| // Copyright 2009 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| package runtime |
| |
| import ( |
| "runtime/internal/atomic" |
| "runtime/internal/sys" |
| "unsafe" |
| ) |
| |
| // The code in this file implements stack trace walking for all architectures. |
| // The most important fact about a given architecture is whether it uses a link register. |
| // On systems with link registers, the prologue for a non-leaf function stores the |
| // incoming value of LR at the bottom of the newly allocated stack frame. |
| // On systems without link registers, the architecture pushes a return PC during |
| // the call instruction, so the return PC ends up above the stack frame. |
| // In this file, the return PC is always called LR, no matter how it was found. |
| // |
| // To date, the opposite of a link register architecture is an x86 architecture. |
| // This code may need to change if some other kind of non-link-register |
| // architecture comes along. |
| // |
| // The other important fact is the size of a pointer: on 32-bit systems the LR |
| // takes up only 4 bytes on the stack, while on 64-bit systems it takes up 8 bytes. |
| // Typically this is ptrSize. |
| // |
| // As an exception, amd64p32 has ptrSize == 4 but the CALL instruction still |
| // stores an 8-byte return PC onto the stack. To accommodate this, we use regSize |
| // as the size of the architecture-pushed return PC. |
| // |
| // usesLR is defined below in terms of minFrameSize, which is defined in |
| // arch_$GOARCH.go. ptrSize and regSize are defined in stubs.go. |
| |
| const usesLR = sys.MinFrameSize > 0 |
| |
| var ( |
| // initialized in tracebackinit |
| goexitPC uintptr |
| jmpdeferPC uintptr |
| mcallPC uintptr |
| morestackPC uintptr |
| mstartPC uintptr |
| rt0_goPC uintptr |
| sigpanicPC uintptr |
| runfinqPC uintptr |
| bgsweepPC uintptr |
| forcegchelperPC uintptr |
| timerprocPC uintptr |
| gcBgMarkWorkerPC uintptr |
| systemstack_switchPC uintptr |
| systemstackPC uintptr |
| stackBarrierPC uintptr |
| cgocallback_gofuncPC uintptr |
| |
| gogoPC uintptr |
| |
| externalthreadhandlerp uintptr // initialized elsewhere |
| ) |
| |
| func tracebackinit() { |
| // Go variable initialization happens late during runtime startup. |
| // Instead of initializing the variables above in the declarations, |
| // schedinit calls this function so that the variables are |
| // initialized and available earlier in the startup sequence. |
| goexitPC = funcPC(goexit) |
| jmpdeferPC = funcPC(jmpdefer) |
| mcallPC = funcPC(mcall) |
| morestackPC = funcPC(morestack) |
| mstartPC = funcPC(mstart) |
| rt0_goPC = funcPC(rt0_go) |
| sigpanicPC = funcPC(sigpanic) |
| runfinqPC = funcPC(runfinq) |
| bgsweepPC = funcPC(bgsweep) |
| forcegchelperPC = funcPC(forcegchelper) |
| timerprocPC = funcPC(timerproc) |
| gcBgMarkWorkerPC = funcPC(gcBgMarkWorker) |
| systemstack_switchPC = funcPC(systemstack_switch) |
| systemstackPC = funcPC(systemstack) |
| stackBarrierPC = funcPC(stackBarrier) |
| cgocallback_gofuncPC = funcPC(cgocallback_gofunc) |
| |
| // used by sigprof handler |
| gogoPC = funcPC(gogo) |
| } |
| |
| // Traceback over the deferred function calls. |
| // Report them like calls that have been invoked but not started executing yet. |
| func tracebackdefers(gp *g, callback func(*stkframe, unsafe.Pointer) bool, v unsafe.Pointer) { |
| var frame stkframe |
| for d := gp._defer; d != nil; d = d.link { |
| fn := d.fn |
| if fn == nil { |
| // Defer of nil function. Args don't matter. |
| frame.pc = 0 |
| frame.fn = nil |
| frame.argp = 0 |
| frame.arglen = 0 |
| frame.argmap = nil |
| } else { |
| frame.pc = fn.fn |
| f := findfunc(frame.pc) |
| if f == nil { |
