Source file src/runtime/traceback.go
Documentation: runtime
1 // Copyright 2009 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package runtime 6 7 import ( 8 "runtime/internal/atomic" 9 "runtime/internal/sys" 10 "unsafe" 11 ) 12 13 // The code in this file implements stack trace walking for all architectures. 14 // The most important fact about a given architecture is whether it uses a link register. 15 // On systems with link registers, the prologue for a non-leaf function stores the 16 // incoming value of LR at the bottom of the newly allocated stack frame. 17 // On systems without link registers, the architecture pushes a return PC during 18 // the call instruction, so the return PC ends up above the stack frame. 19 // In this file, the return PC is always called LR, no matter how it was found. 20 // 21 // To date, the opposite of a link register architecture is an x86 architecture. 22 // This code may need to change if some other kind of non-link-register 23 // architecture comes along. 24 // 25 // The other important fact is the size of a pointer: on 32-bit systems the LR 26 // takes up only 4 bytes on the stack, while on 64-bit systems it takes up 8 bytes. 27 // Typically this is ptrSize. 28 // 29 // As an exception, amd64p32 had ptrSize == 4 but the CALL instruction still 30 // stored an 8-byte return PC onto the stack. To accommodate this, we used regSize 31 // as the size of the architecture-pushed return PC. 32 // 33 // usesLR is defined below in terms of minFrameSize, which is defined in 34 // arch_$GOARCH.go. ptrSize and regSize are defined in stubs.go. 35 36 const usesLR = sys.MinFrameSize > 0 37 38 var skipPC uintptr 39 40 func tracebackinit() { 41 // Go variable initialization happens late during runtime startup. 42 // Instead of initializing the variables above in the declarations, 43 // schedinit calls this function so that the variables are 44 // initialized and available earlier in the startup sequence. 45 skipPC = funcPC(skipPleaseUseCallersFrames) 46 } 47 48 // Traceback over the deferred function calls. 49 // Report them like calls that have been invoked but not started executing yet. 50 func tracebackdefers(gp *g, callback func(*stkframe, unsafe.Pointer) bool, v unsafe.Pointer) { 51 var frame stkframe 52 for d := gp._defer; d != nil; d = d.link { 53 fn := d.fn 54 if fn == nil { 55 // Defer of nil function. Args don't matter. 56 frame.pc = 0 57 frame.fn = funcInfo{} 58 frame.argp = 0 59 frame.arglen = 0 60 frame.argmap = nil 61 } else { 62 frame.pc = fn.fn 63 f := findfunc(frame.pc) 64 if !f.valid() { 65 print("runtime: unknown pc in defer ", hex(frame.pc), "\n") 66 throw("unknown pc") 67 } 68 frame.fn = f 69 frame.argp = uintptr(deferArgs(d)) 70 var ok bool 71 frame.arglen, frame.argmap, ok = getArgInfoFast(f, true) 72 if !ok { 73 frame.arglen, frame.argmap = getArgInfo(&frame, f, true, fn) 74 } 75 } 76 frame.continpc = frame.pc 77 if !callback((*stkframe)(noescape(unsafe.Pointer(&frame))), v) { 78 return 79 } 80 } 81 } 82 83 const sizeofSkipFunction = 256 84 85 // This function is defined in asm.s to be sizeofSkipFunction bytes long. 86 func skipPleaseUseCallersFrames() 87 88 // Generic traceback. Handles runtime stack prints (pcbuf == nil), 89 // the runtime.Callers function (pcbuf != nil), as well as the garbage 90 // collector (callback != nil). A little clunky to merge these, but avoids 91 // duplicating the code and all its subtlety. 92 // 93 // The skip argument is only valid with pcbuf != nil and counts the number 94 // of logical frames to skip rather than physical frames (with inlining, a 95 // PC in pcbuf can represent multiple calls). If a PC is partially skipped 96 // and max > 1, pcbuf[1] will be runtime.skipPleaseUseCallersFrames+N where 97 // N indicates the number of logical frames to skip in pcbuf[0]. 98 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 { 99 if skip > 0 && callback != nil { 100 throw("gentraceback callback cannot be used with non-zero skip") 101 } 102 103 // Don't call this "g"; it's too easy get "g" and "gp" confused. 104 if ourg := getg(); ourg == gp && ourg == ourg.m.curg { 105 // The starting sp has been passed in as a uintptr, and the caller may 106 // have other uintptr-typed stack references as well. 107 // If during one of the calls that got us here or during one of the 108 // callbacks below the stack must be grown, all these uintptr references 109 // to the stack will not be updated, and gentraceback will continue 110 // to inspect the old stack memory, which may no longer be valid. 111 // Even if all the variables were updated correctly, it is not clear that 112 // we want to expose a traceback that begins on one stack and ends 113 // on another stack. That could confuse callers quite a bit. 114 // Instead, we require that gentraceback and any other function that 115 // accepts an sp for the current goroutine (typically obtained by 116 // calling getcallersp) must not run on that goroutine's stack but 117 // instead on the g0 stack. 118 throw("gentraceback cannot trace user goroutine on its own stack") 119 } 120 level, _, _ := gotraceback() 121 122 var ctxt *funcval // Context pointer for unstarted goroutines. See issue #25897. 123 124 if pc0 == ^uintptr(0) && sp0 == ^uintptr(0) { // Signal to fetch saved values from gp. 125 if gp.syscallsp != 0 { 126 pc0 = gp.syscallpc 127 sp0 = gp.syscallsp 128 if usesLR { 129 lr0 = 0 130 } 131 } else { 132 pc0 = gp.sched.pc 133 sp0 = gp.sched.sp 134 if usesLR { 135 lr0 = gp.sched.lr 136 } 137 ctxt = (*funcval)(gp.sched.ctxt) 138 } 139 } 140 141 nprint := 0 142 var frame stkframe 143 frame.pc = pc0 144 frame.sp = sp0 145 if usesLR { 146 frame.lr = lr0 147 } 148 waspanic := false 149 cgoCtxt := gp.cgoCtxt 150 printing := pcbuf == nil && callback == nil 151 152 // If the PC is zero, it's likely a nil function call. 153 // Start in the caller's frame. 