mirror of https://go.googlesource.com/go
1657 lines
55 KiB
Go
1657 lines
55 KiB
Go
// Copyright 2009 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 runtime
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import (
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"internal/abi"
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"internal/bytealg"
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"internal/goarch"
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"internal/stringslite"
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"runtime/internal/sys"
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"unsafe"
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)
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// The code in this file implements stack trace walking for all architectures.
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// The most important fact about a given architecture is whether it uses a link register.
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// On systems with link registers, the prologue for a non-leaf function stores the
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// incoming value of LR at the bottom of the newly allocated stack frame.
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// On systems without link registers (x86), the architecture pushes a return PC during
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// the call instruction, so the return PC ends up above the stack frame.
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// In this file, the return PC is always called LR, no matter how it was found.
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const usesLR = sys.MinFrameSize > 0
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const (
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// tracebackInnerFrames is the number of innermost frames to print in a
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// stack trace. The total maximum frames is tracebackInnerFrames +
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// tracebackOuterFrames.
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tracebackInnerFrames = 50
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// tracebackOuterFrames is the number of outermost frames to print in a
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// stack trace.
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tracebackOuterFrames = 50
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)
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// unwindFlags control the behavior of various unwinders.
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type unwindFlags uint8
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const (
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// unwindPrintErrors indicates that if unwinding encounters an error, it
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// should print a message and stop without throwing. This is used for things
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// like stack printing, where it's better to get incomplete information than
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// to crash. This is also used in situations where everything may not be
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// stopped nicely and the stack walk may not be able to complete, such as
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// during profiling signals or during a crash.
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//
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// If neither unwindPrintErrors or unwindSilentErrors are set, unwinding
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// performs extra consistency checks and throws on any error.
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//
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// Note that there are a small number of fatal situations that will throw
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// regardless of unwindPrintErrors or unwindSilentErrors.
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unwindPrintErrors unwindFlags = 1 << iota
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// unwindSilentErrors silently ignores errors during unwinding.
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unwindSilentErrors
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// unwindTrap indicates that the initial PC and SP are from a trap, not a
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// return PC from a call.
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//
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// The unwindTrap flag is updated during unwinding. If set, frame.pc is the
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// address of a faulting instruction instead of the return address of a
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// call. It also means the liveness at pc may not be known.
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//
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// TODO: Distinguish frame.continpc, which is really the stack map PC, from
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// the actual continuation PC, which is computed differently depending on
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// this flag and a few other things.
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unwindTrap
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// unwindJumpStack indicates that, if the traceback is on a system stack, it
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// should resume tracing at the user stack when the system stack is
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// exhausted.
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unwindJumpStack
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)
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// An unwinder iterates the physical stack frames of a Go sack.
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//
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// Typical use of an unwinder looks like:
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//
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// var u unwinder
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// for u.init(gp, 0); u.valid(); u.next() {
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// // ... use frame info in u ...
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// }
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//
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// Implementation note: This is carefully structured to be pointer-free because
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// tracebacks happen in places that disallow write barriers (e.g., signals).
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// Even if this is stack-allocated, its pointer-receiver methods don't know that
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// their receiver is on the stack, so they still emit write barriers. Here we
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// address that by carefully avoiding any pointers in this type. Another
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// approach would be to split this into a mutable part that's passed by pointer
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// but contains no pointers itself and an immutable part that's passed and
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// returned by value and can contain pointers. We could potentially hide that
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// we're doing that in trivial methods that are inlined into the caller that has
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// the stack allocation, but that's fragile.
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type unwinder struct {
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// frame is the current physical stack frame, or all 0s if
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// there is no frame.
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frame stkframe
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// g is the G who's stack is being unwound. If the
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// unwindJumpStack flag is set and the unwinder jumps stacks,
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// this will be different from the initial G.
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g guintptr
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// cgoCtxt is the index into g.cgoCtxt of the next frame on the cgo stack.
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// The cgo stack is unwound in tandem with the Go stack as we find marker frames.
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cgoCtxt int
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// calleeFuncID is the function ID of the caller of the current
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// frame.
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calleeFuncID abi.FuncID
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// flags are the flags to this unwind. Some of these are updated as we
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// unwind (see the flags documentation).
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flags unwindFlags
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}
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// init initializes u to start unwinding gp's stack and positions the
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// iterator on gp's innermost frame. gp must not be the current G.
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//
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// A single unwinder can be reused for multiple unwinds.
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func (u *unwinder) init(gp *g, flags unwindFlags) {
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// Implementation note: This starts the iterator on the first frame and we
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// provide a "valid" method. Alternatively, this could start in a "before
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// the first frame" state and "next" could return whether it was able to
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// move to the next frame, but that's both more awkward to use in a "for"
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// loop and is harder to implement because we have to do things differently
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// for the first frame.
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u.initAt(^uintptr(0), ^uintptr(0), ^uintptr(0), gp, flags)
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}
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func (u *unwinder) initAt(pc0, sp0, lr0 uintptr, gp *g, flags unwindFlags) {
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// Don't call this "g"; it's too easy get "g" and "gp" confused.
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if ourg := getg(); ourg == gp && ourg == ourg.m.curg {
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// The starting sp has been passed in as a uintptr, and the caller may
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// have other uintptr-typed stack references as well.
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// If during one of the calls that got us here or during one of the
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// callbacks below the stack must be grown, all these uintptr references
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// to the stack will not be updated, and traceback will continue
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// to inspect the old stack memory, which may no longer be valid.
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// Even if all the variables were updated correctly, it is not clear that
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// we want to expose a traceback that begins on one stack and ends
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// on another stack. That could confuse callers quite a bit.
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// Instead, we require that initAt and any other function that
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// accepts an sp for the current goroutine (typically obtained by
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// calling getcallersp) must not run on that goroutine's stack but
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// instead on the g0 stack.
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throw("cannot trace user goroutine on its own stack")
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}
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if pc0 == ^uintptr(0) && sp0 == ^uintptr(0) { // Signal to fetch saved values from gp.
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if gp.syscallsp != 0 {
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pc0 = gp.syscallpc
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sp0 = gp.syscallsp
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if usesLR {
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lr0 = 0
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}
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} else {
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pc0 = gp.sched.pc
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sp0 = gp.sched.sp
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if usesLR {
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lr0 = gp.sched.lr
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}
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}
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}
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var frame stkframe
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frame.pc = pc0
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frame.sp = sp0
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if usesLR {
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frame.lr = lr0
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}
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// If the PC is zero, it's likely a nil function call.
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// Start in the caller's frame.
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if frame.pc == 0 {
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if usesLR {
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frame.pc = *(*uintptr)(unsafe.Pointer(frame.sp))
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frame.lr = 0
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} else {
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frame.pc = *(*uintptr)(unsafe.Pointer(frame.sp))
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frame.sp += goarch.PtrSize
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}
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}
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// internal/runtime/atomic functions call into kernel helpers on
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// arm < 7. See internal/runtime/atomic/sys_linux_arm.s.
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//
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// Start in the caller's frame.
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if GOARCH == "arm" && goarm < 7 && GOOS == "linux" && frame.pc&0xffff0000 == 0xffff0000 {
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// Note that the calls are simple BL without pushing the return
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// address, so we use LR directly.
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//
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// The kernel helpers are frameless leaf functions, so SP and
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// LR are not touched.
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frame.pc = frame.lr
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frame.lr = 0
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}
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f := findfunc(frame.pc)
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if !f.valid() {
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if flags&unwindSilentErrors == 0 {
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print("runtime: g ", gp.goid, " gp=", gp, ": unknown pc ", hex(frame.pc), "\n")
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tracebackHexdump(gp.stack, &frame, 0)
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}
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if flags&(unwindPrintErrors|unwindSilentErrors) == 0 {
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throw("unknown pc")
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}
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*u = unwinder{}
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return
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}
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frame.fn = f
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// Populate the unwinder.
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*u = unwinder{
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frame: frame,
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g: gp.guintptr(),
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cgoCtxt: len(gp.cgoCtxt) - 1,
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calleeFuncID: abi.FuncIDNormal,
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flags: flags,
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}
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isSyscall := frame.pc == pc0 && frame.sp == sp0 && pc0 == gp.syscallpc && sp0 == gp.syscallsp
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u.resolveInternal(true, isSyscall)
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}
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func (u *unwinder) valid() bool {
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return u.frame.pc != 0
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}
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// resolveInternal fills in u.frame based on u.frame.fn, pc, and sp.
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//
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// innermost indicates that this is the first resolve on this stack. If
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// innermost is set, isSyscall indicates that the PC/SP was retrieved from
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// gp.syscall*; this is otherwise ignored.