| print("runtime: unknown pc in defer ", hex(frame.pc), "\n") |
| throw("unknown pc") |
| } |
| frame.fn = f |
| frame.argp = uintptr(deferArgs(d)) |
| frame.arglen, frame.argmap = getArgInfo(&frame, f, true, fn) |
| } |
| frame.continpc = frame.pc |
| if !callback((*stkframe)(noescape(unsafe.Pointer(&frame))), v) { |
| return |
| } |
| } |
| } |
| |
| // Generic traceback. Handles runtime stack prints (pcbuf == nil), |
| // the runtime.Callers function (pcbuf != nil), as well as the garbage |
| // collector (callback != nil). A little clunky to merge these, but avoids |
| // duplicating the code and all its subtlety. |
| func gentraceback(pc0, sp0, lr0 uintptr, gp *g, skip int, pcbuf *uintptr, max int, callback func(*stkframe, unsafe.Pointer) bool, v unsafe.Pointer, flags uint) int { |
| if goexitPC == 0 { |
| throw("gentraceback before goexitPC initialization") |
| } |
| g := getg() |
| if g == gp && g == g.m.curg { |
| // The starting sp has been passed in as a uintptr, and the caller may |
| // have other uintptr-typed stack references as well. |
| // If during one of the calls that got us here or during one of the |
| // callbacks below the stack must be grown, all these uintptr references |
| // to the stack will not be updated, and gentraceback will continue |
| // to inspect the old stack memory, which may no longer be valid. |
| // Even if all the variables were updated correctly, it is not clear that |
| // we want to expose a traceback that begins on one stack and ends |
| // on another stack. That could confuse callers quite a bit. |
| // Instead, we require that gentraceback and any other function that |
| // accepts an sp for the current goroutine (typically obtained by |
| // calling getcallersp) must not run on that goroutine's stack but |
| // instead on the g0 stack. |
| throw("gentraceback cannot trace user goroutine on its own stack") |
| } |
| level, _, _ := gotraceback() |
| |
| // Fix up returns to the stack barrier by fetching the |
| // original return PC from gp.stkbar. |
| stkbarG := gp |
| stkbar := stkbarG.stkbar[stkbarG.stkbarPos:] |
| |
| if pc0 == ^uintptr(0) && sp0 == ^uintptr(0) { // Signal to fetch saved values from gp. |
| if gp.syscallsp != 0 { |
| pc0 = gp.syscallpc |
| sp0 = gp.syscallsp |
| if usesLR { |
| lr0 = 0 |
| } |
| } else { |
| pc0 = gp.sched.pc |
| sp0 = gp.sched.sp |
| if usesLR { |
| lr0 = gp.sched.lr |
| } |
| } |
| } |
| |
| nprint := 0 |
| var frame stkframe |
| frame.pc = pc0 |
| frame.sp = sp0 |
| if usesLR { |
| frame.lr = lr0 |
| } |
| waspanic := false |
| cgoCtxt := gp.cgoCtxt |
| printing := pcbuf == nil && callback == nil |
| _defer := gp._defer |
| |
| for _defer != nil && _defer.sp == _NoArgs { |
| _defer = _defer.link |
| } |
| |
| // If the PC is zero, it's likely a nil function call. |
| // Start in the caller's frame. |
| if frame.pc == 0 { |
| if usesLR { |
| frame.pc = *(*uintptr)(unsafe.Pointer(frame.sp)) |
| frame.lr = 0 |
| } else { |
| frame.pc = uintptr(*(*sys.Uintreg)(unsafe.Pointer(frame.sp))) |
| frame.sp += sys.RegSize |
| } |
| } |
| |
| f := findfunc(frame.pc) |
| if f != nil && f.entry == stackBarrierPC { |
| // We got caught in the middle of a stack barrier |
| // (presumably by a signal), so stkbar may be |
| // inconsistent with the barriers on the stack. |
| // Simulate the completion of the barrier. |
| // |
| // On x86, SP will be exactly one word above |
| // savedLRPtr. On LR machines, SP will be above |
| // savedLRPtr by some frame size. |
| var stkbarPos uintptr |
| if len(stkbar) > 0 && stkbar[0].savedLRPtr < sp0 { |
| // stackBarrier has not incremented stkbarPos. |
| stkbarPos = gp.stkbarPos |