154 if frame.pc == 0 { 155 if usesLR { 156 frame.pc = *(*uintptr)(unsafe.Pointer(frame.sp)) 157 frame.lr = 0 158 } else { 159 frame.pc = uintptr(*(*sys.Uintreg)(unsafe.Pointer(frame.sp))) 160 frame.sp += sys.RegSize 161 } 162 } 163 164 f := findfunc(frame.pc) 165 if !f.valid() { 166 if callback != nil || printing { 167 print("runtime: unknown pc ", hex(frame.pc), "\n") 168 tracebackHexdump(gp.stack, &frame, 0) 169 } 170 if callback != nil { 171 throw("unknown pc") 172 } 173 return 0 174 } 175 frame.fn = f 176 177 var cache pcvalueCache 178 179 lastFuncID := funcID_normal 180 n := 0 181 for n < max { 182 // Typically: 183 // pc is the PC of the running function. 184 // sp is the stack pointer at that program counter. 185 // fp is the frame pointer (caller's stack pointer) at that program counter, or nil if unknown. 186 // stk is the stack containing sp. 187 // The caller's program counter is lr, unless lr is zero, in which case it is *(uintptr*)sp. 188 f = frame.fn 189 if f.pcsp == 0 { 190 // No frame information, must be external function, like race support. 191 // See golang.org/issue/13568. 192 break 193 } 194 195 // Found an actual function. 196 // Derive frame pointer and link register. 197 if frame.fp == 0 { 198 // Jump over system stack transitions. If we're on g0 and there's a user 199 // goroutine, try to jump. Otherwise this is a regular call. 200 if flags&_TraceJumpStack != 0 && gp == gp.m.g0 && gp.m.curg != nil { 201 switch f.funcID { 202 case funcID_morestack: 203 // morestack does not return normally -- newstack() 204 // gogo's to curg.sched. Match that. 205 // This keeps morestack() from showing up in the backtrace, 206 // but that makes some sense since it'll never be returned 207 // to. 208 frame.pc = gp.m.curg.sched.pc 209 frame.fn = findfunc(frame.pc) 210 f = frame.fn 211 frame.sp = gp.m.curg.sched.sp 212 cgoCtxt = gp.m.curg.cgoCtxt 213 case funcID_systemstack: 214 // systemstack returns normally, so just follow the 215 // stack transition. 216 frame.sp = gp.m.curg.sched.sp 217 cgoCtxt = gp.m.curg.cgoCtxt 218 } 219 } 220 frame.fp = frame.sp + uintptr(funcspdelta(f, frame.pc, &cache)) 221 if !usesLR { 222 // On x86, call instruction pushes return PC before entering new function. 223 frame.fp += sys.RegSize 224 } 225 } 226 var flr funcInfo 227 if topofstack(f, gp.m != nil && gp == gp.m.g0) { 228 frame.lr = 0 229 flr = funcInfo{} 230 } else if usesLR && f.funcID == funcID_jmpdefer { 231 // jmpdefer modifies SP/LR/PC non-atomically. 232 // If a profiling interrupt arrives during jmpdefer, 233 // the stack unwind may see a mismatched register set 234 // and get confused. Stop if we see PC within jmpdefer 235 // to avoid that confusion. 236 // See golang.org/issue/8153. 237 if callback != nil { 238 throw("traceback_arm: found jmpdefer when tracing with callback") 239 } 240 frame.lr = 0 241 } else { 242 var lrPtr uintptr 243 if usesLR { 244 if n == 0 && frame.sp < frame.fp || frame.lr == 0 { 245 lrPtr = frame.sp 246 frame.lr = *(*uintptr)(unsafe.Pointer(lrPtr)) 247 } 248 } else { 249 if frame.lr == 0 { 250 lrPtr = frame.fp - sys.RegSize 251 frame.lr = uintptr(*(*sys.Uintreg)(unsafe.Pointer(lrPtr))) 252 } 253 } 254 flr = findfunc(frame.lr) 255 if !flr.valid() { 256 // This happens if you get a profiling interrupt at just the wrong time. 257 // In that context it is okay to stop early. 258 // But if callback is set, we're doing a garbage collection and must 259 // get everything, so crash loudly. 260 doPrint := printing 261 if doPrint && gp.m.incgo && f.funcID == funcID_sigpanic { 262 // We can inject sigpanic 263 // calls directly into C code, 264 // in which case we'll see a C 265 // return PC. Don't complain. 266 doPrint = false 267 } 268 if callback != nil || doPrint { 269 print("runtime: unexpected return pc for ", funcname(f), " called from ", hex(frame.lr), "\n") 270 tracebackHexdump(gp.stack, &frame, lrPtr) 271 } 272 if callback != nil { 273 throw("unknown caller pc") 274 } 275 } 276 } 277 278 frame.varp = frame.fp 279 if !usesLR { 280 // On x86, call instruction pushes return PC before entering new function. 281 frame.varp -= sys.RegSize 282 } 283 284 // If framepointer_enabled and there's a frame, then 285 // there's a saved bp here. 286 if frame.varp > frame.sp && (framepointer_enabled && GOARCH == "amd64" || GOARCH == "arm64") { 287 frame.varp -= sys.RegSize 288 } 289 290 // Derive size of arguments. 291 // Most functions have a fixed-size argument block, 292 // so we can use metadata about the function f. 293 // Not all, though: there are some variadic functions 294 // in package runtime and reflect, and for those we use call-specific 295 // metadata recorded by f's caller. 296 if callback != nil || printing { 297 frame.argp = frame.fp + sys.MinFrameSize 298 var ok bool 299 frame.arglen, frame.argmap, ok = getArgInfoFast(f, callback != nil) 300 if !ok { 301 frame.arglen, frame.argmap = getArgInfo(&frame, f, callback != nil, ctxt) 302 } 303 } 304 ctxt = nil // ctxt is only needed to get arg maps for the topmost frame 305 306 // Determine frame's 'continuation PC', where it can continue. 307 // Normally this is the return address on the stack, but if sigpanic 308 // is immediately below this function on the stack, then the frame 309 // stopped executing due to a trap, and frame.pc is probably not 310 // a safe point for looking up liveness information. In this panicking case, 311 // the function either doesn't return at all (if it has no defers or if the 312 // defers do not recover) or it returns from one of the calls to 313 // deferproc a second time (if the corresponding deferred func recovers). 314 // In the latter case, use a deferreturn call site as the continuation pc. 315 frame.continpc = frame.pc 316 if waspanic { 317 if frame.fn.deferreturn != 0 { 318 frame.continpc = frame.fn.entry + uintptr(frame.fn.deferreturn) + 1 319 // Note: this may perhaps keep return variables alive longer than 320 // strictly necessary, as we are using "function has a defer statement" 321 // as a proxy for "function actually deferred something". It seems 322 // to be a minor drawback. (We used to actually look through the 323 // gp._defer for a defer corresponding to this function, but that 324 // is hard to do with defer records on the stack during a stack copy.) 325 // Note: the +1 is to offset the -1 that 326 // stack.go:getStackMap does to back up a return 327 // address make sure the pc is in the CALL instruction. 