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 has ptrSize == 4 but the CALL instruction still 30 // stores an 8-byte return PC onto the stack. To accommodate this, we use 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 if (n > 0 || flags&_TraceTrap == 0) && frame.pc > f.entry && !waspanic { 344 tracepc-- 345 } 346 347 // If there is inlining info, record the inner frames. 348 if inldata := funcdata(f, _FUNCDATA_InlTree); inldata != nil { 349 inltree := (*[1 << 20]inlinedCall)(inldata) 350 for { 351 ix := pcdatavalue(f, _PCDATA_InlTreeIndex, tracepc, &cache) 352 if ix < 0 { 353 break 354 } 355 if inltree[ix].funcID == funcID_wrapper && elideWrapperCalling(lastFuncID) { 356 // ignore wrappers 357 } else if skip > 0 { 358 skip-- 359 } else if n < max { 360 (*[1 << 20]uintptr)(unsafe.Pointer(pcbuf))[n] = pc 361 n++ 362 } 363 lastFuncID = inltree[ix].funcID 364 // Back up to an instruction in the "caller". 365 tracepc = frame.fn.entry + uintptr(inltree[ix].parentPc) 366 pc = tracepc + 1 367 } 368 } 369 // Record the main frame. 370 if f.funcID == funcID_wrapper && elideWrapperCalling(lastFuncID) { 371 // Ignore wrapper functions (except when they trigger panics). 372 } else if skip > 0 { 373 skip-- 374 } else if n < max { 375 (*[1 << 20]uintptr)(unsafe.Pointer(pcbuf))[n] = pc 376 n++ 377 } 378 lastFuncID = f.funcID 379 n-- // offset n++ below 380 } 381 382 if printing { 383 // assume skip=0 for printing. 384 // 385 // Never elide wrappers if we haven't printed 386 // any frames. And don't elide wrappers that 387 // called panic rather than the wrapped 388 // function. Otherwise, leave them out. 389 390 // backup to CALL instruction to read inlining info (same logic as below) 391 tracepc := frame.pc 392 if (n > 0 || flags&_TraceTrap == 0) && frame.pc > f.entry && !waspanic { 393 tracepc-- 394 } 395 // If there is inlining info, print the inner frames. 396 if inldata := funcdata(f, _FUNCDATA_InlTree); inldata != nil { 397 inltree := (*[1 << 20]inlinedCall)(inldata) 398 for { 399 ix := pcdatavalue(f, _PCDATA_InlTreeIndex, tracepc, nil) 400 if ix < 0 { 401 break 402 } 403 if (flags&_TraceRuntimeFrames) != 0 || showframe(f, gp, nprint == 0, inltree[ix].funcID, lastFuncID) { 404 name := funcnameFromNameoff(f, inltree[ix].func_) 405 file, line := funcline(f, tracepc) 406 print(name, "(...)\n") 407 print("\t", file, ":", line, "\n") 408 nprint++ 409 } 410 lastFuncID = inltree[ix].funcID 411 // Back up to an instruction in the "caller". 412 tracepc = frame.fn.entry + uintptr(inltree[ix].parentPc) 413 } 414 } 415 if (flags&_TraceRuntimeFrames) != 0 || showframe(f, gp, nprint == 0, f.funcID, lastFuncID) { 416 // Print during crash. 417 // main(0x1, 0x2, 0x3) 418 // /home/rsc/go/src/runtime/x.go:23 +0xf 419 // 420 name := funcname(f) 421 file, line := funcline(f, tracepc) 422 if name == "runtime.gopanic" { 423 name = "panic" 424 } 425 print(name, "(") 426 argp := (*[100]uintptr)(unsafe.Pointer(frame.argp)) 427 for i := uintptr(0); i < frame.arglen/sys.PtrSize; i++ { 428 if i >= 10 { 429 print(", ...") 