| } else if gp.stkbarPos > 0 && gp.stkbar[gp.stkbarPos-1].savedLRPtr < sp0 { |
| // stackBarrier has incremented stkbarPos. |
| stkbarPos = gp.stkbarPos - 1 |
| } else { |
| printlock() |
| print("runtime: failed to unwind through stackBarrier at SP ", hex(sp0), "; ") |
| gcPrintStkbars(gp, int(gp.stkbarPos)) |
| print("\n") |
| throw("inconsistent state in stackBarrier") |
| } |
| |
| frame.pc = gp.stkbar[stkbarPos].savedLRVal |
| stkbar = gp.stkbar[stkbarPos+1:] |
| f = findfunc(frame.pc) |
| } |
| if f == nil { |
| if callback != nil { |
| print("runtime: unknown pc ", hex(frame.pc), "\n") |
| throw("unknown pc") |
| } |
| return 0 |
| } |
| frame.fn = f |
| |
| var cache pcvalueCache |
| |
| n := 0 |
| for n < max { |
| // Typically: |
| // pc is the PC of the running function. |
| // sp is the stack pointer at that program counter. |
| // fp is the frame pointer (caller's stack pointer) at that program counter, or nil if unknown. |
| // stk is the stack containing sp. |
| // The caller's program counter is lr, unless lr is zero, in which case it is *(uintptr*)sp. |
| f = frame.fn |
| if f.pcsp == 0 { |
| // No frame information, must be external function, like race support. |
| // See golang.org/issue/13568. |
| break |
| } |
| |
| // Found an actual function. |
| // Derive frame pointer and link register. |
| if frame.fp == 0 { |
| // We want to jump over the systemstack switch. If we're running on the |
| // g0, this systemstack is at the top of the stack. |
| // if we're not on g0 or there's a no curg, then this is a regular call. |
| sp := frame.sp |
| if flags&_TraceJumpStack != 0 && f.entry == systemstackPC && gp == g.m.g0 && gp.m.curg != nil { |
| sp = gp.m.curg.sched.sp |
| frame.sp = sp |
| stkbarG = gp.m.curg |
| stkbar = stkbarG.stkbar[stkbarG.stkbarPos:] |
| cgoCtxt = gp.m.curg.cgoCtxt |
| } |
| frame.fp = sp + uintptr(funcspdelta(f, frame.pc, &cache)) |
| if !usesLR { |
| // On x86, call instruction pushes return PC before entering new function. |
| frame.fp += sys.RegSize |
| } |
| } |
| var flr *_func |
| if topofstack(f) { |
| frame.lr = 0 |
| flr = nil |
| } else if usesLR && f.entry == jmpdeferPC { |
| // jmpdefer modifies SP/LR/PC non-atomically. |
| // If a profiling interrupt arrives during jmpdefer, |
| // the stack unwind may see a mismatched register set |
| // and get confused. Stop if we see PC within jmpdefer |
| // to avoid that confusion. |
| // See golang.org/issue/8153. |
| if callback != nil { |
| throw("traceback_arm: found jmpdefer when tracing with callback") |
| } |
| frame.lr = 0 |
| } else { |
| var lrPtr uintptr |
| if usesLR { |
| if n == 0 && frame.sp < frame.fp || frame.lr == 0 { |
| lrPtr = frame.sp |
| frame.lr = *(*uintptr)(unsafe.Pointer(lrPtr)) |
| } |
| } else { |
| if frame.lr == 0 { |
| lrPtr = frame.fp - sys.RegSize |
| frame.lr = uintptr(*(*sys.Uintreg)(unsafe.Pointer(lrPtr))) |
| } |
| } |
| if frame.lr == stackBarrierPC { |
| // Recover original PC. |
| if len(stkbar) == 0 || stkbar[0].savedLRPtr != lrPtr { |
| print("found next stack barrier at ", hex(lrPtr), "; expected ") |
| gcPrintStkbars(stkbarG, len(stkbarG.stkbar)-len(stkbar)) |
| print("\n") |
| throw("missed stack barrier") |
| } |
| frame.lr = stkbar[0].savedLRVal |
| stkbar = stkbar[1:] |
| } |
| flr = findfunc(frame.lr) |
| if flr == nil { |
| // This happens if you get a profiling interrupt at just the wrong time. |
| // In that context it is okay to stop early. |
| // But if callback is set, we're doing a garbage collection and must |
| // get everything, so crash loudly. |
| if callback != nil { |
| print("runtime: unexpected return pc for ", funcname(f), " called from ", hex(frame.lr), "\n") |
| throw("unknown caller pc") |
| } |
