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Commit Graph

24154 Commits

Author SHA1 Message Date
Rob Pike
173fa1d809 cmd/go: delete references to old tools (5a etc.) from cmd/go docs
Don't talk about commands that no longer exist.

There are still references throughout the tree, mostly in comments,
but they provide a charming historical backdrop for the idle tourist.

Change-Id: I637ebdce05bbc7df5addcc46cb772d2bb9f3e073
Reviewed-on: https://go-review.googlesource.com/11885
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-07-05 06:25:51 +00:00
Josh Bleecher Snyder
71832ff489 math/rand: improve NewZipf documentation
Change-Id: I78f0f9ac33db153c4a0d7f9866da20ebcd3d3639
Reviewed-on: https://go-review.googlesource.com/11872
Reviewed-by: Rob Pike <r@golang.org>
2015-07-03 21:39:04 +00:00
Nigel Tao
40a1516a09 image/draw: fix double-draw when the dst is paletted.
The second (fallback) draw is a no-op, but it's a non-trivial amount of work.

Fixes #11550.

benchmark               old ns/op     new ns/op     delta
BenchmarkPaletted-4     16301219      7309568       -55.16%

Change-Id: Ic88c537b2b0c710cf517888f3dd15cb702dd142f
Reviewed-on: https://go-review.googlesource.com/11858
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-07-03 03:08:40 +00:00
Rob Pike
09b5463d9b doc: finish the small library changes in go1.5.html; start work on tools
Also add words about the assembler.

Change-Id: I9bd8cc88076f06b0eef36a07f57d1ad5d9261d8d
Reviewed-on: https://go-review.googlesource.com/11853
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-07-02 20:22:51 +00:00
Dmitry Vyukov
11f50f41ee cmd/trace: log errors to console in AJAX handler
Fixes #11508

Change-Id: I72e83893b76f75685d6edfe65ca6691d97539226
Reviewed-on: https://go-review.googlesource.com/11864
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-07-02 19:10:00 +00:00
Mikio Hara
2a0fc9e70e Revert "net, internal/syscall/unix: add SocketConn, SocketPacketConn"
This reverts commit 6f7961da28.

Russ suggests changing the frozon syscall package and obviously it's a
better solution. Perhaps he will also let me know the way how to get the
project owners to agree later.

Fixes #11492.

Change-Id: I98f9f366b72b85db54b4acfc3a604b62fb6d783c
Reviewed-on: https://go-review.googlesource.com/11854
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-07-02 16:11:03 +00:00
Brad Fitzpatrick
85938714e9 mime/multipart: fix bug when body contains prefix of the boundary
Fixes #10616

Change-Id: I4ef25eb0be6ccf474976fdb5087dd2c62c66c510
Reviewed-on: https://go-review.googlesource.com/11811
Reviewed-by: Andrew Gerrand <adg@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
2015-07-02 16:04:34 +00:00
Dmitry Vyukov
1b96091a05 internal/trace: add comment for stable sort
As per comments in cl/11834.

Change-Id: I285536b882fa9496e15d77d0d4c16ee913aca581
Reviewed-on: https://go-review.googlesource.com/11861
Reviewed-by: Daniel Theophanes <kardianos@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-07-02 16:04:07 +00:00
Rob Pike
d16c7f8004 crypto: fix non-sentence in documentation for Decrypter
Comment change only.

Change-Id: I2e32c2b34d5a5659ead6d6082b06e1b039bf1147
Reviewed-on: https://go-review.googlesource.com/11852
Reviewed-by: Russ Cox <rsc@golang.org>
2015-07-02 03:43:34 +00:00
Dmitry Vyukov
64e48bbaba internal/trace: stable sort events
On some VMs two events can happen at the same time. For examples:
179827399 GoStart p=2 g=11 off=936359 g=11
179827399 GoUnblock p=2 g=0 off=936355 g=11
If we do non-stable sort, the events can be reordered making the trace inconsistent.
Do stable sort instead.

Batches are dumped in FIFO order, so if these same-time events are split into
separate batches, stable sort still works.

