Some libraries, for example, OpenBLAS, create work threads in a global constructor.
If we're doing cpu profiling, it's possible that SIGPROF might come to some of the
worker threads before we make our first cgo call. Cgocallback used to terminate the
process when that happens, but it's better to miss a couple profiling signals than
to abort in this case.
Fixes#9456.
Change-Id: I112b8e1a6e10e6cc8ac695a4b518c0f577309b6b
Reviewed-on: https://go-review.googlesource.com/2141
Reviewed-by: Ian Lance Taylor <iant@golang.org>
(cherry picked from commit 5da9c8cd0a)
Reviewed-on: https://go-review.googlesource.com/2789
Reviewed-by: Andrew Gerrand <adg@golang.org>
This incorporates the various git-related updates that have
happened since the Go 1.4 release. Since Go 1.4.1 will be issued
from Git, it is appropriate to replace the Mercurial instructions
with Git instructions.
Change-Id: Idec041002c7f325c4eee6f25c50423b088b11468
Reviewed-on: https://go-review.googlesource.com/2788
Reviewed-by: Andrew Gerrand <adg@golang.org>
Also: checkout sub-repos from Mercurial manually
instead of using "go get". (for the 1.4 release)
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/190720043
I read through and vetted these but others should look too.
LGTM=bradfitz, adg
R=r, minux, bradfitz, adg
CC=adg, golang-codereviews, gri, iant
https://golang.org/cl/182560043
These are the references that affect current Go users.
I left intact references in older release notes;
we can figure out what to do with them later.
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/186140043
««« CL 182580043 / 2d1ab17a670a
encoding/xml: remove SyntaxError.Byte
It is unused. It was introduced in the CL that added InputOffset.
I suspect it was an editing mistake.
LGTM=bradfitz
R=bradfitz
CC=golang-codereviews
https://golang.org/cl/182580043
»»»
TBR=bradfitz
CC=golang-codereviews
https://golang.org/cl/180630043
We forgot to do the usual API review.
Make that not possible in the future.
I'll pull this change over to the main
branch too, but it's more important
(and only testable) here.
LGTM=bradfitz
R=bradfitz
CC=golang-codereviews
https://golang.org/cl/185050043
(That is, changes can originate in the branch.
The main branch has diverged enough that this
may be necessary.)
LGTM=bradfitz
R=adg, bradfitz
CC=golang-codereviews
https://golang.org/cl/187810043
««« CL 182480043 / 8d42099cdc23
cmd/go: fix build
The new semantics of split require the newline be present.
The test was stale.
LGTM=adg
R=golang-codereviews, adg
CC=golang-codereviews
https://golang.org/cl/182480043
»»»
TBR=r
CC=golang-codereviews
https://golang.org/cl/178690043
««« CL 182970043 / 573a7b5178c4
cmd/go: avoid use of bufio.Scanner in generate
Scanner can't handle stupid long lines and there are
reports of stupid long lines in production.
Note the issue isn't long "//go:generate" lines, but
any long line in any Go source file.
To be fair, if you're going to have a stupid long line
it's not a bad bet you'll want to run it through go
generate, because it's some embeddable asset that
has been machine generated. (One could ask why
that generation process didn't add a newline or two,
but we should cope anyway.)
Rewrite the file scanner in "go generate" so it can
handle arbitrarily long lines, and only stores in memory
those lines that start "//go:generate".
Also: Adjust the documentation to make clear that it
does not parse the file.
Fixes#9143.
Fixes#9196.
LGTM=rsc, dominik.honnef
R=rsc, cespare, minux, dominik.honnef
CC=golang-codereviews
https://golang.org/cl/182970043
»»»
TBR=r
CC=golang-codereviews
https://golang.org/cl/183060044
««« CL 180380043 / d56c648b069f
cmd/pprof/internal/commands: add command to open browser on windows
While we're at there, also add a message to prompt the user to install
Graphviz if "dot" command is not found.
Fixes#9178.
LGTM=adg, alex.brainman, cookieo9, rsc
R=rsc, adg, bradfitz, alex.brainman, cookieo9, smyrman
CC=golang-codereviews
https://golang.org/cl/180380043
»»»
TBR=minux
CC=golang-codereviews
https://golang.org/cl/186760043
««« CL 179680043 / 752cd9199639
runtime: fix hang in GC due to shrinkstack vs netpoll race
During garbage collection, after scanning a stack, we think about
shrinking it to reclaim some memory. The shrinking code (called
while the world is stopped) checked that the status was Gwaiting
or Grunnable and then changed the state to Gcopystack, to essentially
lock the stack so that no other GC thread is scanning it.