328 } else { 329 frame.continpc = 0 330 } 331 } 332 333 if callback != nil { 334 if !callback((*stkframe)(noescape(unsafe.Pointer(&frame))), v) { 335 return n 336 } 337 } 338 339 if pcbuf != nil { 340 pc := frame.pc 341 // backup to CALL instruction to read inlining info (same logic as below) 342 tracepc := pc 343 // Normally, pc is a return address. In that case, we want to look up 344 // file/line information using pc-1, because that is the pc of the 345 // call instruction (more precisely, the last byte of the call instruction). 346 // Callers expect the pc buffer to contain return addresses and do the 347 // same -1 themselves, so we keep pc unchanged. 348 // When the pc is from a signal (e.g. profiler or segv) then we want 349 // to look up file/line information using pc, and we store pc+1 in the 350 // pc buffer so callers can unconditionally subtract 1 before looking up. 351 // See issue 34123. 352 // The pc can be at function entry when the frame is initialized without 353 // actually running code, like runtime.mstart. 354 if (n == 0 && flags&_TraceTrap != 0) || waspanic || pc == f.entry { 355 pc++ 356 } else { 357 tracepc-- 358 } 359 360 // If there is inlining info, record the inner frames. 361 if inldata := funcdata(f, _FUNCDATA_InlTree); inldata != nil { 362 inltree := (*[1 << 20]inlinedCall)(inldata) 363 for { 364 ix := pcdatavalue(f, _PCDATA_InlTreeIndex, tracepc, &cache) 365 if ix < 0 { 366 break 367 } 368 if inltree[ix].funcID == funcID_wrapper && elideWrapperCalling(lastFuncID) { 369 // ignore wrappers 370 } else if skip > 0 { 371 skip-- 372 } else if n < max { 373 (*[1 << 20]uintptr)(unsafe.Pointer(pcbuf))[n] = pc 374 n++ 375 } 376 lastFuncID = inltree[ix].funcID 377 // Back up to an instruction in the "caller". 378 tracepc = frame.fn.entry + uintptr(inltree[ix].parentPc) 379 pc = tracepc + 1 380 } 381 } 382 // Record the main frame. 383 if f.funcID == funcID_wrapper && elideWrapperCalling(lastFuncID) { 384 // Ignore wrapper functions (except when they trigger panics). 385 } else if skip > 0 { 386 skip-- 387 } else if n < max { 388 (*[1 << 20]uintptr)(unsafe.Pointer(pcbuf))[n] = pc 389 n++ 390 } 391 lastFuncID = f.funcID 392 n-- // offset n++ below 393 } 394 395 if printing { 396 // assume skip=0 for printing. 397 // 398 // Never elide wrappers if we haven't printed 399 // any frames. And don't elide wrappers that 400 // called panic rather than the wrapped 401 // function. Otherwise, leave them out. 402 403 // backup to CALL instruction to read inlining info (same logic as below) 404 tracepc := frame.pc 405 if (n > 0 || flags&_TraceTrap == 0) && frame.pc > f.entry && !waspanic { 406 tracepc-- 407 } 408 // If there is inlining info, print the inner frames. 409 if inldata := funcdata(f, _FUNCDATA_InlTree); inldata != nil { 410 inltree := (*[1 << 20]inlinedCall)(inldata) 411 for { 412 ix := pcdatavalue(f, _PCDATA_InlTreeIndex, tracepc, nil) 413 if ix < 0 { 414 break 415 } 416 if (flags&_TraceRuntimeFrames) != 0 || showframe(f, gp, nprint == 0, inltree[ix].funcID, lastFuncID) { 417 name := funcnameFromNameoff(f, inltree[ix].func_) 418 file, line := funcline(f, tracepc) 419 print(name, "(...)\n") 420 print("\t", file, ":", line, "\n") 421 nprint++ 422 } 423 lastFuncID = inltree[ix].funcID 424 // Back up to an instruction in the "caller". 425 tracepc = frame.fn.entry + uintptr(inltree[ix].parentPc) 426 } 427 } 428 if (flags&_TraceRuntimeFrames) != 0 || showframe(f, gp, nprint == 0, f.funcID, lastFuncID) { 429 // Print during crash. 430 // main(0x1, 0x2, 0x3) 431 // /home/rsc/go/src/runtime/x.go:23 +0xf 432 // 433 name := funcname(f) 434 file, line := funcline(f, tracepc) 435 if name == "runtime.gopanic" { 436 name = "panic" 437 } 438 print(name, "(") 439 argp := (*[100]uintptr)(unsafe.Pointer(frame.argp)) 440 for i := uintptr(0); i < frame.arglen/sys.PtrSize; i++ { 441 if i >= 10 { 442 print(", ...") 443 break 444 } 445 if i != 0 { 446 print(", ") 447 } 448 print(hex(argp[i])) 449 } 450 print(")\n") 451 print("\t", file, ":", line) 452 if frame.pc > f.entry { 453 print(" +", hex(frame.pc-f.entry)) 454 } 455 if gp.m != nil && gp.m.throwing > 0 && gp == gp.m.curg || level >= 2 { 456 print(" fp=", hex(frame.fp), " sp=", hex(frame.sp), " pc=", hex(frame.pc)) 457 } 458 print("\n") 459 nprint++ 460 } 461 lastFuncID = f.funcID 462 } 463 n++ 464 465 if f.funcID == funcID_cgocallback_gofunc && len(cgoCtxt) > 0 { 466 ctxt := cgoCtxt[len(cgoCtxt)-1] 467 cgoCtxt = cgoCtxt[:len(cgoCtxt)-1] 468 469 // skip only applies to Go frames. 470 // callback != nil only used when we only care 471 // about Go frames. 472 if skip == 0 && callback == nil { 473 n = tracebackCgoContext(pcbuf, printing, ctxt, n, max) 474 } 475 } 476 477 waspanic = f.funcID == funcID_sigpanic 478 injectedCall := waspanic || f.funcID == funcID_asyncPreempt 479 480 // Do not unwind past the bottom of the stack. 481 if !flr.valid() { 482 break 483 } 484 485 // Unwind to next frame. 486 frame.fn = flr 487 frame.pc = frame.lr 488 frame.lr = 0 489 frame.sp = frame.fp 490 frame.fp = 0 491 frame.argmap = nil 492 493 // On link register architectures, sighandler saves the LR on stack 494 // before faking a call. 495 if usesLR && injectedCall { 496 x := *(*uintptr)(unsafe.Pointer(frame.sp)) 497 frame.sp += sys.MinFrameSize 498 if GOARCH == "arm64" { 499 // arm64 needs 16-byte aligned SP, always 500 frame.sp += sys.PtrSize 501 } 502 f = findfunc(frame.pc) 503 frame.fn = f 504 if !f.valid() { 505 frame.pc = x 506 } else if funcspdelta(f, frame.pc, &cache) == 0 { 507 frame.lr = x 508 } 509 } 510 } 511 512 if printing { 513 n = nprint 514 } 515 516 // Note that panic != nil is okay here: there can be leftover panics, 517 // because the defers on the panic stack do not nest in frame order as 518 // they do on the defer stack. If you have: 519 // 520 // frame 1 defers d1 521 // frame 2 defers d2 522 // frame 3 defers d3 523 // frame 4 panics 524 // frame 4's panic starts running defers 525 // frame 5, running d3, defers d4 526 // frame 5 panics 527 // frame 5's panic starts running defers 528 // frame 6, running d4, garbage collects 529 // frame 6, running d2, garbage collects 530 // 531 // During the execution of d4, the panic stack is d4 -> d3, which 532 // is nested properly, and we'll treat frame 3 as resumable, because we 533 // can find d3. (And in fact frame 3 is resumable. If d4 recovers 534 // and frame 5 continues running, d3, d3 can recover and we'll 535 // resume execution in (returning from) frame 3.) 