Revert "runtime: make stack traces of endless recursion print only top and bottom 50"
This reverts commit 3a81338622eb5c8b94f11001855e2a68a9e36bed.
Reason for revert: Some edge cases not properly covered due to changes within runtime traceback generation since 2017, that need to be examined. This change landed very late in the Go1.16 cycle.
Change-Id: I8cf6f46ea0ef6161d878e79943e6c7cdac94bccf
Reviewed-on: https://go-review.googlesource.com/c/go/+/268577
Trust: Emmanuel Odeke <emmanuel@orijtech.com>
Run-TryBot: Emmanuel Odeke <emmanuel@orijtech.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
diff --git a/src/runtime/crash_test.go b/src/runtime/crash_test.go
index 66822e5..5e22b75 100644
--- a/src/runtime/crash_test.go
+++ b/src/runtime/crash_test.go
@@ -240,132 +240,6 @@
}
}
-func TestStackOverflowTopAndBottomTraces(t *testing.T) {
- output := runTestProg(t, "testprog", "StackOverflowTopAndBottomTraces")
-
- // 1. First things first, we expect to traverse from
- // runtime: goroutine stack exceeds 10000-byte limit
- // and down to the very end until we see:
- // runtime.goexit()
- mustHaves := []string{
- // Top half expectations
- "\\s*runtime: goroutine stack exceeds 10000-byte limit\n",
- "\\s*fatal error: stack overflow\n",
- "\\s*runtime stack:\n",
- "\\s*runtime.throw[^\n]+\n\t.+:\\d+ [^\n]+",
- "\\s+runtime\\.newstack[^\n]+\n\t.+:\\d+ [^\n]+",
- "\\s+runtime.morestack[^\n]+\n\t.+:\\d+ [^\n]+",
- "\\s+goroutine 1 \\[running\\]:",
-
- // Bottom half expectations
- "\\s*main.main\\(\\)\n",
- "\\s*runtime.main\\(\\)\n",
- "\\s*runtime.goexit\\(\\)\n",
- }
-
- for _, pat := range mustHaves {
- reg := regexp.MustCompile(pat)
- match := reg.FindAllString(output, -1)
- if len(match) == 0 {
- t.Errorf("Failed to find pattern %q", pat)
- }
- }
-
- // 2. Split top and bottom halves by the "... ({n} stack frames omitted)" message
- regHalving := regexp.MustCompile("\\.{3} \\(\\d+ stack frames omitted\\)")
- halverMatches := regHalving.FindAllString(output, -1)
- if len(halverMatches) != 1 {
- t.Fatal("Failed to find the `stack frames omitted` pattern")
- }
- str := string(output)
- halver := halverMatches[0]
- midIndex := strings.Index(str, halver)
- topHalf, bottomHalf := str[:midIndex], str[midIndex+len(halver):]
- // 2.1. Sanity check, len(topHalf) >= halver || len(bottomHalf) >= halver
- if len(topHalf) < len(halver) || len(bottomHalf) < len(halver) {
- t.Fatalf("Sanity check len(topHalf) = %d len(bottomHalf) = %d; both must be >= len(halver) %d",
- len(topHalf), len(bottomHalf), len(halver))
- }
-
- // 3. In each of the halves, we should have an equal number
- // of stacktraces before and after the "omitted frames" message.
- regStackTraces := regexp.MustCompile("\n[^\n]+\n\t.+:\\d+ .+ fp=0x.+ sp=0x.+ pc=0x.+")
- topHalfStackTraces := regStackTraces.FindAllString(topHalf, -1)
- bottomHalfStackTraces := regStackTraces.FindAllString(bottomHalf, -1)
- nTopHalf, nBottomHalf := len(topHalfStackTraces), len(bottomHalfStackTraces)
- if nTopHalf == 0 || nBottomHalf == 0 {
- t.Fatal("Both lengths of stack-halves should be non-zero")
- }
- // The bottom half will always have the 50 non-runtime frames along with these 3 frames:
- // * main.main()
- // * "runtime.main"
- // * "runtime.goexit"
- // hence we need to decrement 3 counted lines.
- if nTopHalf != nBottomHalf-3 {
- t.Errorf("len(topHalfStackTraces)=%d len(bottomHalfStackTraces)-3=%d yet must be equal\n", nTopHalf, nBottomHalf-3)
- }
-
- // 4. Next, prune out the:
- // func...
- // line...
- // pairs in both of the halves.
- prunes := []struct {
- src *string
- matches []string
- }{
- {src: &topHalf, matches: topHalfStackTraces},
- {src: &bottomHalf, matches: bottomHalfStackTraces},
- }
-
- for _, prune := range prunes {
- str := *prune.src
- for _, match := range prune.matches {
- index := strings.Index(str, match)
- str = str[:index] + str[index+len(match):]
- }
- *prune.src = str
- }
-
- // 5. Now match and prune out the remaining patterns in the top and bottom halves.