| } |
| } |
| |
| frame.varp = frame.fp |
| if !usesLR { |
| // On x86, call instruction pushes return PC before entering new function. |
| frame.varp -= sys.RegSize |
| } |
| |
| // If framepointer_enabled and there's a frame, then |
| // there's a saved bp here. |
| if framepointer_enabled && GOARCH == "amd64" && frame.varp > frame.sp { |
| frame.varp -= sys.RegSize |
| } |
| |
| // Derive size of arguments. |
| // Most functions have a fixed-size argument block, |
| // so we can use metadata about the function f. |
| // Not all, though: there are some variadic functions |
| // in package runtime and reflect, and for those we use call-specific |
| // metadata recorded by f's caller. |
| if callback != nil || printing { |
| frame.argp = frame.fp + sys.MinFrameSize |
| frame.arglen, frame.argmap = getArgInfo(&frame, f, callback != nil, nil) |
| } |
| |
| // Determine frame's 'continuation PC', where it can continue. |
| // Normally this is the return address on the stack, but if sigpanic |
| // is immediately below this function on the stack, then the frame |
| // stopped executing due to a trap, and frame.pc is probably not |
| // a safe point for looking up liveness information. In this panicking case, |
| // the function either doesn't return at all (if it has no defers or if the |
| // defers do not recover) or it returns from one of the calls to |
| // deferproc a second time (if the corresponding deferred func recovers). |
| // It suffices to assume that the most recent deferproc is the one that |
| // returns; everything live at earlier deferprocs is still live at that one. |
| frame.continpc = frame.pc |
| if waspanic { |
| if _defer != nil && _defer.sp == frame.sp { |
| frame.continpc = _defer.pc |
| } else { |
| frame.continpc = 0 |
| } |
| } |
| |
| // Unwind our local defer stack past this frame. |
| for _defer != nil && (_defer.sp == frame.sp || _defer.sp == _NoArgs) { |
| _defer = _defer.link |
| } |
| |
| if skip > 0 { |
| skip-- |
| goto skipped |
| } |
| |
| if pcbuf != nil { |
| (*[1 << 20]uintptr)(unsafe.Pointer(pcbuf))[n] = frame.pc |
| } |
| if callback != nil { |
| if !callback((*stkframe)(noescape(unsafe.Pointer(&frame))), v) { |
| return n |
| } |
| } |
| if printing { |
| if (flags&_TraceRuntimeFrames) != 0 || showframe(f, gp) { |
| // Print during crash. |
| // main(0x1, 0x2, 0x3) |
| // /home/rsc/go/src/runtime/x.go:23 +0xf |
| // |
| tracepc := frame.pc // back up to CALL instruction for funcline. |
| if (n > 0 || flags&_TraceTrap == 0) && frame.pc > f.entry && !waspanic { |
| tracepc-- |
| } |
| name := funcname(f) |
| if name == "runtime.gopanic" { |
| name = "panic" |
| } |
| print(name, "(") |
| argp := (*[100]uintptr)(unsafe.Pointer(frame.argp)) |
| for i := uintptr(0); i < frame.arglen/sys.PtrSize; i++ { |
| if i >= 10 { |
| print(", ...") |
| break |
| } |
| if i != 0 { |
| print(", ") |
| } |
| print(hex(argp[i])) |
| } |
| print(")\n") |
| file, line := funcline(f, tracepc) |
| print("\t", file, ":", line) |
| if frame.pc > f.entry { |
| print(" +", hex(frame.pc-f.entry)) |
| } |
| if g.m.throwing > 0 && gp == g.m.curg || level >= 2 { |
| print(" fp=", hex(frame.fp), " sp=", hex(frame.sp)) |
| } |
| print("\n") |
| nprint++ |
| } |
| } |
| n++ |
| |
| skipped: |
| if f.entry == cgocallback_gofuncPC && len(cgoCtxt) > 0 { |
| ctxt := cgoCtxt[len(cgoCtxt)-1] |
| cgoCtxt = cgoCtxt[:len(cgoCtxt)-1] |
| |
| // skip only applies to Go frames. |
| // callback != nil only used when we only care |
| // about Go frames. |
| if skip == 0 && callback == nil { |
| n = tracebackCgoContext(pcbuf, printing, ctxt, n, max) |
| } |
| } |
| |
| waspanic = f.entry == sigpanicPC |
| |
| // Do not unwind past the bottom of the stack. |