430 break 431 } 432 if i != 0 { 433 print(", ") 434 } 435 print(hex(argp[i])) 436 } 437 print(")\n") 438 print("\t", file, ":", line) 439 if frame.pc > f.entry { 440 print(" +", hex(frame.pc-f.entry)) 441 } 442 if gp.m != nil && gp.m.throwing > 0 && gp == gp.m.curg || level >= 2 { 443 print(" fp=", hex(frame.fp), " sp=", hex(frame.sp), " pc=", hex(frame.pc)) 444 } 445 print("\n") 446 nprint++ 447 } 448 lastFuncID = f.funcID 449 } 450 n++ 451 452 if f.funcID == funcID_cgocallback_gofunc && len(cgoCtxt) > 0 { 453 ctxt := cgoCtxt[len(cgoCtxt)-1] 454 cgoCtxt = cgoCtxt[:len(cgoCtxt)-1] 455 456 // skip only applies to Go frames. 457 // callback != nil only used when we only care 458 // about Go frames. 459 if skip == 0 && callback == nil { 460 n = tracebackCgoContext(pcbuf, printing, ctxt, n, max) 461 } 462 } 463 464 waspanic = f.funcID == funcID_sigpanic 465 466 // Do not unwind past the bottom of the stack. 467 if !flr.valid() { 468 break 469 } 470 471 // Unwind to next frame. 472 frame.fn = flr 473 frame.pc = frame.lr 474 frame.lr = 0 475 frame.sp = frame.fp 476 frame.fp = 0 477 frame.argmap = nil 478 479 // On link register architectures, sighandler saves the LR on stack 480 // before faking a call to sigpanic. 481 if usesLR && waspanic { 482 x := *(*uintptr)(unsafe.Pointer(frame.sp)) 483 frame.sp += sys.MinFrameSize 484 if GOARCH == "arm64" { 485 // arm64 needs 16-byte aligned SP, always 486 frame.sp += sys.PtrSize 487 } 488 f = findfunc(frame.pc) 489 frame.fn = f 490 if !f.valid() { 491 frame.pc = x 492 } else if funcspdelta(f, frame.pc, &cache) == 0 { 493 frame.lr = x 494 } 495 } 496 } 497 498 if printing { 499 n = nprint 500 } 501 502 // Note that panic != nil is okay here: there can be leftover panics, 503 // because the defers on the panic stack do not nest in frame order as 504 // they do on the defer stack. If you have: 505 // 506 // frame 1 defers d1 507 // frame 2 defers d2 508 // frame 3 defers d3 509 // frame 4 panics 510 // frame 4's panic starts running defers 511 // frame 5, running d3, defers d4 512 // frame 5 panics 513 // frame 5's panic starts running defers 514 // frame 6, running d4, garbage collects 515 // frame 6, running d2, garbage collects 516 // 517 // During the execution of d4, the panic stack is d4 -> d3, which 518 // is nested properly, and we'll treat frame 3 as resumable, because we 519 // can find d3. (And in fact frame 3 is resumable. If d4 recovers 520 // and frame 5 continues running, d3, d3 can recover and we'll 521 // resume execution in (returning from) frame 3.) 522 // 523 // During the execution of d2, however, the panic stack is d2 -> d3, 524 // which is inverted. The scan will match d2 to frame 2 but having 525 // d2 on the stack until then means it will not match d3 to frame 3. 526 // This is okay: if we're running d2, then all the defers after d2 have 527 // completed and their corresponding frames are dead. Not finding d3 528 // for frame 3 means we'll set frame 3's continpc == 0, which is correct 529 // (frame 3 is dead). At the end of the walk the panic stack can thus 530 // contain defers (d3 in this case) for dead frames. The inversion here 531 // always indicates a dead frame, and the effect of the inversion on the 532 // scan is to hide those dead frames, so the scan is still okay: 533 // what's left on the panic stack are exactly (and only) the dead frames. 