The same locking happens for stack growth (and is more necessary there).
oldstatus = runtime·readgstatus(gp);
oldstatus &= ~Gscan;
if(oldstatus == Gwaiting || oldstatus == Grunnable)
runtime·casgstatus(gp, oldstatus, Gcopystack); // oldstatus is Gwaiting or Grunnable
else
runtime·throw("copystack: bad status, not Gwaiting or Grunnable");
Unfortunately, "stop the world" doesn't stop everything. It stops all
normal goroutine execution, but the network polling thread is still
blocked in epoll and may wake up. If it does, and it chooses a goroutine
to mark runnable, and that goroutine is the one whose stack is shrinking,
then it can happen that between readgstatus and casgstatus, the status
changes from Gwaiting to Grunnable.
casgstatus assumes that if the status is not what is expected, it is a
transient change (like from Gwaiting to Gscanwaiting and back, or like
from Gwaiting to Gcopystack and back), and it loops until the status
has been restored to the expected value. In this case, the status has
changed semi-permanently from Gwaiting to Grunnable - it won't
change again until the GC is done and the world can continue, but the
GC is waiting for the status to change back. This wedges the program.
To fix, call a special variant of casgstatus that accepts either Gwaiting
or Grunnable as valid statuses.
Without the fix bug with the extra check+throw in casgstatus, the
program below dies in a few seconds (2-10) with GOMAXPROCS=8
on a 2012 Retina MacBook Pro. With the fix, it runs for minutes
and minutes.
package main
import (
"io"
"log"
"net"
"runtime"
)
func main() {
const N = 100
for i := 0; i < N; i++ {
l, err := net.Listen("tcp", "127.0.0.1:0")
if err != nil {
log.Fatal(err)
}
ch := make(chan net.Conn, 1)
go func() {
var err error
c1, err := net.Dial("tcp", l.Addr().String())
if err != nil {
log.Fatal(err)
}
ch <- c1
}()
c2, err := l.Accept()
if err != nil {
log.Fatal(err)
}
c1 := <-ch
l.Close()
go netguy(c1, c2)
go netguy(c2, c1)
c1.Write(make([]byte, 100))
}
for {
runtime.GC()
}
}
func netguy(r, w net.Conn) {
buf := make([]byte, 100)
for {
bigstack(1000)
_, err := io.ReadFull(r, buf)
if err != nil {
log.Fatal(err)
}
w.Write(buf)
}
}
var g int
func bigstack(n int) {
var buf [100]byte
if n > 0 {
bigstack(n - 1)
}
g = int(buf[0]) + int(buf[99])
}
Fixes#9186.
LGTM=rlh
R=austin, rlh
CC=dvyukov, golang-codereviews, iant, khr, r
https://golang.org/cl/179680043
»»»
TBR=rlh
CC=golang-codereviews
https://golang.org/cl/184030043
««« CL 179030043 / e4ab8f908aac
runtime: fix atomic operations on non-heap addresses
Race detector runtime does not tolerate operations on addresses
that was not previously declared with __tsan_map_shadow
(namely, data, bss and heap). The corresponding address
checks for atomic operations were removed in
https://golang.org/cl/111310044
Restore these checks.
It's tricker than just not calling into race runtime,
because it is the race runtime that makes the atomic
operations themselves (if we do not call into race runtime
we skip the atomic operation itself as well). So instead we call
__tsan_go_ignore_sync_start/end around the atomic operation.
This forces race runtime to skip all other processing
except than doing the atomic operation itself.
Fixes#9136.
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/179030043
»»»
TBR=dvyukov
CC=golang-codereviews
https://golang.org/cl/180030043
««« CL 176070043 / 500cb52e08e6
build: disable race external linking test on OS X 10.6 and earlier
External linking doesn't work there at all.
LGTM=bradfitz
R=adg, bradfitz
CC=golang-codereviews
https://golang.org/cl/176070043
»»»
LGTM=bradfitz, adg
R=adg, bradfitz
CC=golang-codereviews
https://golang.org/cl/175400043
««« CL 179980043 / d71cc7e8a0e0
runtime: remove assumption that noptrdata data bss noptrbss are ordered and contiguous
The assumption can be violated by external linkers reordering them or
inserting non-Go sections in between them. I looked briefly at trying
to write out the _go_.o in external linking mode in a way that forced
the ordering, but no matter what there's no way to force Go's data
and Go's bss to be next to each other. If there is any data or bss from
non-Go objects, it's very likely to get stuck in between them.
Instead, rewrite the two places we know about that make the assumption.
I grepped for noptrdata to look for more and didn't find any.
The added race test (os/exec in external linking mode) fails without
the changes in the runtime. It crashes with an invalid pointer dereference.
Fixes#9133.
LGTM=dneil
R=dneil
CC=dvyukov, golang-codereviews, iant
https://golang.org/cl/179980043
»»»
LGTM=dneil
R=dneil
CC=golang-codereviews
https://golang.org/cl/173510043
««« CL 174450043 / 699cc091a16d
undo CL 131750044 / 2d6d44ceb80e
Breaks reading from stdin in parent after exec with SysProcAttr{Setpgid: true}.
package main
import (
"fmt"
"os"
"os/exec"
"syscall"
)
func main() {
cmd := exec.Command("true")
cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
cmd.Run()
fmt.Printf("Hit enter:")
os.Stdin.Read(make([]byte, 100))
fmt.Printf("Bye\n")
}
In go1.3, I type enter at the prompt and the program exits.