| if flr == nil { |
| break |
| } |
| |
| // Unwind to next frame. |
| frame.fn = flr |
| frame.pc = frame.lr |
| frame.lr = 0 |
| frame.sp = frame.fp |
| frame.fp = 0 |
| frame.argmap = nil |
| |
| // On link register architectures, sighandler saves the LR on stack |
| // before faking a call to sigpanic. |
| if usesLR && waspanic { |
| x := *(*uintptr)(unsafe.Pointer(frame.sp)) |
| frame.sp += sys.MinFrameSize |
| if GOARCH == "arm64" { |
| // arm64 needs 16-byte aligned SP, always |
| frame.sp += sys.PtrSize |
| } |
| f = findfunc(frame.pc) |
| frame.fn = f |
| if f == nil { |
| frame.pc = x |
| } else if funcspdelta(f, frame.pc, &cache) == 0 { |
| frame.lr = x |
| } |
| } |
| } |
| |
| if printing { |
| n = nprint |
| } |
| |
| // If callback != nil, we're being called to gather stack information during |
| // garbage collection or stack growth. In that context, require that we used |
| // up the entire defer stack. If not, then there is a bug somewhere and the |
| // garbage collection or stack growth may not have seen the correct picture |
| // of the stack. Crash now instead of silently executing the garbage collection |
| // or stack copy incorrectly and setting up for a mysterious crash later. |
| // |
| // 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. |
| // It's okay in those situations not to use up the entire defer stack: |
| // incomplete information then is still better than nothing. |
| if callback != nil && n < max && _defer != nil { |
| if _defer != nil { |
| print("runtime: g", gp.goid, ": leftover defer sp=", hex(_defer.sp), " pc=", hex(_defer.pc), "\n") |
| } |
| for _defer = gp._defer; _defer != nil; _defer = _defer.link { |
| print("\tdefer ", _defer, " sp=", hex(_defer.sp), " pc=", hex(_defer.pc), "\n") |
| } |
| throw("traceback has leftover defers") |
| } |
| |
| if callback != nil && n < max && len(stkbar) > 0 { |
| print("runtime: g", gp.goid, ": leftover stack barriers ") |
| gcPrintStkbars(stkbarG, len(stkbarG.stkbar)-len(stkbar)) |
| print("\n") |
| throw("traceback has leftover stack barriers") |
| } |
| |
| if callback != nil && n < max && frame.sp != gp.stktopsp { |
| print("runtime: g", gp.goid, ": frame.sp=", hex(frame.sp), " top=", hex(gp.stktopsp), "\n") |
| print("\tstack=[", hex(gp.stack.lo), "-", hex(gp.stack.hi), "] n=", n, " max=", max, "\n") |
| throw("traceback did not unwind completely") |
| } |
| |
| return n |
| } |
| |
| // reflectMethodValue is a partial duplicate of reflect.methodValue. |
| type reflectMethodValue struct { |
| fn uintptr |
| stack *bitvector // args bitmap |
| } |
| |
| // getArgInfo returns the argument frame information for a call to f |
| // with call frame frame. |
| // |
| // This is used for both actual calls with active stack frames and for |
| // deferred calls that are not yet executing. If this is an actual |
| // call, ctxt must be nil (getArgInfo will retrieve what it needs from |
| // the active stack frame). If this is a deferred call, ctxt must be |
| // the function object that was deferred. |
| func getArgInfo(frame *stkframe, f *_func, needArgMap bool, ctxt *funcval) (arglen uintptr, argmap *bitvector) { |
| arglen = uintptr(f.args) |
| if needArgMap && f.args == _ArgsSizeUnknown { |
| // Extract argument bitmaps for reflect stubs from the calls they made to reflect. |
| switch funcname(f) { |
| case "reflect.makeFuncStub", "reflect.methodValueCall": |
| // These take a *reflect.methodValue as their |
| // context register. |
| var mv *reflectMethodValue |
| if ctxt != nil { |
| // This is not an actual call, but a |
| // deferred call. The function value |
| // is itself the *reflect.methodValue. |