- // We aren't touching the bottom stack since its patterns are already matched
- // by the:
- // func...
- // line...
- // pairs
- topPartPrunables := []string{
- "^\\s*runtime: goroutine stack exceeds 10000-byte limit\n",
- "\\s*fatal error: stack overflow\n",
- "\\s*runtime stack:\n",
- "\\s*runtime.throw[^\n]+\n\t.+:\\d+ [^\n]+",
- "\\s+runtime\\.newstack[^\n]+\n\t.+:\\d+ [^\n]+",
- "\\s+runtime.morestack[^\n]+\n\t.+:\\d+ [^\n]+",
- "\\s+goroutine 1 \\[running\\]:",
- }
-
- for _, pat := range topPartPrunables {
- reg := regexp.MustCompile(pat)
- matches := reg.FindAllString(topHalf, -1)
- if len(matches) == 0 {
- t.Errorf("top stack traces do not contain pattern: %q", reg)
- } else if len(matches) != 1 {
- t.Errorf("inconsistent state got %d matches want only 1", len(matches))
- } else {
- match := matches[0]
- idx := strings.Index(topHalf, match)
- topHalf = topHalf[:idx] + topHalf[idx+len(match):]
- }
- }
-
- // 6. At the end we should only be left with
- // newlines in both the top and bottom halves.
- topHalf = strings.TrimSpace(topHalf)
- bottomHalf = strings.TrimSpace(bottomHalf)
- if topHalf != "" && bottomHalf != "" {
- t.Fatalf("len(topHalf)=%d len(bottomHalf)=%d\ntopHalf=\n%s\n\nbottomHalf=\n%s",
- len(topHalf), len(bottomHalf), topHalf, bottomHalf)
- }
-}
-
func TestThreadExhaustion(t *testing.T) {
output := runTestProg(t, "testprog", "ThreadExhaustion")
want := "runtime: program exceeds 10-thread limit\nfatal error: thread exhaustion"
diff --git a/src/runtime/testdata/testprog/deadlock.go b/src/runtime/testdata/testprog/deadlock.go
index 0ee1557..105d6a5 100644
--- a/src/runtime/testdata/testprog/deadlock.go
+++ b/src/runtime/testdata/testprog/deadlock.go
@@ -20,7 +20,6 @@
register("LockedDeadlock2", LockedDeadlock2)
register("GoexitDeadlock", GoexitDeadlock)
register("StackOverflow", StackOverflow)
- register("StackOverflowTopAndBottomTraces", StackOverflowTopAndBottomTraces)
register("ThreadExhaustion", ThreadExhaustion)
register("RecursivePanic", RecursivePanic)
register("RecursivePanic2", RecursivePanic2)
@@ -86,18 +85,6 @@
f()
}
-func StackOverflowTopAndBottomTraces() {
- var fi, gi func()
- fi = func() {
- gi()
- }
- gi = func() {
- fi()
- }
- debug.SetMaxStack(10000)
- fi()
-}
-
func ThreadExhaustion() {
debug.SetMaxThreads(10)
c := make(chan int)
diff --git a/src/runtime/traceback.go b/src/runtime/traceback.go
index 389ae87..f3df152 100644
--- a/src/runtime/traceback.go
+++ b/src/runtime/traceback.go
@@ -73,34 +73,17 @@
const sizeofSkipFunction = 256
-// Generic traceback. Handles runtime stack prints (pcbuf == nil && callback == nil),
+// 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.
//
-// The skip argument counts the number of logical frames to skip rather
-// than physical frames (with inlining, a PC in pcbuf can represent multiple calls).
+// The skip argument is only valid with pcbuf != nil and counts the number
+// of logical frames to skip rather than physical frames (with inlining, a
+// PC in pcbuf can represent multiple calls). If a PC is partially skipped
+// and max > 1, pcbuf[1] will be runtime.skipPleaseUseCallersFrames+N where
+// N indicates the number of logical frames to skip in pcbuf[0].
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 {
- var op operation = traversing
- if pcbuf == nil && callback == nil {
- op = printing
- }
- n, _ := ggentraceback(pc0, sp0, lr0, gp, skip, pcbuf, max, op, callback, v, flags)
- return n
-}
-
-type operation int8
-
-const (
- traversing operation = 1 << iota
- countingframes
- printing
-)
-
-// n always returns the number of total frames <= max.
-// nregularframes is the count of non-runtime frames.
-// nregularframes is only valid if op == countingframes.