536 // 537 // During the execution of d2, however, the panic stack is d2 -> d3, 538 // which is inverted. The scan will match d2 to frame 2 but having 539 // d2 on the stack until then means it will not match d3 to frame 3. 540 // This is okay: if we're running d2, then all the defers after d2 have 541 // completed and their corresponding frames are dead. Not finding d3 542 // for frame 3 means we'll set frame 3's continpc == 0, which is correct 543 // (frame 3 is dead). At the end of the walk the panic stack can thus 544 // contain defers (d3 in this case) for dead frames. The inversion here 545 // always indicates a dead frame, and the effect of the inversion on the 546 // scan is to hide those dead frames, so the scan is still okay: 547 // what's left on the panic stack are exactly (and only) the dead frames. 548 // 549 // We require callback != nil here because only when callback != nil 550 // do we know that gentraceback is being called in a "must be correct" 551 // context as opposed to a "best effort" context. The tracebacks with 552 // callbacks only happen when everything is stopped nicely. 553 // At other times, such as when gathering a stack for a profiling signal 554 // or when printing a traceback during a crash, everything may not be 555 // stopped nicely, and the stack walk may not be able to complete. 556 if callback != nil && n < max && frame.sp != gp.stktopsp { 557 print("runtime: g", gp.goid, ": frame.sp=", hex(frame.sp), " top=", hex(gp.stktopsp), "\n") 558 print("\tstack=[", hex(gp.stack.lo), "-", hex(gp.stack.hi), "] n=", n, " max=", max, "\n") 559 throw("traceback did not unwind completely") 560 } 561 562 return n 563 } 564 565 // reflectMethodValue is a partial duplicate of reflect.makeFuncImpl 566 // and reflect.methodValue. 567 type reflectMethodValue struct { 568 fn uintptr 569 stack *bitvector // ptrmap for both args and results 570 argLen uintptr // just args 571 } 572 573 // getArgInfoFast returns the argument frame information for a call to f. 574 // It is short and inlineable. However, it does not handle all functions. 575 // If ok reports false, you must call getArgInfo instead. 576 // TODO(josharian): once we do mid-stack inlining, 577 // call getArgInfo directly from getArgInfoFast and stop returning an ok bool. 578 func getArgInfoFast(f funcInfo, needArgMap bool) (arglen uintptr, argmap *bitvector, ok bool) { 579 return uintptr(f.args), nil, !(needArgMap && f.args == _ArgsSizeUnknown) 580 } 581 582 // getArgInfo returns the argument frame information for a call to f 583 // with call frame frame. 584 // 585 // This is used for both actual calls with active stack frames and for 586 // deferred calls or goroutines that are not yet executing. If this is an actual 587 // call, ctxt must be nil (getArgInfo will retrieve what it needs from 588 // the active stack frame). If this is a deferred call or unstarted goroutine, 589 // ctxt must be the function object that was deferred or go'd. 590 func getArgInfo(frame *stkframe, f funcInfo, needArgMap bool, ctxt *funcval) (arglen uintptr, argmap *bitvector) { 591 arglen = uintptr(f.args) 592 if needArgMap && f.args == _ArgsSizeUnknown { 593 // Extract argument bitmaps for reflect stubs from the calls they made to reflect. 594 switch funcname(f) { 595 case "reflect.makeFuncStub", "reflect.methodValueCall": 596 // These take a *reflect.methodValue as their 597 // context register. 598 var mv *reflectMethodValue 599 var retValid bool 600 if ctxt != nil { 601 // This is not an actual call, but a 602 // deferred call or an unstarted goroutine. 603 // The function value is itself the *reflect.methodValue. 604 mv = (*reflectMethodValue)(unsafe.Pointer(ctxt)) 605 } else { 606 // This is a real call that took the 607 // *reflect.methodValue as its context 608 // register and immediately saved it 609 // to 0(SP). Get the methodValue from 610 // 0(SP). 611 arg0 := frame.sp + sys.MinFrameSize 612 mv = *(**reflectMethodValue)(unsafe.Pointer(arg0)) 613 // Figure out whether the return values are valid. 614 // Reflect will update this value after it copies 615 // in the return values. 616 retValid = *(*bool)(unsafe.Pointer(arg0 + 3*sys.PtrSize)) 617 } 618 if mv.fn != f.entry { 619 print("runtime: confused by ", funcname(f), "\n") 620 throw("reflect mismatch") 621 } 622 bv := mv.stack 623 arglen = uintptr(bv.n * sys.PtrSize) 624 if !retValid { 625 arglen = uintptr(mv.argLen) &^ (sys.PtrSize - 1) 626 } 627 argmap = bv 628 } 629 } 630 return 631 } 632 633 // tracebackCgoContext handles tracing back a cgo context value, from 634 // the context argument to setCgoTraceback, for the gentraceback 635 // function. It returns the new value of n. 636 func tracebackCgoContext(pcbuf *uintptr, printing bool, ctxt uintptr, n, max int) int { 637 var cgoPCs [32]uintptr 638 cgoContextPCs(ctxt, cgoPCs[:]) 639 var arg cgoSymbolizerArg 640 anySymbolized := false 641 for _, pc := range cgoPCs { 642 if pc == 0 || n >= max { 643 break 644 } 645 if pcbuf != nil { 646 (*[1 << 20]uintptr)(unsafe.Pointer(pcbuf))[n] = pc 647 } 648 if printing { 649 if cgoSymbolizer == nil { 650 print("non-Go function at pc=", hex(pc), "\n") 651 } else { 652 c := printOneCgoTraceback(pc, max-n, &arg) 653 n += c - 1 // +1 a few lines down 654 anySymbolized = true 655 } 656 } 657 n++ 658 } 659 if anySymbolized { 660 arg.pc = 0 661 callCgoSymbolizer(&arg) 662 } 663 return n 664 } 665 666 func printcreatedby(gp *g) { 667 // Show what created goroutine, except main goroutine (goid 1). 