| mv = (*reflectMethodValue)(unsafe.Pointer(ctxt)) |
| } else { |
| // This is a real call that took the |
| // *reflect.methodValue as its context |
| // register and immediately saved it |
| // to 0(SP). Get the methodValue from |
| // 0(SP). |
| arg0 := frame.sp + sys.MinFrameSize |
| mv = *(**reflectMethodValue)(unsafe.Pointer(arg0)) |
| } |
| if mv.fn != f.entry { |
| print("runtime: confused by ", funcname(f), "\n") |
| throw("reflect mismatch") |
| } |
| bv := mv.stack |
| arglen = uintptr(bv.n * sys.PtrSize) |
| argmap = bv |
| } |
| } |
| return |
| } |
| |
| // tracebackCgoContext handles tracing back a cgo context value, from |
| // the context argument to setCgoTraceback, for the gentraceback |
| // function. It returns the new value of n. |
| func tracebackCgoContext(pcbuf *uintptr, printing bool, ctxt uintptr, n, max int) int { |
| var cgoPCs [32]uintptr |
| cgoContextPCs(ctxt, cgoPCs[:]) |
| var arg cgoSymbolizerArg |
| anySymbolized := false |
| for _, pc := range cgoPCs { |
| if pc == 0 || n >= max { |
| break |
| } |
| if pcbuf != nil { |
| (*[1 << 20]uintptr)(unsafe.Pointer(pcbuf))[n] = pc |
| } |
| if printing { |
| if cgoSymbolizer == nil { |
| print("non-Go function at pc=", hex(pc), "\n") |
| } else { |
| c := printOneCgoTraceback(pc, max-n, &arg) |
| n += c - 1 // +1 a few lines down |
| anySymbolized = true |
| } |
| } |
| n++ |
| } |
| if anySymbolized { |
| arg.pc = 0 |
| callCgoSymbolizer(&arg) |
| } |
| return n |
| } |
| |
| func printcreatedby(gp *g) { |
| // Show what created goroutine, except main goroutine (goid 1). |
| pc := gp.gopc |
| f := findfunc(pc) |
| if f != nil && showframe(f, gp) && gp.goid != 1 { |
| print("created by ", funcname(f), "\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.) |
| func tracebacktrap(pc, sp, lr uintptr, gp *g) { |
| traceback1(pc, sp, lr, gp, _TraceTrap) |
| } |
| |
| func traceback1(pc, sp, lr uintptr, gp *g, flags uint) { |
| // 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. |
| atomic.Store(&gp.m.cgoCallersUse, 1) |
| cgoCallers := *gp.m.cgoCallers |
| gp.m.cgoCallers[0] = 0 |
| atomic.Store(&gp.m.cgoCallersUse, 0) |
| |
| printCgoTraceback(&cgoCallers) |
| } |
| |
| var n int |
| if readgstatus(gp)&^_Gscan == _Gsyscall { |
| // Override registers if blocked in system call. |
| pc = gp.syscallpc |
| sp = gp.syscallsp |
| flags &^= _TraceTrap |
| } |
| // Print traceback. By default, omits runtime frames. |
| // If that means we print nothing at all, repeat forcing all frames printed. |
| n = gentraceback(pc, sp, lr, gp, 0, nil, _TracebackMaxFrames, nil, nil, flags) |
| if n == 0 && (flags&_TraceRuntimeFrames) == 0 { |
| n = gentraceback(pc, sp, lr, gp, 0, nil, _TracebackMaxFrames, nil, nil, flags|_TraceRuntimeFrames) |
| } |
| if n == _TracebackMaxFrames { |
| print("...additional frames elided...\n") |
| } |
| printcreatedby(gp) |
| } |
| |
| func callers(skip int, pcbuf []uintptr) int { |
| sp := getcallersp(unsafe.Pointer(&skip)) |
| pc := getcallerpc(unsafe.Pointer(&skip)) |
| gp := getg() |
| var n int |
| systemstack(func() { |
| n = gentraceback(pc, sp, 0, gp, skip, &pcbuf[0], len(pcbuf), nil, nil, 0) |
| }) |
| return n |
| } |
| |
| func gcallers(gp *g, skip int, pcbuf []uintptr) int { |
| return gentraceback(^uintptr(0), ^uintptr(0), 0, gp, skip, &pcbuf[0], len(pcbuf), nil, nil, 0) |
| } |
| |
| func showframe(f *_func, gp *g) bool { |
| g := getg() |
| if g.m.throwing > 0 && gp != nil && (gp == g.m.curg || gp == g.m.caughtsig.ptr()) { |
| return true |
| } |
| level, _, _ := gotraceback() |
| name := funcname(f) |
| |
| // Special case: always show runtime.gopanic frame, so that we can |
| // see where a panic started in the middle of a stack trace. |
