4af6b81d41
Currently both _MaxMem and _MaxArena32 represent the maximum arena size on 32-bit hosts (except on MIPS32 where _MaxMem is confusingly smaller than _MaxArena32). Clean up sysAlloc so that it always uses _MaxMem, which is the maximum arena size on both 32- and 64-bit architectures and is the arena size we allocate auxiliary structures for. This lets us simplify and unify some code paths and eliminate _MaxArena32. Fixes #18651. mheap.sysAlloc currently assumes that if the arena is small, we must be on a 32-bit machine and can therefore grow the arena to _MaxArena32. This breaks down on darwin/arm64, where _MaxMem is only 2 GB. As a result, on darwin/arm64, we only reserve spans and bitmap space for a 2 GB heap, and if the application tries to allocate beyond that, sysAlloc takes the 32-bit path, tries to grow the arena beyond 2 GB, and panics when it tries to grow the spans array allocation past its reserved size. This has probably been a problem for several releases now, but was only noticed recently because mapSpans didn't check the bounds on the span reservation until recently. Most likely it corrupted the bitmap before. By using _MaxMem consistently, we avoid thinking that we can grow the arena larger than we have auxiliary structures for. Change-Id: Ifef28cb746a3ead4b31c1d7348495c2242fef520 Reviewed-on: https://go-review.googlesource.com/35253 Reviewed-by: David Crawshaw <crawshaw@golang.org> Reviewed-by: Elias Naur <elias.naur@gmail.com> Run-TryBot: Austin Clements <austin@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> |
||
|---|---|---|
| .github | ||
| api | ||
| doc | ||
| lib/time | ||
| misc | ||
| src | ||
| test | ||
| .gitattributes | ||
| .gitignore | ||
| AUTHORS | ||
| CONTRIBUTING.md | ||
| CONTRIBUTORS | ||
| favicon.ico | ||
| LICENSE | ||
| PATENTS | ||
| README.md | ||
| robots.txt | ||
The Go Programming Language
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.
Download and Install
Binary Distributions
Official binary distributions are available at https://golang.org/dl/.
After downloading a binary release, visit https://golang.org/doc/install or load doc/install.html in your web browser for installation instructions.
Install From Source
If a binary distribution is not available for your combination of operating system and architecture, visit https://golang.org/doc/install/source or load doc/install-source.html in your web browser for source installation instructions.
Contributing
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 the Go project does not use GitHub pull requests, and that we use 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.