Events on different CPUs go into different batches and can be reordered.
But the intention is that causally-related events on different CPUs
will have larger (non-zero) time diff.

Update #11320

Change-Id: Id1df96af41dff68ea1782ab4b23d5afd63b890c9
Reviewed-on: https://go-review.googlesource.com/11834
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-07-02 00:37:16 +00:00
Rob Pike
cd2e2f60e7 doc: add most major changes and most net changes to go1.5.html
Change-Id: Ied305480f22b60767c4628e5a31236ac01eafc86
Reviewed-on: https://go-review.googlesource.com/11825
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-07-02 00:10:40 +00:00
Roger Peppe
5ae822ba69 encoding/xml: minor changes
Changes suggested by Nigel Tao in https://go-review.googlesource.com/#/c/11635
after that had been submitted.

Change-Id: I7b28e1c8488c8565399a8017453dc7ff1fd215e8
Reviewed-on: https://go-review.googlesource.com/11832
Reviewed-by: Nigel Tao <nigeltao@golang.org>
2015-07-01 14:13:16 +00:00
Dmitry Vyukov
1cbbd7f545 cmd/trace: fix time scale
Integrate the latest trace-viewer changes.
It now handles nanoseconds without any issues (thanks to @egonelbre!).
So change timestamps from microseconds to nanoseconds.

Change-Id: I010f27effde7e80c9992e6f276f6912354d27df4
Reviewed-on: https://go-review.googlesource.com/11244
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Egon Elbre <egonelbre@gmail.com>
2015-07-01 10:37:10 +00:00
Rob Pike
6fe9c4a7bd doc: more library in go1.5.html
Everything in the library but crypto and net.

Change-Id: I89b21b9621e6d338fa1891da0eabba5d7d2fe349
Reviewed-on: https://go-review.googlesource.com/11820
Reviewed-by: Russ Cox <rsc@golang.org>
2015-07-01 02:25:39 +00:00
Brad Fitzpatrick
fc2eee87ed database/sql: make Register safe for concurrent use
Adding a mutex was easier than documenting it, and is consistent with
gob.

Fixes #9847

Change-Id: Ifa94c17e7c11643add81b35431ef840b794d78b1
Reviewed-on: https://go-review.googlesource.com/11682
Reviewed-by: Andrew Gerrand <adg@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-06-30 23:15:03 +00:00
Brad Fitzpatrick
300d9a2158 net/http: harden Server against request smuggling
See RFC 7230.

Thanks to Régis Leroy for the report.

Change-Id: Ic1779bc2180900430d4d7a4938cac04ed73c304c
Reviewed-on: https://go-review.googlesource.com/11810
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
2015-06-30 22:56:30 +00:00
Brad Fitzpatrick
2714005a24 internal/singleflight: deflake test
Fixes #11475

Change-Id: Ibaedbb732bb1b9f062bd5af7b866ec4758c724a7
Reviewed-on: https://go-review.googlesource.com/11770
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
2015-06-30 22:55:59 +00:00
Alan Donovan
f11109fbc9 go/types: change {Type,Object,Selection}String to accept a Qualifier function
The optional Qualifier function determines what prefix to attach to
package-level names, enabling clients to qualify packages in different
ways, for example, using only the package name instead of its complete
path, or using the locally appropriate name for package given a set of
(possibly renaming) imports.

Prior to this change, clients wanting this behavior had to copy
hundreds of lines of complex printing logic.

Fun fact: (*types.Package).Path and (*types.Package).Name are valid
Qualifier functions.

We provide the RelativeTo helper function to create Qualifiers so that
the old behavior remains a one-liner.

Fixes golang/go#11133

This CL is a copy of https://go-review.googlesource.com/#/c/11692/
to the golang.org/x/tools repository.

Change-Id: I26d0f3644d077a26bfe350989f9c545f018eefbf
Reviewed-on: https://go-review.googlesource.com/11790
Reviewed-by: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
2015-06-30 21:44:42 +00:00
Russ Cox
6f80e5edf4 cmd/link: reject data size > 2 GB
We can't address more than this on amd64 anyway.

Fixes #9862.