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//
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// On entry, u.frame contains:
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// - fn is the running function.
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// - pc is the PC in the running function.
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// - sp is the stack pointer at that program counter.
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// - For the innermost frame on LR machines, lr is the program counter that called fn.
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//
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// On return, u.frame contains:
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// - fp is the stack pointer of the caller.
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// - lr is the program counter that called fn.
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// - varp, argp, and continpc are populated for the current frame.
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//
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// If fn is a stack-jumping function, resolveInternal can change the entire
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// frame state to follow that stack jump.
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//
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// This is internal to unwinder.
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func (u *unwinder) resolveInternal(innermost, isSyscall bool) {
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frame := &u.frame
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gp := u.g.ptr()
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f := frame.fn
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if f.pcsp == 0 {
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// No frame information, must be external function, like race support.
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// See golang.org/issue/13568.
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u.finishInternal()
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return
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}
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// Compute function info flags.
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flag := f.flag
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if f.funcID == abi.FuncID_cgocallback {
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// cgocallback does write SP to switch from the g0 to the curg stack,
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// but it carefully arranges that during the transition BOTH stacks
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// have cgocallback frame valid for unwinding through.
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// So we don't need to exclude it with the other SP-writing functions.
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flag &^= abi.FuncFlagSPWrite
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}
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if isSyscall {
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// Some Syscall functions write to SP, but they do so only after
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// saving the entry PC/SP using entersyscall.
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// Since we are using the entry PC/SP, the later SP write doesn't matter.
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flag &^= abi.FuncFlagSPWrite
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}
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// Found an actual function.
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// Derive frame pointer.
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if frame.fp == 0 {
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// Jump over system stack transitions. If we're on g0 and there's a user
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// goroutine, try to jump. Otherwise this is a regular call.
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// We also defensively check that this won't switch M's on us,
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// which could happen at critical points in the scheduler.
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// This ensures gp.m doesn't change from a stack jump.
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if u.flags&unwindJumpStack != 0 && gp == gp.m.g0 && gp.m.curg != nil && gp.m.curg.m == gp.m {
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switch f.funcID {
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case abi.FuncID_morestack:
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// morestack does not return normally -- newstack()
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// gogo's to curg.sched. Match that.
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// This keeps morestack() from showing up in the backtrace,
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// but that makes some sense since it'll never be returned
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// to.
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gp = gp.m.curg
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u.g.set(gp)
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frame.pc = gp.sched.pc
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frame.fn = findfunc(frame.pc)
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f = frame.fn
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flag = f.flag
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frame.lr = gp.sched.lr
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frame.sp = gp.sched.sp
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u.cgoCtxt = len(gp.cgoCtxt) - 1
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case abi.FuncID_systemstack:
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// systemstack returns normally, so just follow the
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// stack transition.
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if usesLR && funcspdelta(f, frame.pc) == 0 {
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// We're at the function prologue and the stack
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// switch hasn't happened, or epilogue where we're
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// about to return. Just unwind normally.
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// Do this only on LR machines because on x86
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// systemstack doesn't have an SP delta (the CALL
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// instruction opens the frame), therefore no way
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// to check.
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flag &^= abi.FuncFlagSPWrite
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break
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}
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gp = gp.m.curg
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u.g.set(gp)
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frame.sp = gp.sched.sp
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u.cgoCtxt = len(gp.cgoCtxt) - 1
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flag &^= abi.FuncFlagSPWrite
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}
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}
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frame.fp = frame.sp + uintptr(funcspdelta(f, frame.pc))
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if !usesLR {
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// On x86, call instruction pushes return PC before entering new function.
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frame.fp += goarch.PtrSize
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}
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}
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// Derive link register.
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if flag&abi.FuncFlagTopFrame != 0 {
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// This function marks the top of the stack. Stop the traceback.
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frame.lr = 0
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} else if flag&abi.FuncFlagSPWrite != 0 && (!innermost || u.flags&(unwindPrintErrors|unwindSilentErrors) != 0) {
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// The function we are in does a write to SP that we don't know
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// how to encode in the spdelta table. Examples include context
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// switch routines like runtime.gogo but also any code that switches
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// to the g0 stack to run host C code.
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// We can't reliably unwind the SP (we might not even be on
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// the stack we think we are), so stop the traceback here.
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//
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// The one exception (encoded in the complex condition above) is that
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// we assume if we're doing a precise traceback, and this is the
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// innermost frame, that the SPWRITE function voluntarily preempted itself on entry
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// during the stack growth check. In that case, the function has
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// not yet had a chance to do any writes to SP and is safe to unwind.
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// isAsyncSafePoint does not allow assembly functions to be async preempted,
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// and preemptPark double-checks that SPWRITE functions are not async preempted.
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// So for GC stack traversal, we can safely ignore SPWRITE for the innermost frame,
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// but farther up the stack we'd better not find any.
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// This is somewhat imprecise because we're just guessing that we're in the stack
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// growth check. It would be better if SPWRITE were encoded in the spdelta
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// table so we would know for sure that we were still in safe code.
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//
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// uSE uPE inn | action
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// T _ _ | frame.lr = 0
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// F T _ | frame.lr = 0
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// F F F | print; panic
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// F F T | ignore SPWrite
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if u.flags&(unwindPrintErrors|unwindSilentErrors) == 0 && !innermost {
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println("traceback: unexpected SPWRITE function", funcname(f))
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throw("traceback")
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}
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frame.lr = 0
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} else {
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var lrPtr uintptr
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if usesLR {
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if innermost && frame.sp < frame.fp || frame.lr == 0 {
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lrPtr = frame.sp
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frame.lr = *(*uintptr)(unsafe.Pointer(lrPtr))
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}
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} else {
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if frame.lr == 0 {
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lrPtr = frame.fp - goarch.PtrSize
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frame.lr = *(*uintptr)(unsafe.Pointer(lrPtr))
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}
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}
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}
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frame.varp = frame.fp
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if !usesLR {
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// On x86, call instruction pushes return PC before entering new function.
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frame.varp -= goarch.PtrSize
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}
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// For architectures with frame pointers, if there's
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// a frame, then there's a saved frame pointer here.
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//
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// NOTE: This code is not as general as it looks.
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// On x86, the ABI is to save the frame pointer word at the
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// top of the stack frame, so we have to back down over it.
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// On arm64, the frame pointer should be at the bottom of
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// the stack (with R29 (aka FP) = RSP), in which case we would
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// not want to do the subtraction here. But we started out without
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// any frame pointer, and when we wanted to add it, we didn't
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// want to break all the assembly doing direct writes to 8(RSP)
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// to set the first parameter to a called function.
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// So we decided to write the FP link *below* the stack pointer
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// (with R29 = RSP - 8 in Go functions).
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// This is technically ABI-compatible but not standard.
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// And it happens to end up mimicking the x86 layout.
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// Other architectures may make different decisions.
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if frame.varp > frame.sp && framepointer_enabled {
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frame.varp -= goarch.PtrSize
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}
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frame.argp = frame.fp + sys.MinFrameSize
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// Determine frame's 'continuation PC', where it can continue.
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// Normally this is the return address on the stack, but if sigpanic
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// is immediately below this function on the stack, then the frame
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// stopped executing due to a trap, and frame.pc is probably not
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// a safe point for looking up liveness information. In this panicking case,
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// the function either doesn't return at all (if it has no defers or if the
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// defers do not recover) or it returns from one of the calls to
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// deferproc a second time (if the corresponding deferred func recovers).
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// In the latter case, use a deferreturn call site as the continuation pc.
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frame.continpc = frame.pc
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if u.calleeFuncID == abi.FuncID_sigpanic {
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if frame.fn.deferreturn != 0 {
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frame.continpc = frame.fn.entry() + uintptr(frame.fn.deferreturn) + 1
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// Note: this may perhaps keep return variables alive longer than
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// strictly necessary, as we are using "function has a defer statement"
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// as a proxy for "function actually deferred something". It seems
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// to be a minor drawback. (We used to actually look through the
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// gp._defer for a defer corresponding to this function, but that
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// is hard to do with defer records on the stack during a stack copy.)
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// Note: the +1 is to offset the -1 that
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// stack.go:getStackMap does to back up a return
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// address make sure the pc is in the CALL instruction.
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} else {
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frame.continpc = 0
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}
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}
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}
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func (u *unwinder) next() {
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frame := &u.frame
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f := frame.fn
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gp := u.g.ptr()
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// Do not unwind past the bottom of the stack.
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if frame.lr == 0 {
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u.finishInternal()
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return
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}
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flr := findfunc(frame.lr)
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if !flr.valid() {
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// This happens if you get a profiling interrupt at just the wrong time.