534 // 535 // We require callback != nil here because only when callback != nil 536 // do we know that gentraceback is being called in a "must be correct" 537 // context as opposed to a "best effort" context. The tracebacks with 538 // callbacks only happen when everything is stopped nicely. 539 // At other times, such as when gathering a stack for a profiling signal 540 // or when printing a traceback during a crash, everything may not be 541 // stopped nicely, and the stack walk may not be able to complete. 542 if callback != nil && n < max && frame.sp != gp.stktopsp { 543 print("runtime: g", gp.goid, ": frame.sp=", hex(frame.sp), " top=", hex(gp.stktopsp), "\n") 544 print("\tstack=[", hex(gp.stack.lo), "-", hex(gp.stack.hi), "] n=", n, " max=", max, "\n") 545 throw("traceback did not unwind completely") 546 } 547 548 return n 549 } 550 551 // reflectMethodValue is a partial duplicate of reflect.makeFuncImpl 552 // and reflect.methodValue. 553 type reflectMethodValue struct { 554 fn uintptr 555 stack *bitvector // ptrmap for both args and results 556 argLen uintptr // just args 557 } 558 559 // getArgInfoFast returns the argument frame information for a call to f. 560 // It is short and inlineable. However, it does not handle all functions. 561 // If ok reports false, you must call getArgInfo instead. 562 // TODO(josharian): once we do mid-stack inlining, 563 // call getArgInfo directly from getArgInfoFast and stop returning an ok bool. 564 func getArgInfoFast(f funcInfo, needArgMap bool) (arglen uintptr, argmap *bitvector, ok bool) { 565 return uintptr(f.args), nil, !(needArgMap && f.args == _ArgsSizeUnknown) 566 } 567 568 // getArgInfo returns the argument frame information for a call to f 569 // with call frame frame. 570 // 571 // This is used for both actual calls with active stack frames and for 572 // deferred calls or goroutines that are not yet executing. If this is an actual 573 // call, ctxt must be nil (getArgInfo will retrieve what it needs from 574 // the active stack frame). If this is a deferred call or unstarted goroutine, 575 // ctxt must be the function object that was deferred or go'd. 576 func getArgInfo(frame *stkframe, f funcInfo, needArgMap bool, ctxt *funcval) (arglen uintptr, argmap *bitvector) { 577 arglen = uintptr(f.args) 578 if needArgMap && f.args == _ArgsSizeUnknown { 579 // Extract argument bitmaps for reflect stubs from the calls they made to reflect. 580 switch funcname(f) { 581 case "reflect.makeFuncStub", "reflect.methodValueCall": 582 // These take a *reflect.methodValue as their 583 // context register. 584 var mv *reflectMethodValue 585 var retValid bool 586 if ctxt != nil { 587 // This is not an actual call, but a 588 // deferred call or an unstarted goroutine. 589 // The function value is itself the *reflect.methodValue. 590 mv = (*reflectMethodValue)(unsafe.Pointer(ctxt)) 591 } else { 592 // This is a real call that took the 593 // *reflect.methodValue as its context 594 // register and immediately saved it 595 // to 0(SP). Get the methodValue from 596 // 0(SP). 597 arg0 := frame.sp + sys.MinFrameSize 598 mv = *(**reflectMethodValue)(unsafe.Pointer(arg0)) 599 // Figure out whether the return values are valid. 600 // Reflect will update this value after it copies 601 // in the return values. 