668 pc := gp.gopc 669 f := findfunc(pc) 670 if f.valid() && showframe(f, gp, false, funcID_normal, funcID_normal) && gp.goid != 1 { 671 printcreatedby1(f, pc) 672 } 673 } 674 675 func printcreatedby1(f funcInfo, pc uintptr) { 676 print("created by ", funcname(f), "\n") 677 tracepc := pc // back up to CALL instruction for funcline. 678 if pc > f.entry { 679 tracepc -= sys.PCQuantum 680 } 681 file, line := funcline(f, tracepc) 682 print("\t", file, ":", line) 683 if pc > f.entry { 684 print(" +", hex(pc-f.entry)) 685 } 686 print("\n") 687 } 688 689 func traceback(pc, sp, lr uintptr, gp *g) { 690 traceback1(pc, sp, lr, gp, 0) 691 } 692 693 // tracebacktrap is like traceback but expects that the PC and SP were obtained 694 // from a trap, not from gp->sched or gp->syscallpc/gp->syscallsp or getcallerpc/getcallersp. 695 // Because they are from a trap instead of from a saved pair, 696 // the initial PC must not be rewound to the previous instruction. 697 // (All the saved pairs record a PC that is a return address, so we 698 // rewind it into the CALL instruction.) 699 // If gp.m.libcall{g,pc,sp} information is available, it uses that information in preference to 700 // the pc/sp/lr passed in. 701 func tracebacktrap(pc, sp, lr uintptr, gp *g) { 702 if gp.m.libcallsp != 0 { 703 // We're in C code somewhere, traceback from the saved position. 704 traceback1(gp.m.libcallpc, gp.m.libcallsp, 0, gp.m.libcallg.ptr(), 0) 705 return 706 } 707 traceback1(pc, sp, lr, gp, _TraceTrap) 708 } 709 710 func traceback1(pc, sp, lr uintptr, gp *g, flags uint) { 711 // If the goroutine is in cgo, and we have a cgo traceback, print that. 712 if iscgo && gp.m != nil && gp.m.ncgo > 0 && gp.syscallsp != 0 && gp.m.cgoCallers != nil && gp.m.cgoCallers[0] != 0 { 713 // Lock cgoCallers so that a signal handler won't 714 // change it, copy the array, reset it, unlock it. 715 // We are locked to the thread and are not running 716 // concurrently with a signal handler. 717 // We just have to stop a signal handler from interrupting 718 // in the middle of our copy. 719 atomic.Store(&gp.m.cgoCallersUse, 1) 720 cgoCallers := *gp.m.cgoCallers 721 gp.m.cgoCallers[0] = 0 722 atomic.Store(&gp.m.cgoCallersUse, 0) 723 724 printCgoTraceback(&cgoCallers) 725 } 726 727 var n int 728 if readgstatus(gp)&^_Gscan == _Gsyscall { 729 // Override registers if blocked in system call. 730 pc = gp.syscallpc 731 sp = gp.syscallsp 732 flags &^= _TraceTrap 733 } 734 // Print traceback. By default, omits runtime frames. 735 // If that means we print nothing at all, repeat forcing all frames printed. 736 n = gentraceback(pc, sp, lr, gp, 0, nil, _TracebackMaxFrames, nil, nil, flags) 737 if n == 0 && (flags&_TraceRuntimeFrames) == 0 { 738 n = gentraceback(pc, sp, lr, gp, 0, nil, _TracebackMaxFrames, nil, nil, flags|_TraceRuntimeFrames) 739 } 740 if n == _TracebackMaxFrames { 741 print("...additional frames elided...\n") 742 } 743 printcreatedby(gp) 744 745 if gp.ancestors == nil { 746 return 747 } 748 for _, ancestor := range *gp.ancestors { 749 printAncestorTraceback(ancestor) 750 } 751 } 752 753 // printAncestorTraceback prints the traceback of the given ancestor. 754 // TODO: Unify this with gentraceback and CallersFrames. 755 func printAncestorTraceback(ancestor ancestorInfo) { 756 print("[originating from goroutine ", ancestor.goid, "]:\n") 757 for fidx, pc := range ancestor.pcs { 758 f := findfunc(pc) // f previously validated 759 if showfuncinfo(f, fidx == 0, funcID_normal, funcID_normal) { 760 printAncestorTracebackFuncInfo(f, pc) 761 } 762 } 763 if len(ancestor.pcs) == _TracebackMaxFrames { 764 print("...additional frames elided...\n") 765 } 766 // Show what created goroutine, except main goroutine (goid 1). 767 f := findfunc(ancestor.gopc) 768 if f.valid() && showfuncinfo(f, false, funcID_normal, funcID_normal) && ancestor.goid != 1 { 769 printcreatedby1(f, ancestor.gopc) 770 } 771 } 772 773 // printAncestorTraceback prints the given function info at a given pc 774 // within an ancestor traceback. The precision of this info is reduced 775 // due to only have access to the pcs at the time of the caller 776 // goroutine being created. 777 func printAncestorTracebackFuncInfo(f funcInfo, pc uintptr) { 778 name := funcname(f) 779 if inldata := funcdata(f, _FUNCDATA_InlTree); inldata != nil { 780 inltree := (*[1 << 20]inlinedCall)(inldata) 781 ix := pcdatavalue(f, _PCDATA_InlTreeIndex, pc, nil) 782 if ix >= 0 { 783 name = funcnameFromNameoff(f, inltree[ix].func_) 784 } 785 } 786 file, line := funcline(f, pc) 787 if name == "runtime.gopanic" { 788 name = "panic" 789 } 790 print(name, "(...)\n") 791 print("\t", file, ":", line) 792 if pc > f.entry { 793 print(" +", hex(pc-f.entry)) 794 } 795 print("\n") 796 } 797 798 func callers(skip int, pcbuf []uintptr) int { 799 sp := getcallersp() 800 pc := getcallerpc() 801 gp := getg() 802 var n int 803 systemstack(func() { 804 n = gentraceback(pc, sp, 0, gp, skip, &pcbuf[0], len(pcbuf), nil, nil, 0) 805 }) 806 return n 807 } 808 809 func gcallers(gp *g, skip int, pcbuf []uintptr) int { 810 return gentraceback(^uintptr(0), ^uintptr(0), 0, gp, skip, &pcbuf[0], len(pcbuf), nil, nil, 0) 811 } 812 813 // showframe reports whether the frame with the given characteristics should 814 // be printed during a traceback. 815 func showframe(f funcInfo, gp *g, firstFrame bool, funcID, childID funcID) bool { 816 g := getg() 817 if g.m.throwing > 0 && gp != nil && (gp == g.m.curg || gp == g.m.caughtsig.ptr()) { 818 return true 819 } 820 return showfuncinfo(f, firstFrame, funcID, childID) 821 } 822 823 // showfuncinfo reports whether a function with the given characteristics should 824 // be printed during a traceback. 825 func showfuncinfo(f funcInfo, firstFrame bool, funcID, childID funcID) bool { 826 level, _, _ := gotraceback() 827 if level > 1 { 828 // Show all frames. 