Change-Id: Ifb1abae558e2e1ee2dc953a76995f3f08c60b1df
Reviewed-on: https://go-review.googlesource.com/11715
Reviewed-by: Austin Clements <austin@google.com>
2015-06-30 19:40:39 +00:00
Russ Cox
e8f2eb4349 cmd/compile: allow linker to drop string headers when not needed
Compiling a simple file containing a slice of 100,000 strings,
the size of the resulting binary dropped from 5,896,224 bytes
to 3,495,968 bytes, which is the expected 2,400,000 bytes,
give or take.

Fixes #7384.

Change-Id: I3e551b5a1395b523a41b33518d81a1bf28da0906
Reviewed-on: https://go-review.googlesource.com/11698
Reviewed-by: Austin Clements <austin@google.com>
2015-06-30 19:27:52 +00:00
Russ Cox
3b6e86f48a cmd/compile: fix race detector handling of OBLOCK nodes
Fixes #7561 correctly.
Fixes #9137.

Change-Id: I7f27e199d7101b785a7645f789e8fe41a405a86f
Reviewed-on: https://go-review.googlesource.com/11713
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
2015-06-30 19:25:18 +00:00
Brad Fitzpatrick
117ddcb83d net/textproto: don't treat spaces as hyphens in header keys
This was originally done in https://codereview.appspot.com/5690059
(Feb 2012) to deal with bad response headers coming back from webcams,
but it presents a potential security problem with HTTP request
smuggling for request headers containing "Content Length" instead of
"Content-Length".

Part of overall HTTP hardening for request smuggling. See RFC 7230.

Thanks to Régis Leroy for the report.

Change-Id: I92b17fb637c9171c5774ea1437979ae2c17ca88a
Reviewed-on: https://go-review.googlesource.com/11772
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-06-30 17:59:02 +00:00
Dmitry Vyukov
8884fa7476 cmd/trace: sort procs
If you have more than 10 procs, then currently they are sorted alphabetically as
0, 10, 11, ..., 19, 2, 20, ...
Assign explicit order to procs so that they are sorted numerically.

Change-Id: I6d978d2cd439aa2fcbcf147842a643f9073eef75
Reviewed-on: https://go-review.googlesource.com/11750
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
2015-06-30 16:50:57 +00:00
Brad Fitzpatrick
9462bcedc6 net/http: harden, document func SetCookie and type Cookie
Fixes #9758

Change-Id: I3089ec06cddd74b547d8b10834d7478a04b02069
Reviewed-on: https://go-review.googlesource.com/11701
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-06-30 16:19:02 +00:00
Russ Cox
8e6dc76e1f net/url: only record RawPath when it is needed
RawPath is a hint to the desired encoding of Path.
It is ignored when it is not a valid encoding of Path,
such as when Path has been changed but RawPath has not.
It is not ignored but also not useful when it matches
the url package's natural choice of encoding.
In this latter case, set it to the empty string.
This should help drive home the point that clients
cannot in general depend on it being present and
that they should use the EncodedPath method instead.

This also reduces the impact of the change on tests,
especially tests that use reflect.DeepEqual on parsed URLs.

Change-Id: I437c51a33b85439a31c307caf1436118508ea196
Reviewed-on: https://go-review.googlesource.com/11760
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-06-30 15:54:27 +00:00
Dmitry Vyukov
19b8aa3b5d cmd/compile/internal/gc: give OASWB name
Change-Id: Iacb84421215ca80c7add2818118b2af1a650fd58
Reviewed-on: https://go-review.googlesource.com/11639
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-06-30 15:51:59 +00:00
Roger Peppe
bb7e665687 encoding/xml: fix xmlns= behavior
When an xmlns="..." attribute was explicitly generated,
it was being ignored because the name space on the
attribute was assumed to have been explicitly set (to the empty
name space) and it's not possible to have an element in the
empty name space when there is a non-empty name space set.

We fix this by recording when a default name space has been
explicitly set and setting the name space of the element to that
so printer.defineNS can do its work correctly.

We do not attempt to add our own xmlns="..." attribute
when one is explicitly set.