-func ggentraceback(pc0, sp0, lr0 uintptr, gp *g, skip int, pcbuf *uintptr, max int, op operation, callback func(*stkframe, unsafe.Pointer) bool, v unsafe.Pointer, flags uint) (ntotalframes, nregularframes int) {
if skip > 0 && callback != nil {
throw("gentraceback callback cannot be used with non-zero skip")
}
@@ -152,6 +135,7 @@
}
waspanic := false
cgoCtxt := gp.cgoCtxt
+ printing := pcbuf == nil && callback == nil
// If the PC is zero, it's likely a nil function call.
// Start in the caller's frame.
@@ -165,7 +149,6 @@
}
}
- printing := op == printing
f := findfunc(frame.pc)
if !f.valid() {
if callback != nil || printing {
@@ -175,14 +158,15 @@
if callback != nil {
throw("unknown pc")
}
- return 0, 0
+ return 0
}
frame.fn = f
var cache pcvalueCache
lastFuncID := funcID_normal
- for ntotalframes < max {
+ n := 0
+ for n < max {
// Typically:
// pc is the PC of the running function.
// sp is the stack pointer at that program counter.
@@ -245,7 +229,7 @@
} else {
var lrPtr uintptr
if usesLR {
- if ntotalframes == 0 && frame.sp < frame.fp || frame.lr == 0 {
+ if n == 0 && frame.sp < frame.fp || frame.lr == 0 {
lrPtr = frame.sp
frame.lr = *(*uintptr)(unsafe.Pointer(lrPtr))
}
@@ -336,15 +320,11 @@
if callback != nil {
if !callback((*stkframe)(noescape(unsafe.Pointer(&frame))), v) {
- return
+ return n
}
}
- if pcbuf == nil && skip > 0 {
- // In this case we are printing and we still need to count
- // the number of frames. See https://golang.org/issues/24628.
- skip--
- } else if pcbuf != nil {
+ if pcbuf != nil {
pc := frame.pc
// backup to CALL instruction to read inlining info (same logic as below)
tracepc := pc
@@ -359,7 +339,7 @@
// See issue 34123.
// The pc can be at function entry when the frame is initialized without
// actually running code, like runtime.mstart.
- if (ntotalframes == 0 && flags&_TraceTrap != 0) || waspanic || pc == f.entry {
+ if (n == 0 && flags&_TraceTrap != 0) || waspanic || pc == f.entry {
pc++
} else {
tracepc--
@@ -377,9 +357,9 @@
// ignore wrappers
} else if skip > 0 {
skip--
- } else if ntotalframes < max {
- (*[1 << 20]uintptr)(unsafe.Pointer(pcbuf))[ntotalframes] = pc
- ntotalframes++
+ } else if n < max {
+ (*[1 << 20]uintptr)(unsafe.Pointer(pcbuf))[n] = pc
+ n++
}
lastFuncID = inltree[ix].funcID
// Back up to an instruction in the "caller".
@@ -392,15 +372,17 @@
// Ignore wrapper functions (except when they trigger panics).
} else if skip > 0 {
skip--
- } else if ntotalframes < max {
- (*[1 << 20]uintptr)(unsafe.Pointer(pcbuf))[ntotalframes] = pc
- ntotalframes++
+ } else if n < max {
+ (*[1 << 20]uintptr)(unsafe.Pointer(pcbuf))[n] = pc
+ n++
}
lastFuncID = f.funcID
- ntotalframes-- // offset ntotalframes++ below
+ n-- // offset n++ below
}
- if printing && skip <= 0 {
+ if printing {
+ // assume skip=0 for printing.
+ //
// Never elide wrappers if we haven't printed
// any frames. And don't elide wrappers that
// called panic rather than the wrapped
@@ -408,7 +390,7 @@
// backup to CALL instruction to read inlining info (same logic as below)
tracepc := frame.pc
- if (ntotalframes > 0 || flags&_TraceTrap == 0) && frame.pc > f.entry && !waspanic {
+ if (n > 0 || flags&_TraceTrap == 0) && frame.pc > f.entry && !waspanic {
tracepc--
}
// If there is inlining info, print the inner frames.
@@ -466,14 +448,7 @@
}
lastFuncID = f.funcID
}
-
- if op == countingframes {
- name := fullfuncname(f, frame.pc)
- if len(name) < len("runtime.") || name[:len("runtime.")] != "runtime." {
- nregularframes++
- }
- }
- ntotalframes++
+ n++
if f.funcID == funcID_cgocallback && len(cgoCtxt) > 0 {
ctxt := cgoCtxt[len(cgoCtxt)-1]
@@ -483,7 +458,7 @@
// callback != nil only used when we only care
// about Go frames.
if skip == 0 && callback == nil {
- ntotalframes = tracebackCgoContext(pcbuf, printing, ctxt, ntotalframes, max)
+ n = tracebackCgoContext(pcbuf, printing, ctxt, n, max)
}
}
@@ -523,7 +498,7 @@
}
if printing {
- ntotalframes = nprint
+ n = nprint
}
// Note that panic != nil is okay here: there can be leftover panics,
@@ -566,13 +541,13 @@
// 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.