602 retValid = *(*bool)(unsafe.Pointer(arg0 + 3*sys.PtrSize)) 603 } 604 if mv.fn != f.entry { 605 print("runtime: confused by ", funcname(f), "\n") 606 throw("reflect mismatch") 607 } 608 bv := mv.stack 609 arglen = uintptr(bv.n * sys.PtrSize) 610 if !retValid { 611 arglen = uintptr(mv.argLen) &^ (sys.PtrSize - 1) 612 } 613 argmap = bv 614 } 615 } 616 return 617 } 618 619 // tracebackCgoContext handles tracing back a cgo context value, from 620 // the context argument to setCgoTraceback, for the gentraceback 621 // function. It returns the new value of n. 622 func tracebackCgoContext(pcbuf *uintptr, printing bool, ctxt uintptr, n, max int) int { 623 var cgoPCs [32]uintptr 624 cgoContextPCs(ctxt, cgoPCs[:]) 625 var arg cgoSymbolizerArg 626 anySymbolized := false 627 for _, pc := range cgoPCs { 628 if pc == 0 || n >= max { 629 break 630 } 631 if pcbuf != nil { 632 (*[1 << 20]uintptr)(unsafe.Pointer(pcbuf))[n] = pc 633 } 634 if printing { 635 if cgoSymbolizer == nil { 636 print("non-Go function at pc=", hex(pc), "\n") 637 } else { 638 c := printOneCgoTraceback(pc, max-n, &arg) 639 n += c - 1 // +1 a few lines down 640 anySymbolized = true 641 } 642 } 643 n++ 644 } 645 if anySymbolized { 646 arg.pc = 0 647 callCgoSymbolizer(&arg) 648 } 649 return n 650 } 651 652 func printcreatedby(gp *g) { 653 // Show what created goroutine, except main goroutine (goid 1). 654 pc := gp.gopc 655 f := findfunc(pc) 656 if f.valid() && showframe(f, gp, false, funcID_normal, funcID_normal) && gp.goid != 1 { 657 printcreatedby1(f, pc) 658 } 659 } 660 661 func printcreatedby1(f funcInfo, pc uintptr) { 662 print("created by ", funcname(f), "\n") 663 tracepc := pc // back up to CALL instruction for funcline. 664 if pc > f.entry { 665 tracepc -= sys.PCQuantum 666 } 667 file, line := funcline(f, tracepc) 668 print("\t", file, ":", line) 669 if pc > f.entry { 670 print(" +", hex(pc-f.entry)) 671 } 672 print("\n") 673 } 674 675 func traceback(pc, sp, lr uintptr, gp *g) { 676 traceback1(pc, sp, lr, gp, 0) 677 } 678 679 // tracebacktrap is like traceback but expects that the PC and SP were obtained 680 // from a trap, not from gp->sched or gp->syscallpc/gp->syscallsp or getcallerpc/getcallersp. 681 // Because they are from a trap instead of from a saved pair, 682 // the initial PC must not be rewound to the previous instruction. 683 // (All the saved pairs record a PC that is a return address, so we 684 // rewind it into the CALL instruction.) 685 // If gp.m.libcall{g,pc,sp} information is available, it uses that information in preference to 686 // the pc/sp/lr passed in. 687 func tracebacktrap(pc, sp, lr uintptr, gp *g) { 688 if gp.m.libcallsp != 0 { 689 // We're in C code somewhere, traceback from the saved position. 690 traceback1(gp.m.libcallpc, gp.m.libcallsp, 0, gp.m.libcallg.ptr(), 0) 691 return 692 } 693 traceback1(pc, sp, lr, gp, _TraceTrap) 694 } 695 696 func traceback1(pc, sp, lr uintptr, gp *g, flags uint) { 697 // If the goroutine is in cgo, and we have a cgo traceback, print that. 698 if iscgo && gp.m != nil && gp.m.ncgo > 0 && gp.syscallsp != 0 && gp.m.cgoCallers != nil && gp.m.cgoCallers[0] != 0 { 699 // Lock cgoCallers so that a signal handler won't 700 // change it, copy the array, reset it, unlock it. 701 // We are locked to the thread and are not running 702 // concurrently with a signal handler. 