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// In that context it is okay to stop early.
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// But if no error flags are set, we're doing a garbage collection and must
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// get everything, so crash loudly.
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fail := u.flags&(unwindPrintErrors|unwindSilentErrors) == 0
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doPrint := u.flags&unwindSilentErrors == 0
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if doPrint && gp.m.incgo && f.funcID == abi.FuncID_sigpanic {
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// We can inject sigpanic
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// calls directly into C code,
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// in which case we'll see a C
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// return PC. Don't complain.
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doPrint = false
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}
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if fail || doPrint {
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print("runtime: g ", gp.goid, ": unexpected return pc for ", funcname(f), " called from ", hex(frame.lr), "\n")
|
|
tracebackHexdump(gp.stack, frame, 0)
|
|
}
|
|
if fail {
|
|
throw("unknown caller pc")
|
|
}
|
|
frame.lr = 0
|
|
u.finishInternal()
|
|
return
|
|
}
|
|
|
|
if frame.pc == frame.lr && frame.sp == frame.fp {
|
|
// If the next frame is identical to the current frame, we cannot make progress.
|
|
print("runtime: traceback stuck. pc=", hex(frame.pc), " sp=", hex(frame.sp), "\n")
|
|
tracebackHexdump(gp.stack, frame, frame.sp)
|
|
throw("traceback stuck")
|
|
}
|
|
|
|
injectedCall := f.funcID == abi.FuncID_sigpanic || f.funcID == abi.FuncID_asyncPreempt || f.funcID == abi.FuncID_debugCallV2
|
|
if injectedCall {
|
|
u.flags |= unwindTrap
|
|
} else {
|
|
u.flags &^= unwindTrap
|
|
}
|
|
|
|
// Unwind to next frame.
|
|
u.calleeFuncID = f.funcID
|
|
frame.fn = flr
|
|
frame.pc = frame.lr
|
|
frame.lr = 0
|
|
frame.sp = frame.fp
|
|
frame.fp = 0
|
|
|
|
// On link register architectures, sighandler saves the LR on stack
|
|
// before faking a call.
|
|
if usesLR && injectedCall {
|
|
x := *(*uintptr)(unsafe.Pointer(frame.sp))
|
|
frame.sp += alignUp(sys.MinFrameSize, sys.StackAlign)
|
|
f = findfunc(frame.pc)
|
|
frame.fn = f
|
|
if !f.valid() {
|
|
frame.pc = x
|
|
} else if funcspdelta(f, frame.pc) == 0 {
|
|
frame.lr = x
|
|
}
|
|
}
|
|
|
|
u.resolveInternal(false, false)
|
|
}
|
|
|
|
// finishInternal is an unwinder-internal helper called after the stack has been
|
|
// exhausted. It sets the unwinder to an invalid state and checks that it
|
|
// successfully unwound the entire stack.
|
|
func (u *unwinder) finishInternal() {
|
|
u.frame.pc = 0
|
|
|
|
// Note that panic != nil is okay here: there can be leftover panics,
|
|
// because the defers on the panic stack do not nest in frame order as
|
|
// they do on the defer stack. If you have:
|
|
//
|
|
// frame 1 defers d1
|
|
// frame 2 defers d2
|
|
// frame 3 defers d3
|
|
// frame 4 panics
|
|
// frame 4's panic starts running defers
|
|
// frame 5, running d3, defers d4
|
|
// frame 5 panics
|
|
// frame 5's panic starts running defers
|
|
// frame 6, running d4, garbage collects
|
|
// frame 6, running d2, garbage collects
|
|
//
|
|
// During the execution of d4, the panic stack is d4 -> d3, which
|
|
// is nested properly, and we'll treat frame 3 as resumable, because we
|
|
// can find d3. (And in fact frame 3 is resumable. If d4 recovers
|
|
// and frame 5 continues running, d3, d3 can recover and we'll
|
|
// resume execution in (returning from) frame 3.)
|
|
//
|
|
// During the execution of d2, however, the panic stack is d2 -> d3,
|
|
// which is inverted. The scan will match d2 to frame 2 but having
|
|
// d2 on the stack until then means it will not match d3 to frame 3.
|
|
// This is okay: if we're running d2, then all the defers after d2 have
|
|
// completed and their corresponding frames are dead. Not finding d3
|
|
// for frame 3 means we'll set frame 3's continpc == 0, which is correct
|
|
// (frame 3 is dead). At the end of the walk the panic stack can thus
|
|
// contain defers (d3 in this case) for dead frames. The inversion here
|
|
// always indicates a dead frame, and the effect of the inversion on the
|
|
// scan is to hide those dead frames, so the scan is still okay:
|
|
// what's left on the panic stack are exactly (and only) the dead frames.
|
|
//
|
|
// We require callback != nil here because only when callback != nil
|
|
// do we know that gentraceback is being called in a "must be correct"
|
|
// context as opposed to a "best effort" context. The tracebacks with
|
|
// callbacks only happen when everything is stopped nicely.
|
|
// At other times, such as when gathering a stack for a profiling signal
|
|
// or when printing a traceback during a crash, everything may not be
|
|
// stopped nicely, and the stack walk may not be able to complete.
|
|
gp := u.g.ptr()
|
|
if u.flags&(unwindPrintErrors|unwindSilentErrors) == 0 && u.frame.sp != gp.stktopsp {
|
|
print("runtime: g", gp.goid, ": frame.sp=", hex(u.frame.sp), " top=", hex(gp.stktopsp), "\n")
|
|
print("\tstack=[", hex(gp.stack.lo), "-", hex(gp.stack.hi), "\n")
|
|
throw("traceback did not unwind completely")
|
|
}
|
|
}
|
|
|
|
// symPC returns the PC that should be used for symbolizing the current frame.
|
|
// Specifically, this is the PC of the last instruction executed in this frame.
|
|
//
|
|
// If this frame did a normal call, then frame.pc is a return PC, so this will
|
|
// return frame.pc-1, which points into the CALL instruction. If the frame was
|
|
// interrupted by a signal (e.g., profiler, segv, etc) then frame.pc is for the
|
|
// trapped instruction, so this returns frame.pc. See issue #34123. Finally,
|
|
// frame.pc can be at function entry when the frame is initialized without
|
|
// actually running code, like in runtime.mstart, in which case this returns
|
|
// frame.pc because that's the best we can do.
|
|
func (u *unwinder) symPC() uintptr {
|
|
if u.flags&unwindTrap == 0 && u.frame.pc > u.frame.fn.entry() {
|
|
// Regular call.
|
|
return u.frame.pc - 1
|
|
}
|
|
// Trapping instruction or we're at the function entry point.
|
|
return u.frame.pc
|
|
}
|
|
|
|
// cgoCallers populates pcBuf with the cgo callers of the current frame using
|
|
// the registered cgo unwinder. It returns the number of PCs written to pcBuf.
|
|
// If the current frame is not a cgo frame or if there's no registered cgo
|
|
// unwinder, it returns 0.
|
|
func (u *unwinder) cgoCallers(pcBuf []uintptr) int {
|
|
if cgoTraceback == nil || u.frame.fn.funcID != abi.FuncID_cgocallback || u.cgoCtxt < 0 {
|
|
// We don't have a cgo unwinder (typical case), or we do but we're not
|
|
// in a cgo frame or we're out of cgo context.
|
|
return 0
|
|
}
|
|
|
|
ctxt := u.g.ptr().cgoCtxt[u.cgoCtxt]
|
|
u.cgoCtxt--
|
|
cgoContextPCs(ctxt, pcBuf)
|
|
for i, pc := range pcBuf {
|
|
if pc == 0 {
|
|
return i
|
|
}
|
|
}
|
|
return len(pcBuf)
|
|
}
|
|
|
|
// tracebackPCs populates pcBuf with the return addresses for each frame from u
|
|
// and returns the number of PCs written to pcBuf. The returned PCs correspond
|
|
// to "logical frames" rather than "physical frames"; that is if A is inlined
|
|
// into B, this will still return a PCs for both A and B. This also includes PCs
|
|
// generated by the cgo unwinder, if one is registered.
|
|
//
|
|
// If skip != 0, this skips this many logical frames.
|
|
//
|
|
// Callers should set the unwindSilentErrors flag on u.