We also add tests for EncodeElement, as that's the only way
to attain coverage of some of the changed behaviour.
Some other test coverage is also increased, although
more work remains to be done in this area.

This change was jointly developed with Martin Hilton (mhilton on github).

Fixes #11431.

Change-Id: I7b85e06eea5b18b2c15ec16dcbd92a8e1d6a9a4e
Reviewed-on: https://go-review.googlesource.com/11635
Reviewed-by: Russ Cox <rsc@golang.org>
2015-06-30 07:42:37 +00:00
Andrew Gerrand
ab9c25f2de cmd/go: use GOOS and GOARCH from build context for "go generate"
Fixes #11438

Change-Id: Iedd31918aa5187fc3fdaed71c8dad82075559084
Reviewed-on: https://go-review.googlesource.com/11667
Reviewed-by: Rob Pike <r@golang.org>
2015-06-30 06:52:47 +00:00
Nigel Tao
b8d2d6b9c0 image/gif: accept LZW encodings that do not have an explicit end marker.
The spec says this is invalid, but it matches giflib's behavior.

Fixes #9856 (together with https://go-review.googlesource.com/11661).

Change-Id: I05701f62a9e5e724a2d85c6b87ae4111e537146b
Reviewed-on: https://go-review.googlesource.com/11663
Reviewed-by: Rob Pike <r@golang.org>
2015-06-30 03:47:51 +00:00
Nigel Tao
fea18f5a34 compress/lzw: return the partial decoding for a truncated input.
This is needed by issue #9856.

Change-Id: Idad570a7e55ad903aab55372d390bc746c4e19cf
Reviewed-on: https://go-review.googlesource.com/11661
Reviewed-by: Rob Pike <r@golang.org>
2015-06-30 03:47:06 +00:00
Alex Brainman
53eb4783c2 archive/tar: move round-trip reading into common os file
Fixes #11426

Change-Id: I77368b0e852149ed4533e139cc43887508ac7f78
Reviewed-on: https://go-review.googlesource.com/11662
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Russ Cox <rsc@golang.org>
2015-06-30 02:20:20 +00:00
Aaron Jacobs
8b4278ffb7 net/http: add a Request.Cancel channel.
This allows for "race free" cancellation, in the sense discussed in
issue #11013: in contrast to Transport.CancelRequest, the cancellation
will not be lost if the user cancels before the request is put into the
transport's internal map.

Fixes #11013.

Change-Id: I0b5e7181231bdd65d900e343f764b4d1d7c422cd
Reviewed-on: https://go-review.googlesource.com/11601
Run-TryBot: David Symonds <dsymonds@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-06-30 01:24:15 +00:00
Russ Cox
1122836b5f cmd/compile: reject large floating point exponents without math/big
For #11326 (but not a fix).

Change-Id: Ic51814f5cd7357427c3fd990a5522775d05e7987
Reviewed-on: https://go-review.googlesource.com/11673
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-06-29 21:18:01 +00:00
Russ Cox
643ef15b16 io: tweak Reader comment
I think this has the same meaning as before,
but the text is tighter, and it makes some people happy.

Fixes #10182.

Change-Id: I7ee1eae4bcd6ee4a5898ea948648939e6bde5f01
Reviewed-on: https://go-review.googlesource.com/11674
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
2015-06-29 21:17:47 +00:00
Russ Cox
4df6b1ec2f path/filepath: document and test behavior of SkipDir on files
This behavior is not what we might have designed from the start,
but it has been present since Go 1. Rather than make a visible
behavioral change that might cause programs to work differently
in Go ≤1.4 vs Go ≥1.5, document what SkipDir on a non-directory
has always meant. If code doesn't want this meaning, it is easy
enough not to return SkipDir on non-directories.

Fixes #10533.

Change-Id: Ic0612f032044bc7c69bf62583a02037e4b47530b
Reviewed-on: https://go-review.googlesource.com/11690
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
2015-06-29 21:16:35 +00:00
Russ Cox
69f0d4c6be cmd/link: detect -X setting non-string variable
Fixes #9621.

