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| author | Ian Lance Taylor <ian@gcc.gnu.org> | 2019-02-19 15:32:34 +0000 |
|---|---|---|
| committer | Ian Lance Taylor <ian@gcc.gnu.org> | 2019-02-19 15:32:34 +0000 |
| commit | 6bd37418a378bec4916ad70403375af00df91938 (patch) | |
| tree | 6cc264135130829edd8bf0fa234f727d4f929cc6 /libgo/go | |
| parent | 23c4471ee530a7a752ca8c7eff111aaa39e8d118 (diff) | |
| download | gcc-6bd37418a378bec4916ad70403375af00df91938.zip gcc-6bd37418a378bec4916ad70403375af00df91938.tar.gz gcc-6bd37418a378bec4916ad70403375af00df91938.tar.bz2 | |
runtime: abort stack scan in cases that we cannot unwind the stack
In signal-triggered stack scan, if the signal is delivered at
certain bad time (e.g. in vdso, or in the middle of setcontext?),
the unwinder may not be able to unwind the whole stack, while it
still reports _URC_END_OF_STACK. So we cannot rely on _URC_END_OF_STACK
to tell if it successfully scanned the stack. Instead, we check
the last Go frame to see it actually reached the end of the stack.
For Go-created stack, this is runtime.kickoff. For C-created
stack, we need to record the outermost Go frame when it enters
the Go side.
Also we cannot unwind the stack if the signal is delivered in the
middle of runtime.gogo, halfway through a goroutine switch, where
the g and the stack don't match. Give up in this case as well.
Reviewed-on: https://go-review.googlesource.com/c/159098
From-SVN: r269018
Diffstat (limited to 'libgo/go')
| -rw-r--r-- | libgo/go/runtime/cgo_gccgo.go | 4 | ||||
| -rw-r--r-- | libgo/go/runtime/proc.go | 3 | ||||
| -rw-r--r-- | libgo/go/runtime/runtime2.go | 1 | ||||
| -rw-r--r-- | libgo/go/runtime/stubs.go | 4 |
4 files changed, 12 insertions, 0 deletions
diff --git a/libgo/go/runtime/cgo_gccgo.go b/libgo/go/runtime/cgo_gccgo.go index aff8130..e4d27e8 100644 --- a/libgo/go/runtime/cgo_gccgo.go +++ b/libgo/go/runtime/cgo_gccgo.go @@ -80,6 +80,10 @@ func CgocallBack() { gp = getg() mp := gp.m mp.dropextram = true + + // This is a C-created stack. + // Record the outermost Go frame to help stack scan. + gp.entrysp = getcallersp() } lockOSThread() diff --git a/libgo/go/runtime/proc.go b/libgo/go/runtime/proc.go index e937563..1c944d6 100644 --- a/libgo/go/runtime/proc.go +++ b/libgo/go/runtime/proc.go @@ -1192,6 +1192,9 @@ func kickoff() { gp.param = nil } + // Record the entry SP to help stack scan. + gp.entrysp = getsp() + fv(param) goexit1() } diff --git a/libgo/go/runtime/runtime2.go b/libgo/go/runtime/runtime2.go index 4cd68da..4f823e0 100644 --- a/libgo/go/runtime/runtime2.go +++ b/libgo/go/runtime/runtime2.go @@ -433,6 +433,7 @@ type g struct { entry func(unsafe.Pointer) // goroutine function to run entryfn uintptr // function address passed to __go_go + entrysp uintptr // the stack pointer of the outermost Go frame fromgogo bool // whether entered from gogo function scanningself bool // whether goroutine is scanning its own stack diff --git a/libgo/go/runtime/stubs.go b/libgo/go/runtime/stubs.go index 9f5191b..dfdb38e 100644 --- a/libgo/go/runtime/stubs.go +++ b/libgo/go/runtime/stubs.go @@ -231,6 +231,10 @@ func getcallerpc() uintptr //go:noescape func getcallersp() uintptr // implemented as an intrinsic on all platforms +// getsp returns the stack pointer (SP) of the caller of getsp. +//go:noinline +func getsp() uintptr { return getcallersp() } + func asmcgocall(fn, arg unsafe.Pointer) int32 { throw("asmcgocall") return 0 |