703 // We just have to stop a signal handler from interrupting 704 // in the middle of our copy. 705 atomic.Store(&gp.m.cgoCallersUse, 1) 706 cgoCallers := *gp.m.cgoCallers 707 gp.m.cgoCallers[0] = 0 708 atomic.Store(&gp.m.cgoCallersUse, 0) 709 710 printCgoTraceback(&cgoCallers) 711 } 712 713 var n int 714 if readgstatus(gp)&^_Gscan == _Gsyscall { 715 // Override registers if blocked in system call. 716 pc = gp.syscallpc 717 sp = gp.syscallsp 718 flags &^= _TraceTrap 719 } 720 // Print traceback. By default, omits runtime frames. 721 // If that means we print nothing at all, repeat forcing all frames printed. 722 n = gentraceback(pc, sp, lr, gp, 0, nil, _TracebackMaxFrames, nil, nil, flags) 723 if n == 0 && (flags&_TraceRuntimeFrames) == 0 { 724 n = gentraceback(pc, sp, lr, gp, 0, nil, _TracebackMaxFrames, nil, nil, flags|_TraceRuntimeFrames) 725 } 726 if n == _TracebackMaxFrames { 727 print("...additional frames elided...\n") 728 } 729 printcreatedby(gp) 730 731 if gp.ancestors == nil { 732 return 733 } 734 for _, ancestor := range *gp.ancestors { 735 printAncestorTraceback(ancestor) 736 } 737 } 738 739 // printAncestorTraceback prints the traceback of the given ancestor. 740 // TODO: Unify this with gentraceback and CallersFrames. 741 func printAncestorTraceback(ancestor ancestorInfo) { 742 print("[originating from goroutine ", ancestor.goid, "]:\n") 743 for fidx, pc := range ancestor.pcs { 744 f := findfunc(pc) // f previously validated 745 if showfuncinfo(f, fidx == 0, funcID_normal, funcID_normal) { 746 printAncestorTracebackFuncInfo(f, pc) 747 } 748 } 749 if len(ancestor.pcs) == _TracebackMaxFrames { 750 print("...additional frames elided...\n") 751 } 752 // Show what created goroutine, except main goroutine (goid 1). 753 f := findfunc(ancestor.gopc) 754 if f.valid() && showfuncinfo(f, false, funcID_normal, funcID_normal) && ancestor.goid != 1 { 755 printcreatedby1(f, ancestor.gopc) 756 } 757 } 758 759 // printAncestorTraceback prints the given function info at a given pc 760 // within an ancestor traceback. The precision of this info is reduced 761 // due to only have access to the pcs at the time of the caller 762 // goroutine being created. 763 func printAncestorTracebackFuncInfo(f funcInfo, pc uintptr) { 764 name := funcname(f) 765 if inldata := funcdata(f, _FUNCDATA_InlTree); inldata != nil { 766 inltree := (*[1 << 20]inlinedCall)(inldata) 767 ix := pcdatavalue(f, _PCDATA_InlTreeIndex, pc, nil) 768 if ix >= 0 { 769 name = funcnameFromNameoff(f, inltree[ix].func_) 770 } 771 } 772 file, line := funcline(f, pc) 773 if name == "runtime.gopanic" { 774 name = "panic" 775 } 776 print(name, "(...)\n") 777 print("\t", file, ":", line) 778 if pc > f.entry { 779 print(" +", hex(pc-f.entry)) 780 } 781 print("\n") 782 } 783 784 func callers(skip int, pcbuf []uintptr) int { 785 sp := getcallersp() 786 pc := getcallerpc() 787 gp := getg() 788 var n int 789 systemstack(func() { 790 n = gentraceback(pc, sp, 0, gp, skip, &pcbuf[0], len(pcbuf), nil, nil, 0) 791 }) 792 return n 793 } 794 795 func gcallers(gp *g, skip int, pcbuf []uintptr) int { 796 return gentraceback(^uintptr(0), ^uintptr(0), 0, gp, skip, &pcbuf[0], len(pcbuf), nil, nil, 0) 797 } 798 799 // showframe reports whether the frame with the given characteristics should 800 // be printed during a traceback. 