Change-Id: Ib9c6001378364af899f57fd4b89fb23af2042923
Reviewed-on: https://go-review.googlesource.com/11694
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
2015-06-29 20:28:36 +00:00
Rob Pike
c418fe734a doc: finish listing the non-crypto non-net small API changes
Change-Id: I5791639e71874ce13fac836a0c6014e20ee7417e
Reviewed-on: https://go-review.googlesource.com/11664
Reviewed-by: Russ Cox <rsc@golang.org>
2015-06-29 20:27:42 +00:00
Alan Donovan
c77809e903 go/types: go/types: add an API test of the Scope type
Also: make (*Scope).Innermost work for Package scopes.

This change is identical to http://go-review.googlesource.com/#/c/11691/,
except for minor changes required by the use of testImporter.

Change-Id: Id07e66f78987f7242c2e642dfd6ee613676e10e5
Reviewed-on: https://go-review.googlesource.com/11714
Reviewed-by: Robert Griesemer <gri@golang.org>
2015-06-29 20:16:18 +00:00
Russ Cox
34846aef78 cmd/link: fix -s with external linking
This code used to only be run for ELF, with the predictable
result that using -s with external linking broke on Windows and OS X.
Moving it here should fix Windows and does fix OS X.

CL 10835 also claims to fix the crash on Windows.
I don't know whether it does so correctly, but regardless,
this CL should make that one a no-op.

Fixes #10254.

Change-Id: I2e7b45ab0c28568ddbb1b50581dcc157ae0e7ffe
Reviewed-on: https://go-review.googlesource.com/11695
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2015-06-29 19:49:38 +00:00
Russ Cox
27edd7209e cmd/compile: enable PAUTO capture variables on arch != 6
Fixes #9865.

Change-Id: I8ce5b1708ed938910c59899706e470271c2e7e9d
Reviewed-on: https://go-review.googlesource.com/11699
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-06-29 19:49:18 +00:00
Adam Langley
2814906df0 crypto/rsa: check for primes ≤ 1 in Validate
Change 7c7126cfeb removed the primality
checking in Validate to save CPU time. That check happened to be
filtering out private keys with primes that were zero or one. Without
that filtering, such primes cause a panic when trying to use such a
private key.

This change specifically checks for and rejects primes ≤ 1 in Validate.

Fixes #11233.

Change-Id: Ie6537edb8250c07a45aaf50dab43227002ee7386
Reviewed-on: https://go-review.googlesource.com/11611
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
2015-06-29 19:32:48 +00:00
Brad Fitzpatrick
9b2d84efc8 net/http/httptest: increase test Server's key size
Fixes #10725

Change-Id: Ic8685dc238a0ffc95fafb512a8587d2eb5fe9d5f
Reviewed-on: https://go-review.googlesource.com/11720
Reviewed-by: Adam Langley <agl@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-06-29 19:30:48 +00:00
Tom Heng
162d2c1608 cmd/go: 'go env' print GO15VENDOREXPERIMENT in Go1.5
Fixes #11410

Change-Id: I9d01be3e01f74f4b12a516aba8a5d20d9b277ec6
Reviewed-on: https://go-review.googlesource.com/11539
Reviewed-by: Russ Cox <rsc@golang.org>
2015-06-29 19:29:01 +00:00
Brad Fitzpatrick
7749a9ab56 sync: disable flaky WaitGroup misuse test in short mode
Update #11443

Change-Id: Icb7ea291a837dcf2799a791a2ba780fd2a5e712b
Reviewed-on: https://go-review.googlesource.com/11721
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
2015-06-29 18:44:52 +00:00
Russ Cox
5267bf075b cmd/go: disable TestIssue10952 without external network
Should fix arm64 build failure.

Change-Id: Ib35e4a69a1082e461a1eddf3265544a1d2ff98e5
Reviewed-on: https://go-review.googlesource.com/11710
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2015-06-29 18:00:07 +00:00
Russ Cox
55203c7dd5 cmd/compile: allow unnamed constants to set line number
Fixes #8836.

