as the parent to corrupt local
variables that the parent then depended on. We're not sure of anything
specific going wrong in this code right now, but it is at best a
ticking time bomb.

CLONE_VFORK can only safely be used if we ensure the child does not
execute in any of the active stack frames of the parent. This commit
implements this by arranging for the parent to return immediately from
the frame the child will operate in, and for the child to never return
to the frame the parent will operate in.

Fixes #20732.

Change-Id: Iad5b4ddc2b994c082bd278bfd52ef53bd38c037f
Reviewed-on: https://go-review.googlesource.com/46173
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

This reverts commit 3d13b5e0.

Reason for revert: the new TestHttpsInsecure test breaks two darwin builders, the android builders, and one plan9 builder.

Change-Id: I09158e7d1bd2b3ffda57e7f2350f34eb9b62e784
Reviewed-on: https://go-review.googlesource.com/46158Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Updating to commit fffc5831a499a958516664a34cb7ba2b9e228793
from github.com/google/pprof

Fixes #19380

Change-Id: I7a0c64101f42b494c4a469c41628374272eccf95
Reviewed-on: https://go-review.googlesource.com/46155
Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This adds a qualified mention of golang/dep to the FAQ.

Fixes #19049

Change-Id: I42a114a008a6ca1250d849872dd98fd6523fa659
Reviewed-on: https://go-review.googlesource.com/46005Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

If you have BenchmarkX1 with sub-benchmark Y
and you have BenchmarkX2 with no sub-benchmarks,
then

	go test -bench=X/Y

runs BenchmarkX1 once with b.N=1 (to find out about Y)
and then not again, because it has sub-benchmarks,
but arguably also because we're interested in Y.

In contrast, it runs BenchmarkX2 in full, even though clearly
that is not relevant to the match X/Y. We do have to run X2
once with b.N=1 to probe for having X2/Y, but we should not
run it with larger b.N.

Fixes #20589.

Change-Id: Ib86907e844f34dcaac6cd05757f57db1019201d0
Reviewed-on: https://go-review.googlesource.com/46031
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>

Updates http2 to x/net/http2 git rev 3d7ac2a5d for:

    http2: fix Server race
    https://golang.org/cl/20704

Fixes #20704

Change-Id: I803288f94a8a462ad0960b0c29c2dfee27b9f1ae
Reviewed-on: https://go-review.googlesource.com/46093
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Tom Bergan <tombergan@google.com>
Reviewed-by: Tom Bergan <tombergan@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #19544.

Change-Id: I5df67383e9471f030ddafabadf2bc19ce6816f0f
Reviewed-on: https://go-review.googlesource.com/46002Reviewed-by: Matthew Dempsky <mdempsky@google.com>

This is a runtime version of sync.RWMutex that can be used by code in
the runtime package. The type is not quite the same, in that the zero
value is not valid.

For future use by CL 43713.

Updates #19546

Change-Id: I431eb3688add16ce1274dab97285f555b72735bf
Reviewed-on: https://go-review.googlesource.com/45991Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Austin Clements <austin@google.com>

This doesn't change the existing restriction with disallows
spaces in import paths (as found in an import declaration).
It simply permits packages to be under a directory name that
may contain spaces.

Verified manually that it works. This could use a test, but the
change is trivial. We also can't use the existing test framework
(under test/) because the way those tests are run with test/run.go,
the mechanims for compiling a directory, even if it contains blanks
it its name, does't produce compiler paths with blanks
(the compilation is local).

Fixes #20306.

Change-Id: I6cbffb86c3394347897c3c94b110da0aadc5bfdf
Reviewed-on: https://go-review.googlesource.com/46001Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

Changed link for cover from x-tools to correct

Fix #20662

Change-Id: I9b839ed952e9abb12b3d1655ac4cf5976f374a4b
Reviewed-on: https://go-review.googlesource.com/46012Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: Ia5c8fcff000bf3d369d42407342c470ea92e18da
Reviewed-on: https://go-review.googlesource.com/46006Reviewed-by: Alberto Donizetti <alb.donizetti@gmail.com>

OpenBSD no longer has procfs.

Based on a patch by Matthieu Sarter.

Fixes #19453.

Change-Id: Ia09d16f8a1cbef2f8cc1c5f49e9c61ec7d026a40
Reviewed-on: https://go-review.googlesource.com/46004
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Round doesn't always round away from zero.

Feel free to suggest better wording.

Change-Id: I52b3815013fff4c656ae8d861521c342bc4135b7
Reviewed-on: https://go-review.googlesource.com/46032Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Updates http2 to x/net/http2 git rev 973f3f3 for:

   http2: make Transport treat http.NoBody like it were nil
   https://golang.org/cl/45993

Updates #18891

Change-Id: I846ccf286992ed2c6249014e51fdeb40b35e50ed
Reviewed-on: https://go-review.googlesource.com/46000
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Only forget about it if the context timed out, as the comment says.

Fixes #20703.