829 return true 830 } 831 832 if !f.valid() { 833 return false 834 } 835 836 if funcID == funcID_wrapper && elideWrapperCalling(childID) { 837 return false 838 } 839 840 name := funcname(f) 841 842 // Special case: always show runtime.gopanic frame 843 // in the middle of a stack trace, so that we can 844 // see the boundary between ordinary code and 845 // panic-induced deferred code. 846 // See golang.org/issue/5832. 847 if name == "runtime.gopanic" && !firstFrame { 848 return true 849 } 850 851 return contains(name, ".") && (!hasPrefix(name, "runtime.") || isExportedRuntime(name)) 852 } 853 854 // isExportedRuntime reports whether name is an exported runtime function. 855 // It is only for runtime functions, so ASCII A-Z is fine. 856 func isExportedRuntime(name string) bool { 857 const n = len("runtime.") 858 return len(name) > n && name[:n] == "runtime." && 'A' <= name[n] && name[n] <= 'Z' 859 } 860 861 // elideWrapperCalling reports whether a wrapper function that called 862 // function id should be elided from stack traces. 863 func elideWrapperCalling(id funcID) bool { 864 // If the wrapper called a panic function instead of the 865 // wrapped function, we want to include it in stacks. 866 return !(id == funcID_gopanic || id == funcID_sigpanic || id == funcID_panicwrap) 867 } 868 869 var gStatusStrings = [...]string{ 870 _Gidle: "idle", 871 _Grunnable: "runnable", 872 _Grunning: "running", 873 _Gsyscall: "syscall", 874 _Gwaiting: "waiting", 875 _Gdead: "dead", 876 _Gcopystack: "copystack", 877 _Gpreempted: "preempted", 878 } 879 880 func goroutineheader(gp *g) { 881 gpstatus := readgstatus(gp) 882 883 isScan := gpstatus&_Gscan != 0 884 gpstatus &^= _Gscan // drop the scan bit 885 886 // Basic string status 887 var status string 888 if 0 <= gpstatus && gpstatus < uint32(len(gStatusStrings)) { 889 status = gStatusStrings[gpstatus] 890 } else { 891 status = "???" 892 } 893 894 // Override. 895 if gpstatus == _Gwaiting && gp.waitreason != waitReasonZero { 896 status = gp.waitreason.String() 897 } 898 899 // approx time the G is blocked, in minutes 900 var waitfor int64 901 if (gpstatus == _Gwaiting || gpstatus == _Gsyscall) && gp.waitsince != 0 { 902 waitfor = (nanotime() - gp.waitsince) / 60e9 903 } 904 print("goroutine ", gp.goid, " [", status) 905 if isScan { 906 print(" (scan)") 907 } 908 if waitfor >= 1 { 909 print(", ", waitfor, " minutes") 910 } 911 if gp.lockedm != 0 { 912 print(", locked to thread") 913 } 914 print("]:\n") 915 } 916 917 func tracebackothers(me *g) { 918 level, _, _ := gotraceback() 919 920 // Show the current goroutine first, if we haven't already. 921 g := getg() 922 gp := g.m.curg 923 if gp != nil && gp != me { 924 print("\n") 925 goroutineheader(gp) 926 traceback(^uintptr(0), ^uintptr(0), 0, gp) 927 } 928 929 lock(&allglock) 930 for _, gp := range allgs { 931 if gp == me || gp == g.m.curg || readgstatus(gp) == _Gdead || isSystemGoroutine(gp, false) && level < 2 { 932 continue 933 } 934 print("\n") 935 goroutineheader(gp) 936 // Note: gp.m == g.m occurs when tracebackothers is 937 // called from a signal handler initiated during a 938 // systemstack call. The original G is still in the 939 // running state, and we want to print its stack. 940 if gp.m != g.m && readgstatus(gp)&^_Gscan == _Grunning { 941 print("\tgoroutine running on other thread; stack unavailable\n") 942 printcreatedby(gp) 943 } else { 944 traceback(^uintptr(0), ^uintptr(0), 0, gp) 945 } 946 } 947 unlock(&allglock) 948 } 949 950 // tracebackHexdump hexdumps part of stk around frame.sp and frame.fp 951 // for debugging purposes. If the address bad is included in the 952 // hexdumped range, it will mark it as well. 953 func tracebackHexdump(stk stack, frame *stkframe, bad uintptr) { 954 const expand = 32 * sys.PtrSize 955 const maxExpand = 256 * sys.PtrSize 956 // Start around frame.sp. 957 lo, hi := frame.sp, frame.sp 958 // Expand to include frame.fp. 959 if frame.fp != 0 && frame.fp < lo { 960 lo = frame.fp 961 } 962 if frame.fp != 0 && frame.fp > hi { 963 hi = frame.fp 964 } 965 // Expand a bit more. 966 lo, hi = lo-expand, hi+expand 967 // But don't go too far from frame.sp. 968 if lo < frame.sp-maxExpand { 969 lo = frame.sp - maxExpand 970 } 971 if hi > frame.sp+maxExpand { 972 hi = frame.sp + maxExpand 973 } 974 // And don't go outside the stack bounds. 975 if lo < stk.lo { 976 lo = stk.lo 977 } 978 if hi > stk.hi { 979 hi = stk.hi 980 } 981 982 // Print the hex dump. 983 print("stack: frame={sp:", hex(frame.sp), ", fp:", hex(frame.fp), "} stack=[", hex(stk.lo), ",", hex(stk.hi), ")\n") 984 hexdumpWords(lo, hi, func(p uintptr) byte { 985 switch p { 986 case frame.fp: 987 return '>' 988 case frame.sp: 989 return '<' 990 case bad: 991 return '!' 992 } 993 return 0 994 }) 995 } 996 997 // Does f mark the top of a goroutine stack? 998 func topofstack(f funcInfo, g0 bool) bool { 999 return f.funcID == funcID_goexit || 1000 f.funcID == funcID_mstart || 1001 f.funcID == funcID_mcall || 1002 f.funcID == funcID_morestack || 1003 f.funcID == funcID_rt0_go || 1004 f.funcID == funcID_externalthreadhandler || 1005 // asmcgocall is TOS on the system stack because it 1006 // switches to the system stack, but in this case we 1007 // can come back to the regular stack and still want 1008 // to be able to unwind through the call that appeared 1009 // on the regular stack. 1010 (g0 && f.funcID == funcID_asmcgocall) 1011 } 1012 1013 // isSystemGoroutine reports whether the goroutine g must be omitted 1014 // in stack dumps and deadlock detector. This is any goroutine that 1015 // starts at a runtime.* entry point, except for runtime.main, 1016 // runtime.handleAsyncEvent (wasm only) and sometimes runtime.runfinq. 1017 // 1018 // If fixed is true, any goroutine that can vary between user and 1019 // system (that is, the finalizer goroutine) is considered a user 1020 // goroutine. 1021 func isSystemGoroutine(gp *g, fixed bool) bool { 1022 // Keep this in sync with cmd/trace/trace.go:isSystemGoroutine. 