Change-Id: Idda9f4a987e03b3bdf5e8fdb984fe56d6f84aa59
Reviewed-on: https://go-review.googlesource.com/11672
Reviewed-by: David Chase <drchase@google.com>
2015-06-29 17:35:55 +00:00
Russ Cox
8b99bb7b8c runtime: fix broken arm builds
Change-Id: I08de33aacb3fc932722286d69b1dd70ffe787c89
Reviewed-on: https://go-review.googlesource.com/11697
Reviewed-by: Russ Cox <rsc@golang.org>
2015-06-29 17:33:23 +00:00
Russ Cox
434e0bc0a0 cmd/link: record missing pcdata tables correctly
The old code was recording the current table output offset,
so the table from the next function would be used instead of
the runtime realizing that there was no table at all.

Add debug constant in runtime to check this for every function
at startup. It's too expensive to do that by default, but we can
do the last five functions. The end of the table is usually where
the C symbols end up, so that's where the problems typically are.

Fixes #10747.
Fixes #11396.

Change-Id: I13592e78017969fc22979fa902e19e1b151d41b1
Reviewed-on: https://go-review.googlesource.com/11657
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
2015-06-29 16:07:14 +00:00
Austin Clements
1b917484a8 runtime: reset mark state before checkmark and gctrace=2 mark
Currently we fail to reset the live heap accounting state before the
checkmark mark and before the gctrace=2 extra mark. As a result, if
either are enabled, at the end of GC it thinks there are 0 bytes of
live heap, which causes the GC controller to initiate a new GC
immediately, regardless of the true heap size.

Fix this by factoring this state reset into a function and calling it
before all three possible marks.

This function should be merged with gcResetGState, but doing so
requires some additional cleanup, so it will wait for after the
freeze. Filed #11427 for this cleanup.

Fixes #10492.

Change-Id: Ibe46348916fc8368fac6f086e142815c970a6f4d
Reviewed-on: https://go-review.googlesource.com/11561
Reviewed-by: Russ Cox <rsc@golang.org>
2015-06-29 15:58:29 +00:00
Austin Clements
d57056ba26 runtime: don't free stack spans during GC
Memory for stacks is manually managed by the runtime and, currently
(with one exception) we free stack spans immediately when the last
stack on a span is freed. However, the garbage collector assumes that
spans can never transition from non-free to free during scan or mark.
This disagreement makes it possible for the garbage collector to mark
uninitialized objects and is blocking us from re-enabling the bad
pointer test in the garbage collector (issue #9880).

For example, the following sequence will result in marking an
uninitialized object:

1. scanobject loads a pointer slot out of the object it's scanning.
   This happens to be one of the special pointers from the heap into a
   stack. Call the pointer p and suppose it points into X's stack.

2. X, running on another thread, grows its stack and frees its old
   stack.

3. The old stack happens to be large or was the last stack in its
   span, so X frees this span, setting it to state _MSpanFree.

4. The span gets reused as a heap span.

5. scanobject calls heapBitsForObject, which loads the span containing
   p, which is now in state _MSpanInUse, but doesn't necessarily have
   an object at p. The not-object at p gets marked, and at this point
   all sorts of things can go wrong.

We already have a partial solution to this. When shrinking a stack, we
put the old stack on a queue to be freed at the end of garbage
collection. This was done to address exactly this problem, but wasn't
a complete solution.

This commit generalizes this solution to both shrinking and growing
stacks. For stacks that fit in the stack pool, we simply don't free
the span, even if its reference count reaches zero. It's fine to reuse
the span for other stacks, and this enables that. At the end of GC, we
sweep for cached stack spans with a zero reference count and free
them. For larger stacks, we simply queue the stack span to be freed at
the end of GC. Ideally, we would reuse these large stack spans the way
we can small stack spans, but that's a more invasive change that will
have to wait until after the freeze.

Fixes #11267.

Change-Id: Ib7f2c5da4845cc0268e8dc098b08465116972a71
Reviewed-on: https://go-review.googlesource.com/11502
Reviewed-by: Russ Cox <rsc@golang.org>
2015-06-29 15:33:40 +00:00