| // See golang.org/issue/5832. |
| if name == "runtime.gopanic" { |
| return true |
| } |
| |
| return level > 1 || f != nil && contains(name, ".") && (!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 { |
| const n = len("runtime.") |
| return len(name) > n && name[:n] == "runtime." && 'A' <= name[n] && name[n] <= 'Z' |
| } |
| |
| var gStatusStrings = [...]string{ |
| _Gidle: "idle", |
| _Grunnable: "runnable", |
| _Grunning: "running", |
| _Gsyscall: "syscall", |
| _Gwaiting: "waiting", |
| _Gdead: "dead", |
| _Gcopystack: "copystack", |
| } |
| |
| func goroutineheader(gp *g) { |
| 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 != "" { |
| status = gp.waitreason |
| } |
| |
| // 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, " [", status) |
| if isScan { |
| print(" (scan)") |
| } |
| if waitfor >= 1 { |
| print(", ", waitfor, " minutes") |
| } |
| if gp.lockedm != nil { |
| print(", locked to thread") |
| } |
| print("]:\n") |
| } |
| |
| func tracebackothers(me *g) { |
| level, _, _ := gotraceback() |
| |
| // Show the current goroutine first, if we haven't already. |
| g := getg() |
| gp := g.m.curg |
| if gp != nil && gp != me { |
| print("\n") |
| goroutineheader(gp) |
| traceback(^uintptr(0), ^uintptr(0), 0, gp) |
| } |
| |
| lock(&allglock) |
| for _, gp := range allgs { |
| if gp == me || gp == g.m.curg || readgstatus(gp) == _Gdead || isSystemGoroutine(gp) && level < 2 { |
| continue |
| } |
| print("\n") |
| goroutineheader(gp) |
| // Note: gp.m == g.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 != g.m && readgstatus(gp)&^_Gscan == _Grunning { |
| print("\tgoroutine running on other thread; stack unavailable\n") |
| printcreatedby(gp) |
| } else { |
| traceback(^uintptr(0), ^uintptr(0), 0, gp) |
| } |
| } |
| unlock(&allglock) |
| } |
| |
| // Does f mark the top of a goroutine stack? |
| func topofstack(f *_func) bool { |
| pc := f.entry |
| return pc == goexitPC || |
| pc == mstartPC || |
| pc == mcallPC || |
| pc == morestackPC || |
| pc == rt0_goPC || |
| externalthreadhandlerp != 0 && pc == externalthreadhandlerp |
| } |
| |
| // isSystemGoroutine reports whether the goroutine g must be omitted in |
| // stack dumps and deadlock detector. |
| func isSystemGoroutine(gp *g) bool { |
| pc := gp.startpc |
| return pc == runfinqPC && !fingRunning || |
| pc == bgsweepPC || |
| pc == forcegchelperPC || |
| pc == timerprocPC || |
| pc == gcBgMarkWorkerPC |
| } |
| |
| // 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. |
| // |
| // 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 |
| } |
| |
| // cgoTraceback 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 |
| } |
| |
| var arg cgoSymbolizerArg |
| for _, c := range callers { |
| if c == 0 { |
| break |
| } |
| printOneCgoTraceback(c, 0x7fffffff, &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. |
| // Returns the number of frames printed. |
| func printOneCgoTraceback(pc uintptr, max int, arg *cgoSymbolizerArg) int { |
| c := 0 |
| arg.pc = pc |
| for { |
| if c > max { |
| break |
| } |
| 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") |
| c++ |
| if arg.more == 0 { |
| break |
| } |
| } |
| return c |
| } |
| |
| // callCgoSymbolizer calls the cgoSymbolizer function. |
| func callCgoSymbolizer(arg *cgoSymbolizerArg) { |
| call := cgocall |
| if panicking > 0 || getg().m.curg != getg() { |
| // We do not want to call into the scheduler when panicking |
| // or when on the system stack. |
| call = asmcgocall |
| } |
| 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 > 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)), |
| } |
| call(cgoTraceback, noescape(unsafe.Pointer(&arg))) |
| } |