1023 f := findfunc(gp.startpc) 1024 if !f.valid() { 1025 return false 1026 } 1027 if f.funcID == funcID_runtime_main || f.funcID == funcID_handleAsyncEvent { 1028 return false 1029 } 1030 if f.funcID == funcID_runfinq { 1031 // We include the finalizer goroutine if it's calling 1032 // back into user code. 1033 if fixed { 1034 // This goroutine can vary. In fixed mode, 1035 // always consider it a user goroutine. 1036 return false 1037 } 1038 return !fingRunning 1039 } 1040 return hasPrefix(funcname(f), "runtime.") 1041 } 1042 1043 // SetCgoTraceback records three C functions to use to gather 1044 // traceback information from C code and to convert that traceback 1045 // information into symbolic information. These are used when printing 1046 // stack traces for a program that uses cgo. 1047 // 1048 // The traceback and context functions may be called from a signal 1049 // handler, and must therefore use only async-signal safe functions. 1050 // The symbolizer function may be called while the program is 1051 // crashing, and so must be cautious about using memory. None of the 1052 // functions may call back into Go. 1053 // 1054 // The context function will be called with a single argument, a 1055 // pointer to a struct: 1056 // 1057 // struct { 1058 // Context uintptr 1059 // } 1060 // 1061 // In C syntax, this struct will be 1062 // 1063 // struct { 1064 // uintptr_t Context; 1065 // }; 1066 // 1067 // If the Context field is 0, the context function is being called to 1068 // record the current traceback context. It should record in the 1069 // Context field whatever information is needed about the current 1070 // point of execution to later produce a stack trace, probably the 1071 // stack pointer and PC. In this case the context function will be 1072 // called from C code. 1073 // 1074 // If the Context field is not 0, then it is a value returned by a 1075 // previous call to the context function. This case is called when the 1076 // context is no longer needed; that is, when the Go code is returning 1077 // to its C code caller. This permits the context function to release 1078 // any associated resources. 1079 // 1080 // While it would be correct for the context function to record a 1081 // complete a stack trace whenever it is called, and simply copy that 1082 // out in the traceback function, in a typical program the context 1083 // function will be called many times without ever recording a 1084 // traceback for that context. Recording a complete stack trace in a 1085 // call to the context function is likely to be inefficient. 1086 // 1087 // The traceback function will be called with a single argument, a 1088 // pointer to a struct: 1089 // 1090 // struct { 1091 // Context uintptr 1092 // SigContext uintptr 1093 // Buf *uintptr 1094 // Max uintptr 1095 // } 1096 // 1097 // In C syntax, this struct will be 1098 // 1099 // struct { 1100 // uintptr_t Context; 1101 // uintptr_t SigContext; 1102 // uintptr_t* Buf; 1103 // uintptr_t Max; 1104 // }; 1105 // 1106 // The Context field will be zero to gather a traceback from the 1107 // current program execution point. In this case, the traceback 1108 // function will be called from C code. 1109 // 1110 // Otherwise Context will be a value previously returned by a call to 1111 // the context function. The traceback function should gather a stack 1112 // trace from that saved point in the program execution. The traceback 1113 // function may be called from an execution thread other than the one 1114 // that recorded the context, but only when the context is known to be 1115 // valid and unchanging. The traceback function may also be called 1116 // deeper in the call stack on the same thread that recorded the 1117 // context. The traceback function may be called multiple times with 1118 // the same Context value; it will usually be appropriate to cache the 1119 // result, if possible, the first time this is called for a specific 1120 // context value. 1121 // 1122 // If the traceback function is called from a signal handler on a Unix 1123 // system, SigContext will be the signal context argument passed to 1124 // the signal handler (a C ucontext_t* cast to uintptr_t). This may be 1125 // used to start tracing at the point where the signal occurred. If 1126 // the traceback function is not called from a signal handler, 1127 // SigContext will be zero. 1128 // 1129 // Buf is where the traceback information should be stored. It should 1130 // be PC values, such that Buf[0] is the PC of the caller, Buf[1] is 1131 // the PC of that function's caller, and so on. Max is the maximum 1132 // number of entries to store. The function should store a zero to 1133 // indicate the top of the stack, or that the caller is on a different 1134 // stack, presumably a Go stack. 1135 // 1136 // Unlike runtime.Callers, the PC values returned should, when passed 1137 // to the symbolizer function, return the file/line of the call 1138 // instruction. No additional subtraction is required or appropriate. 1139 // 1140 // On all platforms, the traceback function is invoked when a call from 1141 // Go to C to Go requests a stack trace. On linux/amd64, linux/ppc64le, 1142 // and freebsd/amd64, the traceback function is also invoked when a 1143 // signal is received by a thread that is executing a cgo call. The 1144 // traceback function should not make assumptions about when it is 1145 // called, as future versions of Go may make additional calls. 1146 // 1147 // The symbolizer function will be called with a single argument, a 1148 // pointer to a struct: 1149 // 1150 // struct { 1151 // PC uintptr // program counter to fetch information for 1152 // File *byte // file name (NUL terminated) 1153 // Lineno uintptr // line number 1154 // Func *byte // function name (NUL terminated) 1155 // Entry uintptr // function entry point 1156 // More uintptr // set non-zero if more info for this PC 1157 // Data uintptr // unused by runtime, available for function 1158 // } 1159 // 1160 // In C syntax, this struct will be 1161 // 1162 // struct { 1163 // uintptr_t PC; 1164 // char* File; 1165 // uintptr_t Lineno; 1166 // char* Func; 1167 // uintptr_t Entry; 1168 // uintptr_t More; 1169 // uintptr_t Data; 1170 // }; 1171 // 1172 // The PC field will be a value returned by a call to the traceback 1173 // function. 