With the CL being rolled back, the program wedges at the
prompt.
««« original CL description
syscall: SysProcAttr job control changes
Making the child's process group the foreground process group and
placing the child in a specific process group involves co-ordination
between the parent and child that must be done post-fork but pre-exec.
LGTM=iant
R=golang-codereviews, gobot, iant, mikioh.mikioh
CC=golang-codereviews
https://golang.org/cl/131750044
»»»
LGTM=minux, dneil
R=dneil, minux
CC=golang-codereviews, iant, michael.p.macinnis
https://golang.org/cl/174450043
»»»
LGTM=minux
R=dneil, minux
CC=golang-codereviews
https://golang.org/cl/179970043
««« CL 178910043 / 3916b070c5f3
doc/go1.4.html: rewrite first sentence to make it clearer
The grammar was atrocious, probably the victim of an editing error.
LGTM=bradfitz
R=bradfitz
CC=golang-codereviews
https://golang.org/cl/178910043
»»»
LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/175310043
««« CL 174250043 / c16349455e05
debug/goobj: move to cmd/internal/goobj
debug/goobj is not ready to be published but it is
needed for the various binary-reading commands.
Move to cmd/internal/goobj.
(The Go 1.3 release branch deleted it, but that's not
an option anymore due to the command dependencies.
The API is still not vetted nor terribly well designed.)
LGTM=adg, dsymonds
R=adg, dsymonds
CC=golang-codereviews
https://golang.org/cl/174250043
»»»
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/177890043
The SudoG used to sit on the stack, so it was cheap to allocated
and didn't need to be cleaned up when finished.
For the conversion to Go, we had to move sudog off the stack
for a few reasons, so we added a cache of recently used sudogs
to keep allocation cheap. But we didn't add any of the necessary
cleanup before adding a SudoG to the new cache, and so the cached
SudoGs had stale pointers inside them that have caused all sorts
of awful, hard to debug problems.
CL 155760043 made sure SudoG.elem is cleaned up.
CL 150520043 made sure SudoG.selectdone is cleaned up.
This CL makes sure SudoG.next, SudoG.prev, and SudoG.waitlink
are cleaned up. I should have done this when I did the other two
fields; instead I wasted a week tracking down a leak they caused.
A dangling SudoG.waitlink can point into a sudogcache list that
has been "forgotten" in order to let the GC collect it, but that
dangling .waitlink keeps the list from being collected.
And then the list holding the SudoG with the dangling waitlink
can find itself in the same situation, and so on. We end up
with lists of lists of unusable SudoGs that are still linked into
the object graph and never collected (given the right mix of
non-trivial selects and non-channel synchronization).
More details in golang.org/issue/9110.
Fixes#9110.
LGTM=r
R=r
CC=dvyukov, golang-codereviews, iant, khr
https://golang.org/cl/177870043
I just created that redirect, so we can change
it once the wiki moves.
LGTM=bradfitz, khr
R=khr, bradfitz
CC=golang-codereviews
https://golang.org/cl/177780043
Per private thread soliciting help. I realized part of this is
documented in several places, but we lacked a unifying
example.
LGTM=rsc
R=golang-codereviews
CC=adg, golang-codereviews, iant, rsc
https://golang.org/cl/171620043
Language clarification.
The existing rules for selector expressions imply
automatic dereferencing of pointers to struct fields.
They also implied automatic dereferencing of selectors
denoting methods. In almost all cases, such automatic
dereferencing does indeed take place for methods but the
reason is not the selector rules but the fact that method
sets include both methods with T and *T receivers; so for
a *T actual receiver, a method expecting a formal T
receiver, also accepts a *T (and the invocation or method
value expression is the reason for the auto-derefering).
However, the rules as stated so far implied that even in
case of a variable p of named pointer type P, a selector
expression p.f would always be shorthand for (*p).f. This
is true for field selectors f, but cannot be true for
method selectors since a named pointer type always has an
empty method set.
Named pointer types may never appear as anonymous field
types (and method receivers, for that matter), so this
only applies to variables declared of a named pointer
type. This is exceedingly rare and perhaps shouldn't be
permitted in the first place (but we cannot change that).
Amended the selector rules to make auto-deref of values
of named pointer types an exception to the general rules
and added corresponding examples with explanations.
Both gc and gccgo have a bug where they do auto-deref
pointers of named types in method selectors where they
should not:
See http://play.golang.org/p/c6VhjcIVdM , line 45.
Fixes#5769.
Fixes#8989.
LGTM=r, rsc
R=r, rsc, iant, ken
CC=golang-codereviews
https://golang.org/cl/168790043
Shenghou Ma
Russ Cox
David Symonds
Andrew Gerrand
Nigel Tao
Yasuhiro Matsumoto
Brad Fitzpatrick
Emil Hessman
Robin Eklind
Robert Griesemer
Rob Pike