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| author | Ian Lance Taylor <iant@golang.org> | 2017-08-04 10:36:40 -0700 |
|---|---|---|
| committer | Ian Lance Taylor <iant@golang.org> | 2017-08-05 18:05:41 +0000 |
| commit | f096b5b340f6e831cf80cd39cbf88d4656d232fa (patch) | |
| tree | 1814c48b303450276e9b843f5f29e6a880b0c20e | |
| parent | 3e3da5463302ff6f73a78e60fa7027d554095520 (diff) | |
| download | go-f096b5b340f6e831cf80cd39cbf88d4656d232fa.tar.gz go-f096b5b340f6e831cf80cd39cbf88d4656d232fa.zip | |
runtime: mark activeModules nosplit/nowritebarrier
The activeModules function is called by the cgo pointer checking code,
which is called by the write barrier (when GODEBUG=cgocheck=2), and as
such must be nosplit/nowritebarrier.
Fixes #21306
Change-Id: I57f2124f14de7f3872b2de9532abab15df95d45a
Reviewed-on: https://go-review.googlesource.com/53352
Reviewed-by: Austin Clements <austin@google.com>
| -rw-r--r-- | misc/cgo/errors/ptr.go | 8 | ||||
| -rw-r--r-- | src/runtime/symtab.go | 5 |
2 files changed, 13 insertions, 0 deletions
diff --git a/misc/cgo/errors/ptr.go b/misc/cgo/errors/ptr.go index 4dafbdf3c0..3e117666bf 100644 --- a/misc/cgo/errors/ptr.go +++ b/misc/cgo/errors/ptr.go @@ -343,6 +343,14 @@ var ptrTests = []ptrTest{ body: `var b C.char; p := &b; C.f((*C.u)(unsafe.Pointer(&p)))`, fail: false, }, + { + // Issue #21306. + name: "preempt-during-call", + c: `void f() {}`, + imports: []string{"runtime", "sync"}, + body: `var wg sync.WaitGroup; wg.Add(100); for i := 0; i < 100; i++ { go func(i int) { for j := 0; j < 100; j++ { C.f(); runtime.GOMAXPROCS(i) }; wg.Done() }(i) }; wg.Wait()`, + fail: false, + }, } func main() { diff --git a/src/runtime/symtab.go b/src/runtime/symtab.go index 8e410c4560..e1b41ca4ff 100644 --- a/src/runtime/symtab.go +++ b/src/runtime/symtab.go @@ -409,6 +409,11 @@ var modulesSlice unsafe.Pointer // see activeModules // // A module is active once its gcdatamask and gcbssmask have been // assembled and it is usable by the GC. +// +// This is nosplit/nowritebarrier because it is called by the +// cgo pointer checking code. +//go:nosplit +//go:nowritebarrier func activeModules() []*moduledata { p := (*[]*moduledata)(atomic.Loadp(unsafe.Pointer(&modulesSlice))) if p == nil { |