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c938051dd0
This reverts commit 719dfcf8a8.
Reason for revert: Causing crashes.
Change-Id: I0b8526dd03d82fa074ce4f97f1789eeac702b3eb
Reviewed-on: https://go-review.googlesource.com/c/go/+/709755
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: David Chase <drchase@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
53 lines
1.2 KiB
Go
53 lines
1.2 KiB
Go
// Copyright 2018 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package main
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import (
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"runtime"
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"runtime/debug"
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"unsafe"
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)
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func init() {
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register("BadTraceback", BadTraceback)
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}
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func BadTraceback() {
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// Disable GC to prevent traceback at unexpected time.
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debug.SetGCPercent(-1)
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// Out of an abundance of caution, also make sure that there are
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// no GCs actively in progress.
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runtime.GC()
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// Run badLR1 on its own stack to minimize the stack size and
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// exercise the stack bounds logic in the hex dump.
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go badLR1()
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select {}
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}
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//go:noinline
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func badLR1() {
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// We need two frames on LR machines because we'll smash this
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// frame's saved LR.
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badLR2(0)
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}
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//go:noinline
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func badLR2(arg int) {
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// Smash the return PC or saved LR.
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lrOff := unsafe.Sizeof(uintptr(0))
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if runtime.GOARCH == "ppc64" || runtime.GOARCH == "ppc64le" {
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lrOff = 32 // FIXED_FRAME or sys.MinFrameSize
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}
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lrPtr := (*uintptr)(unsafe.Pointer(uintptr(unsafe.Pointer(&arg)) - lrOff))
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*lrPtr = 0xbad
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runtime.KeepAlive(lrPtr) // prevent dead store elimination
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// Print a backtrace. This should include diagnostics for the
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// bad return PC and a hex dump.
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panic("backtrace")
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}
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