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9b0ea6aa27
sighandler may run during a stop-the-world without a P, so it's not allowed to have write barriers. Fix the G write to disable the write barrier (this is safe because the G is reachable from allgs) and mark the function nowritebarrier. Change-Id: I907f05d3829e24eeb15fa4d020598af36710e87e Reviewed-on: https://go-review.googlesource.com/8020 Reviewed-by: Rick Hudson <rlh@golang.org>
133 lines
3.2 KiB
Go
133 lines
3.2 KiB
Go
// Copyright 2013 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 nacl netbsd openbsd
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package runtime
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import "unsafe"
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func dumpregs(c *sigctxt) {
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print("eax ", hex(c.eax()), "\n")
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print("ebx ", hex(c.ebx()), "\n")
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print("ecx ", hex(c.ecx()), "\n")
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print("edx ", hex(c.edx()), "\n")
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print("edi ", hex(c.edi()), "\n")
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print("esi ", hex(c.esi()), "\n")
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print("ebp ", hex(c.ebp()), "\n")
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print("esp ", hex(c.esp()), "\n")
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print("eip ", hex(c.eip()), "\n")
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print("eflags ", hex(c.eflags()), "\n")
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print("cs ", hex(c.cs()), "\n")
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print("fs ", hex(c.fs()), "\n")
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print("gs ", hex(c.gs()), "\n")
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}
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// May run during STW, so write barriers are not allowed.
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//go:nowritebarrier
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func sighandler(sig uint32, info *siginfo, ctxt unsafe.Pointer, gp *g) {
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_g_ := getg()
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c := &sigctxt{info, ctxt}
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if sig == _SIGPROF {
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sigprof(uintptr(c.eip()), uintptr(c.esp()), 0, gp, _g_.m)
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return
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}
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flags := int32(_SigThrow)
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if sig < uint32(len(sigtable)) {
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flags = sigtable[sig].flags
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}
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if c.sigcode() != _SI_USER && flags&_SigPanic != 0 {
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// Make it look like a call to the signal func.
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// Have to pass arguments out of band since
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// augmenting the stack frame would break
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// the unwinding code.
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gp.sig = sig
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gp.sigcode0 = uintptr(c.sigcode())
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gp.sigcode1 = uintptr(c.sigaddr())
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gp.sigpc = uintptr(c.eip())
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if GOOS == "darwin" {
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// Work around Leopard bug that doesn't set FPE_INTDIV.
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// Look at instruction to see if it is a divide.
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// Not necessary in Snow Leopard (si_code will be != 0).
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if sig == _SIGFPE && gp.sigcode0 == 0 {
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pc := (*[4]byte)(unsafe.Pointer(gp.sigpc))
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i := 0
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if pc[i] == 0x66 { // 16-bit instruction prefix
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i++
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}
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if pc[i] == 0xF6 || pc[i] == 0xF7 {
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gp.sigcode0 = _FPE_INTDIV
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}
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}
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}
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// Only push runtime.sigpanic if rip != 0.
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// If rip == 0, probably panicked because of a
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// call to a nil func. Not pushing that onto sp will
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// make the trace look like a call to runtime.sigpanic instead.
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// (Otherwise the trace will end at runtime.sigpanic and we
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// won't get to see who faulted.)
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if c.eip() != 0 {
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sp := c.esp()
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if regSize > ptrSize {
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sp -= ptrSize
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*(*uintptr)(unsafe.Pointer(uintptr(sp))) = 0
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}
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sp -= ptrSize
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*(*uintptr)(unsafe.Pointer(uintptr(sp))) = uintptr(c.eip())
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c.set_esp(sp)
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}
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c.set_eip(uint32(funcPC(sigpanic)))
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return
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}
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if c.sigcode() == _SI_USER || flags&_SigNotify != 0 {
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if sigsend(sig) {
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return
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}
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}
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if flags&_SigKill != 0 {
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exit(2)
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}
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if flags&_SigThrow == 0 {
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return
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}
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_g_.m.throwing = 1
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setGNoWriteBarrier(&_g_.m.caughtsig, gp)
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startpanic()
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if sig < uint32(len(sigtable)) {
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print(sigtable[sig].name, "\n")
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} else {
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print("Signal ", sig, "\n")
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}
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print("PC=", hex(c.eip()), "\n")
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if _g_.m.lockedg != nil && _g_.m.ncgo > 0 && gp == _g_.m.g0 {
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print("signal arrived during cgo execution\n")
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gp = _g_.m.lockedg
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}
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print("\n")
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var docrash bool
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if gotraceback(&docrash) > 0 {
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goroutineheader(gp)
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tracebacktrap(uintptr(c.eip()), uintptr(c.esp()), 0, gp)
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tracebackothers(gp)
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print("\n")
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dumpregs(c)
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}
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if docrash {
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crash()
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}
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exit(2)
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}
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