1174 // 1175 // The first time the function is called for a particular traceback, 1176 // all the fields except PC will be 0. The function should fill in the 1177 // other fields if possible, setting them to 0/nil if the information 1178 // is not available. The Data field may be used to store any useful 1179 // information across calls. The More field should be set to non-zero 1180 // if there is more information for this PC, zero otherwise. If More 1181 // is set non-zero, the function will be called again with the same 1182 // PC, and may return different information (this is intended for use 1183 // with inlined functions). If More is zero, the function will be 1184 // called with the next PC value in the traceback. When the traceback 1185 // is complete, the function will be called once more with PC set to 1186 // zero; this may be used to free any information. Each call will 1187 // leave the fields of the struct set to the same values they had upon 1188 // return, except for the PC field when the More field is zero. The 1189 // function must not keep a copy of the struct pointer between calls. 1190 // 1191 // When calling SetCgoTraceback, the version argument is the version 1192 // number of the structs that the functions expect to receive. 1193 // Currently this must be zero. 1194 // 1195 // The symbolizer function may be nil, in which case the results of 1196 // the traceback function will be displayed as numbers. If the 1197 // traceback function is nil, the symbolizer function will never be 1198 // called. The context function may be nil, in which case the 1199 // traceback function will only be called with the context field set 1200 // to zero. If the context function is nil, then calls from Go to C 1201 // to Go will not show a traceback for the C portion of the call stack. 1202 // 1203 // SetCgoTraceback should be called only once, ideally from an init function. 1204 func SetCgoTraceback(version int, traceback, context, symbolizer unsafe.Pointer) { 1205 if version != 0 { 1206 panic("unsupported version") 1207 } 1208 1209 if cgoTraceback != nil && cgoTraceback != traceback || 1210 cgoContext != nil && cgoContext != context || 1211 cgoSymbolizer != nil && cgoSymbolizer != symbolizer { 1212 panic("call SetCgoTraceback only once") 1213 } 1214 1215 cgoTraceback = traceback 1216 cgoContext = context 1217 cgoSymbolizer = symbolizer 1218 1219 // The context function is called when a C function calls a Go 1220 // function. As such it is only called by C code in runtime/cgo. 1221 if _cgo_set_context_function != nil { 1222 cgocall(_cgo_set_context_function, context) 1223 } 1224 } 1225 1226 var cgoTraceback unsafe.Pointer 1227 var cgoContext unsafe.Pointer 1228 var cgoSymbolizer unsafe.Pointer 1229 1230 // cgoTracebackArg is the type passed to cgoTraceback. 1231 type cgoTracebackArg struct { 1232 context uintptr 1233 sigContext uintptr 1234 buf *uintptr 1235 max uintptr 1236 } 1237 1238 // cgoContextArg is the type passed to the context function. 1239 type cgoContextArg struct { 1240 context uintptr 1241 } 1242 1243 // cgoSymbolizerArg is the type passed to cgoSymbolizer. 1244 type cgoSymbolizerArg struct { 1245 pc uintptr 1246 file *byte 1247 lineno uintptr 1248 funcName *byte 1249 entry uintptr 1250 more uintptr 1251 data uintptr 1252 } 1253 1254 // cgoTraceback prints a traceback of callers. 1255 func printCgoTraceback(callers *cgoCallers) { 1256 if cgoSymbolizer == nil { 1257 for _, c := range callers { 1258 if c == 0 { 1259 break 1260 } 1261 print("non-Go function at pc=", hex(c), "\n") 1262 } 1263 return 1264 } 1265 1266 var arg cgoSymbolizerArg 1267 for _, c := range callers { 1268 if c == 0 { 1269 break 1270 } 1271 printOneCgoTraceback(c, 0x7fffffff, &arg) 1272 } 1273 arg.pc = 0 1274 callCgoSymbolizer(&arg) 1275 } 1276 1277 // printOneCgoTraceback prints the traceback of a single cgo caller. 1278 // This can print more than one line because of inlining. 1279 // Returns the number of frames printed. 1280 func printOneCgoTraceback(pc uintptr, max int, arg *cgoSymbolizerArg) int { 1281 c := 0 1282 arg.pc = pc 1283 for c <= max { 1284 callCgoSymbolizer(arg) 1285 if arg.funcName != nil { 1286 // Note that we don't print any argument 1287 // information here, not even parentheses. 1288 // The symbolizer must add that if appropriate. 1289 println(gostringnocopy(arg.funcName)) 1290 } else { 1291 println("non-Go function") 1292 } 1293 print("\t") 1294 if arg.file != nil { 1295 print(gostringnocopy(arg.file), ":", arg.lineno, " ") 1296 } 1297 print("pc=", hex(pc), "\n") 1298 c++ 1299 if arg.more == 0 { 1300 break 1301 } 1302 } 1303 return c 1304 } 1305 1306 // callCgoSymbolizer calls the cgoSymbolizer function. 1307 func callCgoSymbolizer(arg *cgoSymbolizerArg) { 1308 call := cgocall 1309 if panicking > 0 || getg().m.curg != getg() { 1310 // We do not want to call into the scheduler when panicking 1311 // or when on the system stack. 1312 call = asmcgocall 1313 } 1314 if msanenabled { 1315 msanwrite(unsafe.Pointer(arg), unsafe.Sizeof(cgoSymbolizerArg{})) 1316 } 1317 call(cgoSymbolizer, noescape(unsafe.Pointer(arg))) 1318 } 1319 1320 // cgoContextPCs gets the PC values from a cgo traceback. 1321 func cgoContextPCs(ctxt uintptr, buf []uintptr) { 1322 if cgoTraceback == nil { 1323 return 1324 } 1325 call := cgocall 1326 if panicking > 0 || getg().m.curg != getg() { 1327 // We do not want to call into the scheduler when panicking 1328 // or when on the system stack. 1329 call = asmcgocall 1330 } 1331 arg := cgoTracebackArg{ 1332 context: ctxt, 1333 buf: (*uintptr)(noescape(unsafe.Pointer(&buf[0]))), 1334 max: uintptr(len(buf)), 1335 } 1336 if msanenabled { 1337 msanwrite(unsafe.Pointer(&arg), unsafe.Sizeof(arg)) 1338 } 1339 call(cgoTraceback, noescape(unsafe.Pointer(&arg))) 1340 } 1341