|
|
func tracebackPCs(u *unwinder, skip int, pcBuf []uintptr) int {
|
|
var cgoBuf [32]uintptr
|
|
n := 0
|
|
for ; n < len(pcBuf) && u.valid(); u.next() {
|
|
f := u.frame.fn
|
|
cgoN := u.cgoCallers(cgoBuf[:])
|
|
|
|
// TODO: Why does &u.cache cause u to escape? (Same in traceback2)
|
|
for iu, uf := newInlineUnwinder(f, u.symPC()); n < len(pcBuf) && uf.valid(); uf = iu.next(uf) {
|
|
sf := iu.srcFunc(uf)
|
|
if sf.funcID == abi.FuncIDWrapper && elideWrapperCalling(u.calleeFuncID) {
|
|
// ignore wrappers
|
|
} else if skip > 0 {
|
|
skip--
|
|
} else {
|
|
// Callers expect the pc buffer to contain return addresses
|
|
// and do the -1 themselves, so we add 1 to the call pc to
|
|
// create a "return pc". Since there is no actual call, here
|
|
// "return pc" just means a pc you subtract 1 from to get
|
|
// the pc of the "call". The actual no-op we insert may or
|
|
// may not be 1 byte.
|
|
pcBuf[n] = uf.pc + 1
|
|
n++
|
|
}
|
|
u.calleeFuncID = sf.funcID
|
|
}
|
|
// Add cgo frames (if we're done skipping over the requested number of
|
|
// Go frames).
|
|
if skip == 0 {
|
|
n += copy(pcBuf[n:], cgoBuf[:cgoN])
|
|
}
|
|
}
|
|
return n
|
|
}
|
|
|
|
// printArgs prints function arguments in traceback.
|
|
func printArgs(f funcInfo, argp unsafe.Pointer, pc uintptr) {
|
|
p := (*[abi.TraceArgsMaxLen]uint8)(funcdata(f, abi.FUNCDATA_ArgInfo))
|
|
if p == nil {
|
|
return
|
|
}
|
|
|
|
liveInfo := funcdata(f, abi.FUNCDATA_ArgLiveInfo)
|
|
liveIdx := pcdatavalue(f, abi.PCDATA_ArgLiveIndex, pc)
|
|
startOffset := uint8(0xff) // smallest offset that needs liveness info (slots with a lower offset is always live)
|
|
if liveInfo != nil {
|
|
startOffset = *(*uint8)(liveInfo)
|
|
}
|
|
|
|
isLive := func(off, slotIdx uint8) bool {
|
|
if liveInfo == nil || liveIdx <= 0 {
|
|
return true // no liveness info, always live
|
|
}
|
|
if off < startOffset {
|
|
return true
|
|
}
|
|
bits := *(*uint8)(add(liveInfo, uintptr(liveIdx)+uintptr(slotIdx/8)))
|
|
return bits&(1<<(slotIdx%8)) != 0
|
|
}
|
|
|
|
print1 := func(off, sz, slotIdx uint8) {
|
|
x := readUnaligned64(add(argp, uintptr(off)))
|
|
// mask out irrelevant bits
|
|
if sz < 8 {
|
|
shift := 64 - sz*8
|
|
if goarch.BigEndian {
|
|
x = x >> shift
|
|
} else {
|
|
x = x << shift >> shift
|
|
}
|
|
}
|
|
print(hex(x))
|
|
if !isLive(off, slotIdx) {
|
|
print("?")
|
|
}
|
|
}
|
|
|
|
start := true
|
|
printcomma := func() {
|
|
if !start {
|
|
print(", ")
|
|
}
|
|
}
|
|
pi := 0
|
|
slotIdx := uint8(0) // register arg spill slot index
|
|
printloop:
|
|
for {
|
|
o := p[pi]
|
|
pi++
|
|
switch o {
|
|
case abi.TraceArgsEndSeq:
|
|
break printloop
|
|
case abi.TraceArgsStartAgg:
|
|
printcomma()
|
|
print("{")
|
|
start = true
|
|
continue
|
|
case abi.TraceArgsEndAgg:
|
|
print("}")
|
|
case abi.TraceArgsDotdotdot:
|
|
printcomma()
|
|
print("...")
|
|
case abi.TraceArgsOffsetTooLarge:
|
|
printcomma()
|
|
print("_")
|
|
default:
|
|
printcomma()
|
|
sz := p[pi]
|
|
pi++
|
|
print1(o, sz, slotIdx)
|
|
if o >= startOffset {
|
|
slotIdx++
|
|
}
|
|
}
|
|
start = false
|
|
}
|
|
}
|
|
|
|
// funcNamePiecesForPrint returns the function name for printing to the user.
|
|
// It returns three pieces so it doesn't need an allocation for string
|
|
// concatenation.
|
|
func funcNamePiecesForPrint(name string) (string, string, string) {
|
|
// Replace the shape name in generic function with "...".
|
|
i := bytealg.IndexByteString(name, '[')
|
|
if i < 0 {
|
|
return name, "", ""
|
|
}
|
|
j := len(name) - 1
|
|
for name[j] != ']' {
|
|
j--
|
|
}
|
|
if j <= i {
|
|
return name, "", ""
|
|
}
|
|
return name[:i], "[...]", name[j+1:]
|
|
}
|
|
|
|
// funcNameForPrint returns the function name for printing to the user.
|
|
func funcNameForPrint(name string) string {
|
|
a, b, c := funcNamePiecesForPrint(name)
|
|
return a + b + c
|
|
}
|
|
|
|
// printFuncName prints a function name. name is the function name in
|
|
// the binary's func data table.
|
|
func printFuncName(name string) {
|
|
if name == "runtime.gopanic" {
|
|
print("panic")
|
|
return
|
|
}
|
|
a, b, c := funcNamePiecesForPrint(name)
|
|
print(a, b, c)
|
|
}
|
|
|
|
func printcreatedby(gp *g) {
|
|
// Show what created goroutine, except main goroutine (goid 1).
|
|
pc := gp.gopc
|
|
f := findfunc(pc)
|
|
if f.valid() && showframe(f.srcFunc(), gp, false, abi.FuncIDNormal) && gp.goid != 1 {
|
|
printcreatedby1(f, pc, gp.parentGoid)
|
|
}
|
|
}
|
|
|
|
func printcreatedby1(f funcInfo, pc uintptr, goid uint64) {
|
|
print("created by ")
|
|
printFuncName(funcname(f))
|
|
if goid != 0 {
|
|
print(" in goroutine ", goid)
|
|
}
|
|
print("\n")
|
|
tracepc := pc // back up to CALL instruction for funcline.
|
|
if pc > f.entry() {
|
|
tracepc -= sys.PCQuantum
|
|
}
|
|
file, line := funcline(f, tracepc)
|
|
print("\t", file, ":", line)
|
|
if pc > f.entry() {
|
|
print(" +", hex(pc-f.entry()))
|
|
}
|
|
print("\n")
|
|
}
|
|
|
|
func traceback(pc, sp, lr uintptr, gp *g) {
|
|
traceback1(pc, sp, lr, gp, 0)
|
|
}
|
|
|
|
// tracebacktrap is like traceback but expects that the PC and SP were obtained
|
|
// from a trap, not from gp->sched or gp->syscallpc/gp->syscallsp or getcallerpc/getcallersp.
|
|
// Because they are from a trap instead of from a saved pair,
|
|
// the initial PC must not be rewound to the previous instruction.
|
|
// (All the saved pairs record a PC that is a return address, so we
|
|
// rewind it into the CALL instruction.)
|
|
// If gp.m.libcall{g,pc,sp} information is available, it uses that information in preference to
|
|
// the pc/sp/lr passed in.
|
|
func tracebacktrap(pc, sp, lr uintptr, gp *g) {
|
|
if gp.m.libcallsp != 0 {
|
|
// We're in C code somewhere, traceback from the saved position.
|
|
traceback1(gp.m.libcallpc, gp.m.libcallsp, 0, gp.m.libcallg.ptr(), 0)
|
|
return
|
|
}
|
|
traceback1(pc, sp, lr, gp, unwindTrap)
|
|
}
|
|
|
|
func traceback1(pc, sp, lr uintptr, gp *g, flags unwindFlags) {
|
|
// If the goroutine is in cgo, and we have a cgo traceback, print that.
|
|
if iscgo && gp.m != nil && gp.m.ncgo > 0 && gp.syscallsp != 0 && gp.m.cgoCallers != nil && gp.m.cgoCallers[0] != 0 {
|
|
// Lock cgoCallers so that a signal handler won't
|
|
// change it, copy the array, reset it, unlock it.
|
|
// We are locked to the thread and are not running
|
|
// concurrently with a signal handler.
|
|
// We just have to stop a signal handler from interrupting
|
|
// in the middle of our copy.
