| commit | 70fd4e47d73b92fe90e44ac785e2f98f9df0ab67 | [log] [tgz] |
|---|---|---|
| author | Ian Lance Taylor <iant@golang.org> | Wed Jul 28 21:09:31 2021 -0700 |
| committer | Ian Lance Taylor <iant@golang.org> | Thu Jul 29 15:30:38 2021 +0000 |
| tree | b3e27a617fa1b6d191dac8a40c99142b96f1eb50 | |
| parent | 9eee0ed4391942c73157c868a9ddcfdef48982f9 [diff] |
runtime: avoid possible preemption when returning from Go to C When returning from Go to C, it was possible for the goroutine to be preempted after calling unlockOSThread. This could happen when there a context function installed by SetCgoTraceback set a non-zero context, leading to a defer call in cgocallbackg1. The defer function wrapper, introduced in 1.17 as part of the regabi support, was not nosplit, and hence was a potential preemption point. If it did get preempted, the G would move to a new M. It would then attempt to return to C code on a different stack, typically leading to a SIGSEGV. Fix this in a simple way by postponing the unlockOSThread until after the other defer. Also check for the failure condition and fail early, rather than waiting for a SIGSEGV. Without the fix to cgocall.go, the test case fails about 50% of the time on my laptop. Fixes #47441 Change-Id: Ib8ca13215bd36cddc2a49e86698824a29c6a68ba Reviewed-on: https://go-review.googlesource.com/c/go/+/338197 Trust: Ian Lance Taylor <iant@golang.org> Reviewed-by: Keith Randall <khr@golang.org> Reviewed-by: Cherry Mui <cherryyz@google.com>
Go is an open source programming language that makes it easy to build simple, reliable, and efficient software.
Gopher image by Renee French, licensed under Creative Commons 3.0 Attributions license.
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.
Unless otherwise noted, the Go source files are distributed under the BSD-style license found in the LICENSE file.
Official binary distributions are available at https://golang.org/dl/.
After downloading a binary release, visit https://golang.org/doc/install for installation instructions.
If a binary distribution is not available for your combination of operating system and architecture, visit https://golang.org/doc/install/source for source installation instructions.
Go is the work of thousands of contributors. We appreciate your help!
To contribute, please read the contribution guidelines at https://golang.org/doc/contribute.html.
Note that the Go project uses the issue tracker for bug reports and proposals only. See https://golang.org/wiki/Questions for a list of places to ask questions about the Go language.