- if callback != nil && ntotalframes < max && frame.sp != gp.stktopsp {
+ 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=", ntotalframes, " max=", max, "\n")
+ print("\tstack=[", hex(gp.stack.lo), "-", hex(gp.stack.hi), "] n=", n, " max=", max, "\n")
throw("traceback did not unwind completely")
}
- return
+ return n
}
// reflectMethodValue is a partial duplicate of reflect.makeFuncImpl
@@ -737,15 +712,24 @@
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
}
-
- printtraceback(pc, sp, lr, gp, flags)
+ // 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)
+
if gp.ancestors == nil {
return
}
@@ -754,62 +738,6 @@
}
}
-// countframes traverses the current stacktrace from the top of pc0 to its bottom, excluding runtime frames.
-// If flags&_TraceRuntimeframes != 0, it'll include the number of runtime frames in the count.
-func countframes(pc0, sp0, lr0 uintptr, gp *g, flags uint) (nframes int) {
- ntotalframes, nregularframes := ggentraceback(pc0, sp0, lr0, gp, 0, nil, 1<<31-1, countingframes, nil, nil, flags)
- nframes = nregularframes
- if flags&_TraceRuntimeFrames != 0 {
- nframes = ntotalframes
- }
- return nframes
-}
-
-func printtraceback(pc, sp, lr uintptr, gp *g, flags uint) {
- // We'd like to print:
- // * top nMaxFramesPerPrint frames
- // * bottom nMaxFramesPerPrint frames.
- // See https://golang.org/issue/7181.
-
- nMaxFramesPerPrint := _TracebackMaxFrames / 2
- nTop := gentraceback(pc, sp, lr, gp, 0, nil, nMaxFramesPerPrint, nil, nil, flags)
- if nTop < nMaxFramesPerPrint {
- // The common case, in which the traceback has less than nMaxFramesPerPrint.
- // By default, omits runtime frames.
- // If nTop == 0, it means we printed nothing at all, so repeat,
- // and this time force all frames to be printed.
- if nTop == 0 && (flags&_TraceRuntimeFrames) == 0 {
- // Try again to print the frames, but this time with _TraceRuntimeFrames.
- printtraceback(pc, sp, lr, gp, flags|_TraceRuntimeFrames)
- }
- return
- }
-
- // Figure out the stack size in order to print the bottom max(nMaxFramesPerPrint) frames.
- //
- // TODO(odeke-em, iant, khr): perhaps investigate and revise the solution in
- // https://go-review.googlesource.com/c/go/+/37222/9/src/runtime/traceback.go
- // so that we'll always only need 1 stack walk, instead of 2 as in this worst case.
- nframes := countframes(pc, sp, lr, gp, flags)
-
- if nframes <= _TracebackMaxFrames {
- // In this case, we'll just print out from where we left off until the end.
- gentraceback(pc, sp, lr, gp, nMaxFramesPerPrint /* skip */, nil, 1<<31-1, nil, nil, flags)
- return
- }
-
- // Otherwise, now skip until the bottom last nMaxFramesPerPrint.
-
- // Calculate the number of stack frames to elide since we
- // are printing top and bottom each of nMaxFramesPerPrint.
- if elide := nframes - _TracebackMaxFrames; elide > 0 {
- print("\n... (")
- println(elide, "stack frames omitted)\n")
- }
- skip := nframes - nMaxFramesPerPrint
- _ = gentraceback(pc, sp, lr, gp, skip, nil, 1<<31-1 /* max int32 as the biggest frame number */, nil, nil, flags)
-}
-
// printAncestorTraceback prints the traceback of the given ancestor.
// TODO: Unify this with gentraceback and CallersFrames.
func printAncestorTraceback(ancestor ancestorInfo) {
@@ -830,9 +758,11 @@
}
}
-// fullfuncname retrieves the name for a funcInfo, but if perhaps it was inlined, it'll retrieve
-// unwind and retrieve the original name.
-func fullfuncname(f funcInfo, pc uintptr) string {
+// printAncestorTraceback 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) {
name := funcname(f)
if inldata := funcdata(f, _FUNCDATA_InlTree); inldata != nil {
inltree := (*[1 << 20]inlinedCall)(inldata)
@@ -841,15 +771,6 @@
name = funcnameFromNameoff(f, inltree[ix].func_)
}
}
- return name
-}
-
-// printAncestorTraceback 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) {
- name := fullfuncname(f, pc)
file, line := funcline(f, pc)
if name == "runtime.gopanic" {
name = "panic"