|
|
gp.m.cgoCallersUse.Store(1)
|
|
cgoCallers := *gp.m.cgoCallers
|
|
gp.m.cgoCallers[0] = 0
|
|
gp.m.cgoCallersUse.Store(0)
|
|
|
|
printCgoTraceback(&cgoCallers)
|
|
}
|
|
|
|
if readgstatus(gp)&^_Gscan == _Gsyscall {
|
|
// Override registers if blocked in system call.
|
|
pc = gp.syscallpc
|
|
sp = gp.syscallsp
|
|
flags &^= unwindTrap
|
|
}
|
|
if gp.m != nil && gp.m.vdsoSP != 0 {
|
|
// Override registers if running in VDSO. This comes after the
|
|
// _Gsyscall check to cover VDSO calls after entersyscall.
|
|
pc = gp.m.vdsoPC
|
|
sp = gp.m.vdsoSP
|
|
flags &^= unwindTrap
|
|
}
|
|
|
|
// Print traceback.
|
|
//
|
|
// We print the first tracebackInnerFrames frames, and the last
|
|
// tracebackOuterFrames frames. There are many possible approaches to this.
|
|
// There are various complications to this:
|
|
//
|
|
// - We'd prefer to walk the stack once because in really bad situations
|
|
// traceback may crash (and we want as much output as possible) or the stack
|
|
// may be changing.
|
|
//
|
|
// - Each physical frame can represent several logical frames, so we might
|
|
// have to pause in the middle of a physical frame and pick up in the middle
|
|
// of a physical frame.
|
|
//
|
|
// - The cgo symbolizer can expand a cgo PC to more than one logical frame,
|
|
// and involves juggling state on the C side that we don't manage. Since its
|
|
// expansion state is managed on the C side, we can't capture the expansion
|
|
// state part way through, and because the output strings are managed on the
|
|
// C side, we can't capture the output. Thus, our only choice is to replay a
|
|
// whole expansion, potentially discarding some of it.
|
|
//
|
|
// Rejected approaches:
|
|
//
|
|
// - Do two passes where the first pass just counts and the second pass does
|
|
// all the printing. This is undesirable if the stack is corrupted or changing
|
|
// because we won't see a partial stack if we panic.
|
|
//
|
|
// - Keep a ring buffer of the last N logical frames and use this to print
|
|
// the bottom frames once we reach the end of the stack. This works, but
|
|
// requires keeping a surprising amount of state on the stack, and we have
|
|
// to run the cgo symbolizer twice—once to count frames, and a second to
|
|
// print them—since we can't retain the strings it returns.
|
|
//
|
|
// Instead, we print the outer frames, and if we reach that limit, we clone
|
|
// the unwinder, count the remaining frames, and then skip forward and
|
|
// finish printing from the clone. This makes two passes over the outer part
|
|
// of the stack, but the single pass over the inner part ensures that's
|
|
// printed immediately and not revisited. It keeps minimal state on the
|
|
// stack. And through a combination of skip counts and limits, we can do all
|
|
// of the steps we need with a single traceback printer implementation.
|
|
//
|
|
// We could be more lax about exactly how many frames we print, for example
|
|
// always stopping and resuming on physical frame boundaries, or at least
|
|
// cgo expansion boundaries. It's not clear that's much simpler.
|
|
flags |= unwindPrintErrors
|
|
var u unwinder
|
|
tracebackWithRuntime := func(showRuntime bool) int {
|
|
const maxInt int = 0x7fffffff
|
|
u.initAt(pc, sp, lr, gp, flags)
|
|
n, lastN := traceback2(&u, showRuntime, 0, tracebackInnerFrames)
|
|
if n < tracebackInnerFrames {
|
|
// We printed the whole stack.
|
|
return n
|
|
}
|
|
// Clone the unwinder and figure out how many frames are left. This
|
|
// count will include any logical frames already printed for u's current
|
|
// physical frame.
|
|
u2 := u
|
|
remaining, _ := traceback2(&u, showRuntime, maxInt, 0)
|
|
elide := remaining - lastN - tracebackOuterFrames
|
|
if elide > 0 {
|
|
print("...", elide, " frames elided...\n")
|
|
traceback2(&u2, showRuntime, lastN+elide, tracebackOuterFrames)
|
|
} else if elide <= 0 {
|
|
// There are tracebackOuterFrames or fewer frames left to print.
|
|
// Just print the rest of the stack.
|
|
traceback2(&u2, showRuntime, lastN, tracebackOuterFrames)
|
|
}
|
|
return n
|
|
}
|
|
// By default, omits runtime frames. If that means we print nothing at all,
|
|
// repeat forcing all frames printed.
|
|
if tracebackWithRuntime(false) == 0 {
|
|
tracebackWithRuntime(true)
|
|
}
|
|
printcreatedby(gp)
|
|
|
|
if gp.ancestors == nil {
|
|
return
|
|
}
|
|
for _, ancestor := range *gp.ancestors {
|
|
printAncestorTraceback(ancestor)
|
|
}
|
|
}
|
|
|
|
// traceback2 prints a stack trace starting at u. It skips the first "skip"
|
|
// logical frames, after which it prints at most "max" logical frames. It
|
|
// returns n, which is the number of logical frames skipped and printed, and
|
|
// lastN, which is the number of logical frames skipped or printed just in the
|
|
// physical frame that u references.
|
|
func traceback2(u *unwinder, showRuntime bool, skip, max int) (n, lastN int) {
|
|
// commitFrame commits to a logical frame and returns whether this frame
|
|
// should be printed and whether iteration should stop.
|
|
commitFrame := func() (pr, stop bool) {
|
|
if skip == 0 && max == 0 {
|
|
// Stop
|
|
return false, true
|
|
}
|
|
n++
|
|
lastN++
|
|
if skip > 0 {
|
|
// Skip
|
|
skip--
|
|
return false, false
|
|
}
|
|
// Print
|
|
max--
|
|
return true, false
|
|
}
|
|
|
|
gp := u.g.ptr()
|
|
level, _, _ := gotraceback()
|
|
var cgoBuf [32]uintptr
|
|
for ; u.valid(); u.next() {
|
|
lastN = 0
|
|
f := u.frame.fn
|
|
for iu, uf := newInlineUnwinder(f, u.symPC()); uf.valid(); uf = iu.next(uf) {
|
|
sf := iu.srcFunc(uf)
|
|
callee := u.calleeFuncID
|
|
u.calleeFuncID = sf.funcID
|
|
if !(showRuntime || showframe(sf, gp, n == 0, callee)) {
|
|
continue
|
|
}
|
|
|
|
if pr, stop := commitFrame(); stop {
|
|
return
|
|
} else if !pr {
|
|
continue
|
|
}
|
|
|
|
name := sf.name()
|
|
file, line := iu.fileLine(uf)
|
|
// Print during crash.
|
|
// main(0x1, 0x2, 0x3)
|
|
// /home/rsc/go/src/runtime/x.go:23 +0xf
|
|
//
|
|
printFuncName(name)
|
|
print("(")
|
|
if iu.isInlined(uf) {
|
|
print("...")
|
|
} else {
|
|
argp := unsafe.Pointer(u.frame.argp)
|
|
printArgs(f, argp, u.symPC())
|
|
}
|
|
print(")\n")
|
|
print("\t", file, ":", line)
|
|
if !iu.isInlined(uf) {
|
|
if u.frame.pc > f.entry() {
|
|
print(" +", hex(u.frame.pc-f.entry()))
|
|
}
|
|
if gp.m != nil && gp.m.throwing >= throwTypeRuntime && gp == gp.m.curg || level >= 2 {
|
|
print(" fp=", hex(u.frame.fp), " sp=", hex(u.frame.sp), " pc=", hex(u.frame.pc))
|
|
}
|
|
}
|
|
print("\n")
|
|
}
|
|
|
|
// Print cgo frames.
|
|
if cgoN := u.cgoCallers(cgoBuf[:]); cgoN > 0 {
|
|
var arg cgoSymbolizerArg
|
|
anySymbolized := false
|
|
stop := false
|
|
for _, pc := range cgoBuf[:cgoN] {
|
|
if cgoSymbolizer == nil {
|
|
if pr, stop := commitFrame(); stop {
|
|
break
|
|
} else if pr {
|
|
print("non-Go function at pc=", hex(pc), "\n")
|
|
}
|
|
} else {
|
|
stop = printOneCgoTraceback(pc, commitFrame, &arg)
|
|
anySymbolized = true
|
|
if stop {
|
|
break
|
|
}
|
|
}
|
|
}
|
|
if anySymbolized {
|
|
// Free symbolization state.
