| commit | f266cce6763aeb1b9200dcf193826dcfba5127b7 | [log] [tgz] |
|---|---|---|
| author | Dan Scales <danscales@google.com> | Tue Nov 19 13:58:28 2019 -0800 |
| committer | Dan Scales <danscales@google.com> | Tue Jan 07 00:05:43 2020 +0000 |
| tree | 391ca663443e43d8ec5ce0b6b1b3029ebc0c07d9 | |
| parent | 6b1a3f73ed6fb1ea2a65cf9eb78cbe972bda43a7 [diff] |
runtime: avoid potential deadlock when tracing memory code In reclaimChunk, the runtime is calling traceGCSweepDone() while holding the mheap lock. traceGCSweepDone() can call traceEvent() and traceFlush(). These functions not only can get various trace locks, but they may also do memory allocations (runtime.newobject) that may end up getting the mheap lock. So, there may be either a self-deadlock or a possible deadlock between multiple threads. It seems better to release the mheap lock before calling traceGCSweepDone(). It is fine to release the lock, since the operations to get the index of the chunk of work to do are atomic. We already release the lock to call sweep, so there is no new behavior for any of the callers of reclaimChunk. With this change, mheap is a leaf lock (no other lock is ever acquired while it is held). Testing: besides normal all.bash, also ran all.bash with --long enabled, since it does longer tests of runtime/trace. Change-Id: I4f8cb66c24bb8d424f24d6c2305b4b8387409248 Reviewed-on: https://go-review.googlesource.com/c/go/+/207846 Reviewed-by: Austin Clements <austin@google.com> Reviewed-by: Michael Knyszek <mknyszek@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 or load doc/install.html in your web browser 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 or load doc/install-source.html in your web browser for source installation instructions.
Go is the work of thousands of contributors. We appreciate your help!
To contribute, please read the contribution guidelines: 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.