mirror of
https://github.com/golang/go
synced 2024-10-04 00:11:21 -06:00
c81a0ed3c5
This CL contains compiler+runtime changes that detect C code running on Go (not g0, not gsignal) stacks, and it contains corrections for what it detected. The detection works by changing the C prologue to use a different stack guard word in the G than Go prologue does. On the g0 and gsignal stacks, that stack guard word is set to the usual stack guard value. But on ordinary Go stacks, that stack guard word is set to ^0, which will make any stack split check fail. The C prologue then calls morestackc instead of morestack, and morestackc aborts the program with a message about running C code on a Go stack. This check catches all C code running on the Go stack except NOSPLIT code. The NOSPLIT code is allowed, so the check is complete. Since it is a dynamic check, the code must execute to be caught. But unlike the static checks we've been using in cmd/ld, the dynamic check works with function pointers and other indirect calls. For example it caught sigpanic being pushed onto Go stacks in the signal handlers. Fixes #8667. LGTM=khr, iant R=golang-codereviews, khr, iant CC=golang-codereviews, r https://golang.org/cl/133700043
41 lines
1010 B
Go
41 lines
1010 B
Go
// Copyright 2014 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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// +build darwin dragonfly freebsd linux netbsd openbsd solaris
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package runtime
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func signame(int32) *byte
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func sigpanic() {
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g := getg()
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if !canpanic(g) {
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gothrow("unexpected signal during runtime execution")
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}
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switch g.sig {
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case _SIGBUS:
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if g.sigcode0 == _BUS_ADRERR && g.sigcode1 < 0x1000 || g.paniconfault {
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panicmem()
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}
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print("unexpected fault address ", hex(g.sigcode1), "\n")
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gothrow("fault")
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case _SIGSEGV:
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if (g.sigcode0 == 0 || g.sigcode0 == _SEGV_MAPERR || g.sigcode0 == _SEGV_ACCERR) && g.sigcode1 < 0x1000 || g.paniconfault {
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panicmem()
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}
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print("unexpected fault address ", hex(g.sigcode1), "\n")
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gothrow("fault")
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case _SIGFPE:
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switch g.sigcode0 {
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case _FPE_INTDIV:
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panicdivide()
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case _FPE_INTOVF:
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panicoverflow()
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}
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panicfloat()
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}
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panic(errorString(gostringnocopy(signame(g.sig))))
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}
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