|
|
arg.pc = 0
|
|
callCgoSymbolizer(&arg)
|
|
}
|
|
if stop {
|
|
return
|
|
}
|
|
}
|
|
}
|
|
return n, 0
|
|
}
|
|
|
|
// printAncestorTraceback prints the traceback of the given ancestor.
|
|
// TODO: Unify this with gentraceback and CallersFrames.
|
|
func printAncestorTraceback(ancestor ancestorInfo) {
|
|
print("[originating from goroutine ", ancestor.goid, "]:\n")
|
|
for fidx, pc := range ancestor.pcs {
|
|
f := findfunc(pc) // f previously validated
|
|
if showfuncinfo(f.srcFunc(), fidx == 0, abi.FuncIDNormal) {
|
|
printAncestorTracebackFuncInfo(f, pc)
|
|
}
|
|
}
|
|
if len(ancestor.pcs) == tracebackInnerFrames {
|
|
print("...additional frames elided...\n")
|
|
}
|
|
// Show what created goroutine, except main goroutine (goid 1).
|
|
f := findfunc(ancestor.gopc)
|
|
if f.valid() && showfuncinfo(f.srcFunc(), false, abi.FuncIDNormal) && ancestor.goid != 1 {
|
|
// In ancestor mode, we'll already print the goroutine ancestor.
|
|
// Pass 0 for the goid parameter so we don't print it again.
|
|
printcreatedby1(f, ancestor.gopc, 0)
|
|
}
|
|
}
|
|
|
|
// printAncestorTracebackFuncInfo prints the given function info at a given pc
|
|
// within an ancestor traceback. The precision of this info is reduced
|
|
// due to only have access to the pcs at the time of the caller
|
|
// goroutine being created.
|
|
func printAncestorTracebackFuncInfo(f funcInfo, pc uintptr) {
|
|
u, uf := newInlineUnwinder(f, pc)
|
|
file, line := u.fileLine(uf)
|
|
printFuncName(u.srcFunc(uf).name())
|
|
print("(...)\n")
|
|
print("\t", file, ":", line)
|
|
if pc > f.entry() {
|
|
print(" +", hex(pc-f.entry()))
|
|
}
|
|
print("\n")
|
|
}
|
|
|
|
func callers(skip int, pcbuf []uintptr) int {
|
|
sp := getcallersp()
|
|
pc := getcallerpc()
|
|
gp := getg()
|
|
var n int
|
|
systemstack(func() {
|
|
var u unwinder
|
|
u.initAt(pc, sp, 0, gp, unwindSilentErrors)
|
|
n = tracebackPCs(&u, skip, pcbuf)
|
|
})
|
|
return n
|
|
}
|
|
|
|
func gcallers(gp *g, skip int, pcbuf []uintptr) int {
|
|
var u unwinder
|
|
u.init(gp, unwindSilentErrors)
|
|
return tracebackPCs(&u, skip, pcbuf)
|
|
}
|
|
|
|
// showframe reports whether the frame with the given characteristics should
|
|
// be printed during a traceback.
|
|
func showframe(sf srcFunc, gp *g, firstFrame bool, calleeID abi.FuncID) bool {
|
|
mp := getg().m
|
|
if mp.throwing >= throwTypeRuntime && gp != nil && (gp == mp.curg || gp == mp.caughtsig.ptr()) {
|
|
return true
|
|
}
|
|
return showfuncinfo(sf, firstFrame, calleeID)
|
|
}
|
|
|
|
// showfuncinfo reports whether a function with the given characteristics should
|
|
// be printed during a traceback.
|
|
func showfuncinfo(sf srcFunc, firstFrame bool, calleeID abi.FuncID) bool {
|
|
level, _, _ := gotraceback()
|
|
if level > 1 {
|
|
// Show all frames.
|
|
return true
|
|
}
|
|
|
|
if sf.funcID == abi.FuncIDWrapper && elideWrapperCalling(calleeID) {
|
|
return false
|
|
}
|
|
|
|
name := sf.name()
|
|
|
|
// Special case: always show runtime.gopanic frame
|
|
// in the middle of a stack trace, so that we can
|
|
// see the boundary between ordinary code and
|
|
// panic-induced deferred code.
|
|
// See golang.org/issue/5832.
|
|
if name == "runtime.gopanic" && !firstFrame {
|
|
return true
|
|
}
|
|
|
|
return bytealg.IndexByteString(name, '.') >= 0 && (!stringslite.HasPrefix(name, "runtime.") || isExportedRuntime(name))
|
|
}
|
|
|
|
// isExportedRuntime reports whether name is an exported runtime function.
|
|
// It is only for runtime functions, so ASCII A-Z is fine.
|
|
func isExportedRuntime(name string) bool {
|
|
// Check and remove package qualifier.
|
|
n := len("runtime.")
|
|
if len(name) <= n || name[:n] != "runtime." {
|
|
return false
|
|
}
|
|
name = name[n:]
|
|
rcvr := ""
|
|
|
|
// Extract receiver type, if any.
|
|
// For example, runtime.(*Func).Entry
|
|
i := len(name) - 1
|
|
for i >= 0 && name[i] != '.' {
|
|
i--
|
|
}
|
|
if i >= 0 {
|
|
rcvr = name[:i]
|
|
name = name[i+1:]
|
|
// Remove parentheses and star for pointer receivers.
|
|
if len(rcvr) >= 3 && rcvr[0] == '(' && rcvr[1] == '*' && rcvr[len(rcvr)-1] == ')' {
|
|
rcvr = rcvr[2 : len(rcvr)-1]
|
|
}
|
|
}
|
|
|
|
// Exported functions and exported methods on exported types.
|
|
return len(name) > 0 && 'A' <= name[0] && name[0] <= 'Z' && (len(rcvr) == 0 || 'A' <= rcvr[0] && rcvr[0] <= 'Z')
|
|
}
|
|
|
|
// elideWrapperCalling reports whether a wrapper function that called
|
|
// function id should be elided from stack traces.
|
|
func elideWrapperCalling(id abi.FuncID) bool {
|
|
// If the wrapper called a panic function instead of the
|
|
// wrapped function, we want to include it in stacks.
|
|
return !(id == abi.FuncID_gopanic || id == abi.FuncID_sigpanic || id == abi.FuncID_panicwrap)
|
|
}
|
|
|
|
var gStatusStrings = [...]string{
|
|
_Gidle: "idle",
|
|
_Grunnable: "runnable",
|
|
_Grunning: "running",
|
|
_Gsyscall: "syscall",
|
|
_Gwaiting: "waiting",
|
|
_Gdead: "dead",
|
|
_Gcopystack: "copystack",
|
|
_Gpreempted: "preempted",
|
|
}
|
|
|
|
func goroutineheader(gp *g) {
|
|
level, _, _ := gotraceback()
|
|
|
|
gpstatus := readgstatus(gp)
|
|
|
|
isScan := gpstatus&_Gscan != 0
|
|
gpstatus &^= _Gscan // drop the scan bit
|
|
|
|
// Basic string status
|
|
var status string
|
|
if 0 <= gpstatus && gpstatus < uint32(len(gStatusStrings)) {
|
|
status = gStatusStrings[gpstatus]
|
|
} else {
|
|
status = "???"
|
|
}
|
|
|
|
// Override.
|
|
if gpstatus == _Gwaiting && gp.waitreason != waitReasonZero {
|
|
status = gp.waitreason.String()
|
|
}
|
|
|
|
// approx time the G is blocked, in minutes
|
|
var waitfor int64
|
|
if (gpstatus == _Gwaiting || gpstatus == _Gsyscall) && gp.waitsince != 0 {
|
|
waitfor = (nanotime() - gp.waitsince) / 60e9
|
|
}
|
|
print("goroutine ", gp.goid)
|
|
if gp.m != nil && gp.m.throwing >= throwTypeRuntime && gp == gp.m.curg || level >= 2 {
|
|
print(" gp=", gp)
|
|
if gp.m != nil {
|
|
print(" m=", gp.m.id, " mp=", gp.m)
|
|
} else {
|
|
print(" m=nil")
|
|
}
|
|
}
|
|
print(" [", status)
|
|
if isScan {
|
|
print(" (scan)")
|
|
}
|
|
if waitfor >= 1 {
|
|
print(", ", waitfor, " minutes")
|
|
}
|
|
if gp.lockedm != 0 {
|
|
print(", locked to thread")
|
|
}
|
|
print("]:\n")
|
|
}
|
|
|
|
func tracebackothers(me *g) {
|
|
level, _, _ := gotraceback()
|
|
|
|
// Show the current goroutine first, if we haven't already.