Change-Id: Ie6234f1a32f85e6bfd052dc24a33aa63b8883c37
Reviewed-on: https://go-review.googlesource.com/45999
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Per email from acoshift.

Change-Id: Ieb79244d17623e112a385e6b43843d3ffb185cf6
Reviewed-on: https://go-review.googlesource.com/45995Reviewed-by: Matt Layher <mdlayher@gmail.com>

Fixes #20702

Change-Id: Id90f08c33e3ccc37794b47fcd27f6c3f2f41c634
Reviewed-on: https://go-review.googlesource.com/46011Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Make it clearer that -test=X/Y runs all the tests matching X,
even if they don't have sub-tests matching Y.

Fixes #20589.

Change-Id: Ic27e89e748d60f67b50c68445ec0480066bdf207
Reviewed-on: https://go-review.googlesource.com/46030
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The ascii85, base32 and base64 packages all contain a test called
TestDecoderBuffering.  Each of these tests contain a loop that ignores
the error returned from the Read method of their decoders.  The result
being that the tests loop for ever if the decoders actually return an
error.  This commit fixes the issue by terminating the loops if an error
occurs and failing the tests with a suitable error message.

Change-Id: Idb385673cf9f3f6f8befe4288b4be366ab0985fd
Reviewed-on: https://go-review.googlesource.com/46010Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

If an image has been cropped horizontally, writeImageBlock detects that
its width and Stride differ and acts accordingly.

However, if an image has been cropped vertically, trimming from the
bottom, the whole original image will be written in place.  This results
in more data in the LZW stream than necessary, and many decoders
including image/gif's itself will fail to load.

Fixes #20692

Change-Id: Id332877e31bcf3729c89d8a50c1be0464028d82e
Reviewed-on: https://go-review.googlesource.com/45972
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
Run-TryBot: Nigel Tao <nigeltao@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Nigel Tao <nigeltao@golang.org>

Add Adam Eijdenberg (individual CLA)
Add Agis Anastasopoulos (individual CLA)
Add Alexander Guz (individual CLA)
Add Alexander Kucherenko (individual CLA)
Add Alexander Polcyn (corporate CLA for Google Inc.)
Add Alexis Hildebrandt (individual CLA)
Add Alexis Hunt (corporate CLA for Google Inc.)
Add Andrew Jackura (corporate CLA for Google Inc.)
Add Anthony Voutas (individual CLA)
Add Antoine Martin (individual CLA)
Add Antonio Troina (individual CLA)
Add Bill Prin (corporate CLA for Google Inc.)
Add Brad Jones (corporate CLA for Google Inc.)
Add Chris Raynor (corporate CLA for Google Inc.)
Add Chris Roche (individual CLA)
Add Daker Fernandes Pinheiro (corporate CLA for Intel Corporation)
Add Dave MacFarlane (individual CLA)
Add Derek McGowan (individual CLA)
Add Di Xiao (corporate CLA for Google Inc.)
Add Doug Fawley (corporate CLA for Google Inc.)
Add Eric Chiang (individual CLA)
Add Eyal Posener (individual CLA)
Add Fabian Zaremba (individual CLA)
Add Fredrik Forsmo (individual CLA)
Add Hang Qian (individual CLA)
Add Hsin Tsao (corporate CLA for Google Inc.)
Add James Cowgill (individual CLA)
Add James Hartig (individual CLA)
Add James Myers (individual CLA)
Add Jason Chu (individual CLA)
Add Jay Conrod (corporate CLA for Google Inc.)
Add Jeff (Zhefu) Jiang (corporate CLA for Google Inc.)
Add Jeffrey H (individual CLA)
Add Jianing Yu (corporate CLA for Google Inc.)
Add Josh Deprez (individual CLA)
Add Julian Pastarmov (corporate CLA for Google Inc.)
Add Kai Trukenmüller (individual CLA)
Add Kim Yongbin (individual CLA)
Add Kodie Goodwin (individual CLA)
Add Lev Shamardin (individual CLA)
Add Lucas Bremgartner (individual CLA)
Add Ludi Rehak (individual CLA)
Add Lukasz Milewski (individual CLA)
Add Magnus Hiie (corporate CLA for Teleport Inc.)
Add Marko Mudrinic (individual CLA)
Add Martin Habbecke (corporate CLA for Google Inc.)
Add Martin Hoefling (individual CLA)
Add Martin Probst (individual CLA)
Add Masahiro Furudate (individual CLA)
Add Masahiro Wakame (individual CLA)
Add Masaki Yoshida (individual CLA)
Add Mathias Hall-Andersen (individual CLA)
Add Maxime de Roucy (individual CLA)
Add Nathan Humphreys (individual CLA)
Add Neuman Vong (individual CLA)
Add Pablo Lalloni (individual CLA)
Add Pavlo Sumkin (individual CLA)
Add Peter Morjan (individual CLA)
Add Piers (individual CLA)
Add Qiuxuan Zhu (individual CLA)
Add Richard Dingwall (individual CLA)
Add Rick Sayre (individual CLA)
Add Sascha Brawer (individual CLA)
Add Sergey Mishin (individual CLA)
Add Spencer Tung (corporate CLA for Google Inc.)
Add Steven Erenst (individual CLA)
Add Thomas Bouldin (corporate CLA for Google Inc.)
Add Tobias Klauser (individual CLA)
Add Tonis Tiigi (individual CLA)
Add Trung Nguyen (individual CLA)
Add Vikas Kedia (corporate CLA for Google Inc.)
Add Vladimir Varankin (individual CLA)
Add Yestin Sun (individual CLA)
Add acoshift (individual CLA)

