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Austin Clements 3f22adecc7 runtime: fix sigprof stack barrier locking `f90b48e` intended to require the stack barrier lock in all cases of sigprof that walked the user stack, but got it wrong. In particular, if sp < gp.stack.lo \|\| gp.stack.hi < sp, tracebackUser would be true, but we wouldn't acquire the stack lock. If it then turned out that we were in a cgo call, it would walk the stack without the lock. In fact, the whole structure of stack locking is sigprof is somewhat wrong because it assumes the G to lock is gp.m.curg, but all three gentraceback calls start from potentially different Gs. To fix this, we lower the gcTryLockStackBarriers calls much closer to the gentraceback calls. There are now three separate trylock calls, each clearly associated with a gentraceback and the locked G clearly matches the G from which the gentraceback starts. This actually brings the sigprof logic closer to what it originally was before stack barrier locking. This depends on "runtime: increase assumed stack size in externalthreadhandler" because it very slightly increases the stack used by sigprof; without this other commit, this is enough to blow the profiler thread's assumed stack size. Fixes #12528 (hopefully for real this time!). For the 1.5 branch, though it will require some backporting. On the 1.5 branch, this will not require the "runtime: increase assumed stack size in externalthreadhandler" commit: there's no pcvalue cache, so the used stack is smaller. Change-Id: Id2f6446ac276848f6fc158bee550cccd03186b83 Reviewed-on: https://go-review.googlesource.com/18328 Run-TryBot: Austin Clements <austin@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Russ Cox <rsc@golang.org>		2016-01-07 19:40:38 +00:00
api	api/go1.6.txt: add debug.SetTraceback, build.Package.InvalidGoFiles	2015-12-29 15:20:51 +00:00
doc	doc: mention that Go no longer calls timeBeginPeriod(1) on Windows	2016-01-07 04:16:14 +00:00
lib/time	lib/time: update to IANA release 2015e.	2015-07-22 02:56:31 +00:00
misc	misc/cgo/testcarchive,testcshared: deflake tests	2016-01-07 01:32:29 +00:00
src	runtime: fix sigprof stack barrier locking	2016-01-07 19:40:38 +00:00
test	test/bench/shootout: delete	2016-01-06 17:58:27 +00:00
.gitattributes	.gitattributes: prevent all magic line ending changes	2014-12-12 23:14:54 +00:00
.gitignore	runtime: break out system-specific constants into package sys	2015-11-12 17:04:45 +00:00
AUTHORS	A+C: automated update	2016-01-05 23:26:54 +00:00
CONTRIBUTING.md	doc: suggest security@golang.org for reporting security issues	2015-06-26 09:53:36 +00:00
CONTRIBUTORS	A+C: automated update	2016-01-05 23:26:54 +00:00
LICENSE	…
PATENTS	…
README.md	readme: emphasize issue tracker is for bugs/proposals	2015-10-02 18:44:14 +00:00
favicon.ico	…
robots.txt	…

README.md

The Go Programming Language

Go is an open source programming language that makes it easy to build simple, reliable, and efficient software.

For documentation about how to install and use Go, visit https://golang.org/ or load doc/install-source.html in your web browser.

Our canonical Git repository is located at https://go.googlesource.com/go. There is a mirror of the repository at https://github.com/golang/go.

Go is the work of hundreds of contributors. We appreciate your help!

To contribute, please read the contribution guidelines: https://golang.org/doc/contribute.html

Note that we do not accept pull requests and that we use the issue tracker for bug reports and proposals only. Please ask questions on https://forum.golangbridge.org or https://groups.google.com/forum/#!forum/golang-nuts.

Unless otherwise noted, the Go source files are distributed under the BSD-style license found in the LICENSE file.

Binary Distribution Notes

If you have just untarred a binary Go distribution, you need to set the environment variable $GOROOT to the full path of the go directory (the one containing this file). You can omit the variable if you unpack it into /usr/local/go, or if you rebuild from sources by running all.bash (see doc/install-source.html). You should also add the Go binary directory $GOROOT/bin to your shell's path.

For example, if you extracted the tar file into $HOME/go, you might put the following in your .profile:

export GOROOT=$HOME/go
export PATH=$PATH:$GOROOT/bin

See https://golang.org/doc/install or doc/install.html for more details.