|
|
curgp := getg().m.curg
|
|
if curgp != nil && curgp != me {
|
|
print("\n")
|
|
goroutineheader(curgp)
|
|
traceback(^uintptr(0), ^uintptr(0), 0, curgp)
|
|
}
|
|
|
|
// We can't call locking forEachG here because this may be during fatal
|
|
// throw/panic, where locking could be out-of-order or a direct
|
|
// deadlock.
|
|
//
|
|
// Instead, use forEachGRace, which requires no locking. We don't lock
|
|
// against concurrent creation of new Gs, but even with allglock we may
|
|
// miss Gs created after this loop.
|
|
forEachGRace(func(gp *g) {
|
|
if gp == me || gp == curgp || readgstatus(gp) == _Gdead || isSystemGoroutine(gp, false) && level < 2 {
|
|
return
|
|
}
|
|
print("\n")
|
|
goroutineheader(gp)
|
|
// Note: gp.m == getg().m occurs when tracebackothers is called
|
|
// from a signal handler initiated during a systemstack call.
|
|
// The original G is still in the running state, and we want to
|
|
// print its stack.
|
|
if gp.m != getg().m && readgstatus(gp)&^_Gscan == _Grunning {
|
|
print("\tgoroutine running on other thread; stack unavailable\n")
|
|
printcreatedby(gp)
|
|
} else {
|
|
traceback(^uintptr(0), ^uintptr(0), 0, gp)
|
|
}
|
|
})
|
|
}
|
|
|
|
// tracebackHexdump hexdumps part of stk around frame.sp and frame.fp
|
|
// for debugging purposes. If the address bad is included in the
|
|
// hexdumped range, it will mark it as well.
|
|
func tracebackHexdump(stk stack, frame *stkframe, bad uintptr) {
|
|
const expand = 32 * goarch.PtrSize
|
|
const maxExpand = 256 * goarch.PtrSize
|
|
// Start around frame.sp.
|
|
lo, hi := frame.sp, frame.sp
|
|
// Expand to include frame.fp.
|
|
if frame.fp != 0 && frame.fp < lo {
|
|
lo = frame.fp
|
|
}
|
|
if frame.fp != 0 && frame.fp > hi {
|
|
hi = frame.fp
|
|
}
|
|
// Expand a bit more.
|
|
lo, hi = lo-expand, hi+expand
|
|
// But don't go too far from frame.sp.
|
|
if lo < frame.sp-maxExpand {
|
|
lo = frame.sp - maxExpand
|
|
}
|
|
if hi > frame.sp+maxExpand {
|
|
hi = frame.sp + maxExpand
|
|
}
|
|
// And don't go outside the stack bounds.
|
|
if lo < stk.lo {
|
|
lo = stk.lo
|
|
}
|
|
if hi > stk.hi {
|
|
hi = stk.hi
|
|
}
|
|
|
|
// Print the hex dump.
|
|
print("stack: frame={sp:", hex(frame.sp), ", fp:", hex(frame.fp), "} stack=[", hex(stk.lo), ",", hex(stk.hi), ")\n")
|
|
hexdumpWords(lo, hi, func(p uintptr) byte {
|
|
switch p {
|
|
case frame.fp:
|
|
return '>'
|
|
case frame.sp:
|
|
return '<'
|
|
case bad:
|
|
return '!'
|
|
}
|
|
return 0
|
|
})
|
|
}
|
|
|
|
// isSystemGoroutine reports whether the goroutine g must be omitted
|
|
// in stack dumps and deadlock detector. This is any goroutine that
|
|
// starts at a runtime.* entry point, except for runtime.main,
|
|
// runtime.handleAsyncEvent (wasm only) and sometimes runtime.runfinq.
|
|
//
|
|
// If fixed is true, any goroutine that can vary between user and
|
|
// system (that is, the finalizer goroutine) is considered a user
|
|
// goroutine.
|
|
func isSystemGoroutine(gp *g, fixed bool) bool {
|
|
// Keep this in sync with internal/trace.IsSystemGoroutine.
|
|
f := findfunc(gp.startpc)
|
|
if !f.valid() {
|
|
return false
|
|
}
|
|
if f.funcID == abi.FuncID_runtime_main || f.funcID == abi.FuncID_corostart || f.funcID == abi.FuncID_handleAsyncEvent {
|
|
return false
|
|
}
|
|
if f.funcID == abi.FuncID_runfinq {
|
|
// We include the finalizer goroutine if it's calling
|
|
// back into user code.
|
|
if fixed {
|
|
// This goroutine can vary. In fixed mode,
|
|
// always consider it a user goroutine.
|
|
return false
|
|
}
|
|
return fingStatus.Load()&fingRunningFinalizer == 0
|
|
}
|
|
return stringslite.HasPrefix(funcname(f), "runtime.")
|
|
}
|
|
|
|
// SetCgoTraceback records three C functions to use to gather
|
|
// traceback information from C code and to convert that traceback
|
|
// information into symbolic information. These are used when printing
|
|
// stack traces for a program that uses cgo.
|
|
//
|
|
// The traceback and context functions may be called from a signal
|
|
// handler, and must therefore use only async-signal safe functions.
|
|
// The symbolizer function may be called while the program is
|
|
// crashing, and so must be cautious about using memory. None of the
|
|
// functions may call back into Go.
|
|
//
|
|
// The context function will be called with a single argument, a
|
|
// pointer to a struct:
|
|
//
|
|
// struct {
|
|
// Context uintptr
|
|
// }
|
|
//
|
|
// In C syntax, this struct will be
|
|
//
|
|
// struct {
|
|
// uintptr_t Context;
|
|
// };
|
|
//
|
|
// If the Context field is 0, the context function is being called to
|
|
// record the current traceback context. It should record in the
|
|
// Context field whatever information is needed about the current
|
|
// point of execution to later produce a stack trace, probably the
|
|
// stack pointer and PC. In this case the context function will be
|
|
// called from C code.
|
|
//
|
|
// If the Context field is not 0, then it is a value returned by a
|
|
// previous call to the context function. This case is called when the
|
|
// context is no longer needed; that is, when the Go code is returning
|
|
// to its C code caller. This permits the context function to release
|
|
// any associated resources.
|
|
//
|
|
// While it would be correct for the context function to record a
|
|
// complete a stack trace whenever it is called, and simply copy that
|
|
// out in the traceback function, in a typical program the context
|
|
// function will be called many times without ever recording a
|
|
// traceback for that context. Recording a complete stack trace in a
|
|
// call to the context function is likely to be inefficient.
|
|
//
|
|
// The traceback function will be called with a single argument, a
|
|
// pointer to a struct:
|
|
//
|
|
// struct {
|
|
// Context uintptr
|
|
// SigContext uintptr
|
|
// Buf *uintptr
|
|
// Max uintptr
|
|
// }
|
|
//
|
|
// In C syntax, this struct will be
|
|
//
|
|
// struct {
|
|
// uintptr_t Context;
|
|
// uintptr_t SigContext;
|
|
// uintptr_t* Buf;
|
|
// uintptr_t Max;
|
|
// };
|
|
//
|
|
// The Context field will be zero to gather a traceback from the
|
|
// current program execution point. In this case, the traceback
|
|
// function will be called from C code.
|
|
//
|
|
// Otherwise Context will be a value previously returned by a call to
|
|
// the context function. The traceback function should gather a stack
|
|
// trace from that saved point in the program execution. The traceback
|
|
// function may be called from an execution thread other than the one
|
|
// that recorded the context, but only when the context is known to be
|
|
// valid and unchanging. The traceback function may also be called
|
|
// deeper in the call stack on the same thread that recorded the
|
|
// context. The traceback function may be called multiple times with
|
|
// the same Context value; it will usually be appropriate to cache the
|
|
// result, if possible, the first time this is called for a specific
|
|
// context value.
|
|
//
|
|
// If the traceback function is called from a signal handler on a Unix
|
|
// system, SigContext will be the signal context argument passed to
|
|
// the signal handler (a C ucontext_t* cast to uintptr_t). This may be
|
|
// used to start tracing at the point where the signal occurred. If
|
|
// the traceback function is not called from a signal handler,
|
|
// SigContext will be zero.
|
|
//
|
|
// Buf is where the traceback information should be stored. It should
|
|
// be PC values, such that Buf[0] is the PC of the caller, Buf[1] is
|
|
// the PC of that function's caller, and so on. Max is the maximum
|
|
// number of entries to store. The function should store a zero to
|
|
// indicate the top of the stack, or that the caller is on a different
|
|
// stack, presumably a Go stack.
|
|
//
|
|
// Unlike runtime.Callers, the PC values returned should, when passed
|
|
// to the symbolizer function, return the file/line of the call
|
|
// instruction. No additional subtraction is required or appropriate.