Updates #12042

Change-Id: I5e3ba25f310fc89ae391e5abb308e137d56c9148
Reviewed-on: https://go-review.googlesource.com/45990Reviewed-by: Ian Lance Taylor <iant@golang.org>

In some cases the netpoll code can cause a spurious wakeup. This is
normally harmless, as the woken up code simply retries the operation.
However, for connect, the test we were using to see whether the
connect had succeeded (setsockopt(SO_ERROR)) was not reliable in the
case of a spurious wakeup.  Change to using a reliable test (getpeername).
On Darwin we used a different technique: a second call to connect;
change Darwin to use getpeername as well.

Return the result of getpeername to avoid having to call it twice.

Fixes #19289.

Change-Id: I119ec8e7a41f482f1e590d4c65a37f6103fa22d9
Reviewed-on: https://go-review.googlesource.com/45815
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Verified by manually enabling debug mode and running make.bash.

Fixes #20684.

Change-Id: I041f2ca6ef1d4198815724d98f61511072d63581
Reviewed-on: https://go-review.googlesource.com/45971
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Minimal reconstruction of reported failure case.

Manually verified that test fails with CL 45911 reverted.

Change-Id: Ia5d11500d91b46ba1eb5d841db3987edb9136c39
Reviewed-on: https://go-review.googlesource.com/45970
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Robert Griesemer <gri@golang.org>

Change-Id: I7776547332066e1d7651e9aa06eec301dfaf38bc
Reviewed-on: https://go-review.googlesource.com/45892Reviewed-by: Rob Pike <r@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #14270.

Change-Id: Iaf2496a24b1aba443391b90951cef472add73f13
Reviewed-on: https://go-review.googlesource.com/45950
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

The existing docs states that, get looks for a branch or tag
that matches the locally installed version of Go.
First, this is only working for "go1", so it could be confusing.
Second, "If no such version exists it retrieves the most recent
version of the package". It's more the default branch, by git defaults,
rather than most recent version.

This should address the potential unclear parts.

Fixes #20320

Change-Id: Id7d727d88dc350c9902974b64fa28c3766f7e245
Reviewed-on: https://go-review.googlesource.com/45890Reviewed-by: Ian Lance Taylor <iant@golang.org>

Change-Id: I8aa070f8093e80ba19f0546d7447caf847a2b388
Reviewed-on: https://go-review.googlesource.com/45912Reviewed-by: Ian Lance Taylor <iant@golang.org>

This reverts commit edad59cf.

Fixes #20682.

Change-Id: If998c8b4bf177d5da9e26f75579bd5497ec86d38
Reviewed-on: https://go-review.googlesource.com/45911
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

Change-Id: I64d32fd308f2b7968dfaf11cdc85ab1952170868
Reviewed-on: https://go-review.googlesource.com/45891Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Updates #20587

Change-Id: I428d20bf8512ba859cc63c439bd5d92a5173fad2
Reviewed-on: https://go-review.googlesource.com/45910Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Fixes #20618

Change-Id: I90712bd76d9d47f29221bc298c69737ebee25c12
Reviewed-on: https://go-review.googlesource.com/45814Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Some of the _test.go files in the encoding packages contain a private
function called testEqual that calls testing.Errorf if the arguments
passed to it are unequal.   The line numbers output by such calls to
Errorf identify the failure as being in testEqual itself which is not
very useful.  This commit fixes the problem by adding a call to the
new t.Helper method in each of the testEqual functions.  The line
numbers output when errors do occur now identify the real source of
the error.

Change-Id: I582d1934f40ef2b788116c3811074c67ea882021
Reviewed-on: https://go-review.googlesource.com/45871Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

They were failing when run on 32bit RFS, with 32bit gdb.
(mips64 builder now has 64bit RFS, with gdb 7.9.)
Leaving TestGdbPythonCgo disabled, it behaves as described in #18784.

Fixes #18173

Change-Id: I3c438cd5850b7bfd118ac6396f40c1208bac8c2d
Reviewed-on: https://go-review.googlesource.com/45874Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #20090

Change-Id: I881607e55cd946a703e74a7d8ae2bbde67546510
Reviewed-on: https://go-review.googlesource.com/45816Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: I78443d5874a7667fbac78eac188d402227373da3
Reviewed-on: https://go-review.googlesource.com/45813Reviewed-by: Ian Lance Taylor <iant@golang.org>