|
|
//
|
|
// On all platforms, the traceback function is invoked when a call from
|
|
// Go to C to Go requests a stack trace. On linux/amd64, linux/ppc64le,
|
|
// linux/arm64, and freebsd/amd64, the traceback function is also invoked
|
|
// when a signal is received by a thread that is executing a cgo call.
|
|
// The traceback function should not make assumptions about when it is
|
|
// called, as future versions of Go may make additional calls.
|
|
//
|
|
// The symbolizer function will be called with a single argument, a
|
|
// pointer to a struct:
|
|
//
|
|
// struct {
|
|
// PC uintptr // program counter to fetch information for
|
|
// File *byte // file name (NUL terminated)
|
|
// Lineno uintptr // line number
|
|
// Func *byte // function name (NUL terminated)
|
|
// Entry uintptr // function entry point
|
|
// More uintptr // set non-zero if more info for this PC
|
|
// Data uintptr // unused by runtime, available for function
|
|
// }
|
|
//
|
|
// In C syntax, this struct will be
|
|
//
|
|
// struct {
|
|
// uintptr_t PC;
|
|
// char* File;
|
|
// uintptr_t Lineno;
|
|
// char* Func;
|
|
// uintptr_t Entry;
|
|
// uintptr_t More;
|
|
// uintptr_t Data;
|
|
// };
|
|
//
|
|
// The PC field will be a value returned by a call to the traceback
|
|
// function.
|
|
//
|
|
// The first time the function is called for a particular traceback,
|
|
// all the fields except PC will be 0. The function should fill in the
|
|
// other fields if possible, setting them to 0/nil if the information
|
|
// is not available. The Data field may be used to store any useful
|
|
// information across calls. The More field should be set to non-zero
|
|
// if there is more information for this PC, zero otherwise. If More
|
|
// is set non-zero, the function will be called again with the same
|
|
// PC, and may return different information (this is intended for use
|
|
// with inlined functions). If More is zero, the function will be
|
|
// called with the next PC value in the traceback. When the traceback
|
|
// is complete, the function will be called once more with PC set to
|
|
// zero; this may be used to free any information. Each call will
|
|
// leave the fields of the struct set to the same values they had upon
|
|
// return, except for the PC field when the More field is zero. The
|
|
// function must not keep a copy of the struct pointer between calls.
|
|
//
|
|
// When calling SetCgoTraceback, the version argument is the version
|
|
// number of the structs that the functions expect to receive.
|
|
// Currently this must be zero.
|
|
//
|
|
// The symbolizer function may be nil, in which case the results of
|
|
// the traceback function will be displayed as numbers. If the
|
|
// traceback function is nil, the symbolizer function will never be
|
|
// called. The context function may be nil, in which case the
|
|
// traceback function will only be called with the context field set
|
|
// to zero. If the context function is nil, then calls from Go to C
|
|
// to Go will not show a traceback for the C portion of the call stack.
|
|
//
|
|
// SetCgoTraceback should be called only once, ideally from an init function.
|
|
func SetCgoTraceback(version int, traceback, context, symbolizer unsafe.Pointer) {
|
|
if version != 0 {
|
|
panic("unsupported version")
|
|
}
|
|
|
|
if cgoTraceback != nil && cgoTraceback != traceback ||
|
|
cgoContext != nil && cgoContext != context ||
|
|
cgoSymbolizer != nil && cgoSymbolizer != symbolizer {
|
|
panic("call SetCgoTraceback only once")
|
|
}
|
|
|
|
cgoTraceback = traceback
|
|
cgoContext = context
|
|
cgoSymbolizer = symbolizer
|
|
|
|
// The context function is called when a C function calls a Go
|
|
// function. As such it is only called by C code in runtime/cgo.
|
|
if _cgo_set_context_function != nil {
|
|
cgocall(_cgo_set_context_function, context)
|
|
}
|
|
}
|
|
|
|
var cgoTraceback unsafe.Pointer
|
|
var cgoContext unsafe.Pointer
|
|
var cgoSymbolizer unsafe.Pointer
|
|
|
|
// cgoTracebackArg is the type passed to cgoTraceback.
|
|
type cgoTracebackArg struct {
|
|
context uintptr
|
|
sigContext uintptr
|
|
buf *uintptr
|
|
max uintptr
|
|
}
|
|
|
|
// cgoContextArg is the type passed to the context function.
|
|
type cgoContextArg struct {
|
|
context uintptr
|
|
}
|
|
|
|
// cgoSymbolizerArg is the type passed to cgoSymbolizer.
|
|
type cgoSymbolizerArg struct {
|
|
pc uintptr
|
|
file *byte
|
|
lineno uintptr
|
|
funcName *byte
|
|
entry uintptr
|
|
more uintptr
|
|
data uintptr
|
|
}
|
|
|
|
// printCgoTraceback prints a traceback of callers.
|
|
func printCgoTraceback(callers *cgoCallers) {
|
|
if cgoSymbolizer == nil {
|
|
for _, c := range callers {
|
|
if c == 0 {
|
|
break
|
|
}
|
|
print("non-Go function at pc=", hex(c), "\n")
|
|
}
|
|
return
|
|
}
|
|
|
|
commitFrame := func() (pr, stop bool) { return true, false }
|
|
var arg cgoSymbolizerArg
|
|
for _, c := range callers {
|
|
if c == 0 {
|
|
break
|
|
}
|
|
printOneCgoTraceback(c, commitFrame, &arg)
|
|
}
|
|
arg.pc = 0
|
|
callCgoSymbolizer(&arg)
|
|
}
|
|
|
|
// printOneCgoTraceback prints the traceback of a single cgo caller.
|
|
// This can print more than one line because of inlining.
|
|
// It returns the "stop" result of commitFrame.
|
|
func printOneCgoTraceback(pc uintptr, commitFrame func() (pr, stop bool), arg *cgoSymbolizerArg) bool {
|
|
arg.pc = pc
|
|
for {
|
|
if pr, stop := commitFrame(); stop {
|
|
return true
|
|
} else if !pr {
|
|
continue
|
|
}
|
|
|
|
callCgoSymbolizer(arg)
|
|
if arg.funcName != nil {
|
|
// Note that we don't print any argument
|
|
// information here, not even parentheses.
|
|
// The symbolizer must add that if appropriate.
|
|
println(gostringnocopy(arg.funcName))
|
|
} else {
|
|
println("non-Go function")
|
|
}
|
|
print("\t")
|
|
if arg.file != nil {
|
|
print(gostringnocopy(arg.file), ":", arg.lineno, " ")
|
|
}
|
|
print("pc=", hex(pc), "\n")
|
|
if arg.more == 0 {
|
|
return false
|
|
}
|
|
}
|
|
}
|
|
|
|
// callCgoSymbolizer calls the cgoSymbolizer function.
|
|
func callCgoSymbolizer(arg *cgoSymbolizerArg) {
|
|
call := cgocall
|
|
if panicking.Load() > 0 || getg().m.curg != getg() {
|
|
// We do not want to call into the scheduler when panicking
|
|
// or when on the system stack.
|
|
call = asmcgocall
|
|
}
|
|
if msanenabled {
|
|
msanwrite(unsafe.Pointer(arg), unsafe.Sizeof(cgoSymbolizerArg{}))
|
|
}
|
|
if asanenabled {
|
|
asanwrite(unsafe.Pointer(arg), unsafe.Sizeof(cgoSymbolizerArg{}))
|
|
}
|
|
call(cgoSymbolizer, noescape(unsafe.Pointer(arg)))
|
|
}
|
|
|
|
// cgoContextPCs gets the PC values from a cgo traceback.
|
|
func cgoContextPCs(ctxt uintptr, buf []uintptr) {
|
|
if cgoTraceback == nil {
|
|
return
|
|
}
|
|
call := cgocall
|
|
if panicking.Load() > 0 || getg().m.curg != getg() {
|
|
// We do not want to call into the scheduler when panicking
|
|
// or when on the system stack.
|
|
call = asmcgocall
|
|
}
|
|
arg := cgoTracebackArg{
|
|
context: ctxt,
|
|
buf: (*uintptr)(noescape(unsafe.Pointer(&buf[0]))),
|
|
max: uintptr(len(buf)),
|
|
}
|
|
if msanenabled {
|
|
msanwrite(unsafe.Pointer(&arg), unsafe.Sizeof(arg))
|
|
}
|
|
if asanenabled {
|
|
asanwrite(unsafe.Pointer(&arg), unsafe.Sizeof(arg))
|
|
}
|
|
call(cgoTraceback, noescape(unsafe.Pointer(&arg)))
|
|
}
|