801 func showframe(f funcInfo, gp *g, firstFrame bool, funcID, childID funcID) bool { 802 g := getg() 803 if g.m.throwing > 0 && gp != nil && (gp == g.m.curg || gp == g.m.caughtsig.ptr()) { 804 return true 805 } 806 return showfuncinfo(f, firstFrame, funcID, childID) 807 } 808 809 // showfuncinfo reports whether a function with the given characteristics should 810 // be printed during a traceback. 811 func showfuncinfo(f funcInfo, firstFrame bool, funcID, childID funcID) bool { 812 level, _, _ := gotraceback() 813 if level > 1 { 814 // Show all frames. 815 return true 816 } 817 818 if !f.valid() { 819 return false 820 } 821 822 if funcID == funcID_wrapper && elideWrapperCalling(childID) { 823 return false 824 } 825 826 name := funcname(f) 827 828 // Special case: always show runtime.gopanic frame 829 // in the middle of a stack trace, so that we can 830 // see the boundary between ordinary code and 831 // panic-induced deferred code. 832 // See golang.org/issue/5832. 833 if name == "runtime.gopanic" && !firstFrame { 834 return true 835 } 836 837 return contains(name, ".") && (!hasPrefix(name, "runtime.") || isExportedRuntime(name)) 838 } 839 840 // isExportedRuntime reports whether name is an exported runtime function. 841 // It is only for runtime functions, so ASCII A-Z is fine. 842 func isExportedRuntime(name string) bool { 843 const n = len("runtime.") 844 return len(name) > n && name[:n] == "runtime." && 'A' <= name[n] && name[n] <= 'Z' 845 } 846 847 // elideWrapperCalling reports whether a wrapper function that called 848 // function id should be elided from stack traces. 849 func elideWrapperCalling(id funcID) bool { 850 // If the wrapper called a panic function instead of the 851 // wrapped function, we want to include it in stacks. 852 return !(id == funcID_gopanic || id == funcID_sigpanic || id == funcID_panicwrap) 853 } 854 855 var gStatusStrings = [...]string{ 856 _Gidle: "idle", 857 _Grunnable: "runnable", 858 _Grunning: "running", 859 _Gsyscall: "syscall", 860 _Gwaiting: "waiting", 861 _Gdead: "dead", 862 _Gcopystack: "copystack", 863 } 864 865 func goroutineheader(gp *g) { 866 gpstatus := readgstatus(gp) 867 868 isScan := gpstatus&_Gscan != 0 869 gpstatus &^= _Gscan // drop the scan bit 870 871 // Basic string status 872 var status string 873 if 0 <= gpstatus && gpstatus < uint32(len(gStatusStrings)) { 874 status = gStatusStrings[gpstatus] 875 } else { 876 status = "???" 877 } 878 879 // Override. 880 if gpstatus == _Gwaiting && gp.waitreason != waitReasonZero { 881 status = gp.waitreason.String() 882 } 883 884 // approx time the G is blocked, in minutes 885 var waitfor int64 886 if (gpstatus == _Gwaiting || gpstatus == _Gsyscall) && gp.waitsince != 0 { 887 waitfor = (nanotime() - gp.waitsince) / 60e9 888 } 889 print("goroutine ", gp.goid, " [", status) 890 if isScan { 891 print(" (scan)") 892 } 893 if waitfor >= 1 { 894 print(", ", waitfor, " minutes") 895 } 896 if gp.lockedm != 0 { 897 print(", locked to thread") 898 } 899 print("]:\n") 900 } 901 902 func tracebackothers(me *g) { 903 level, _, _ := gotraceback() 904 905 // Show the current goroutine first, if we haven't already. 906 g := getg() 907 gp := g.m.curg 908 if gp != nil && gp != me { 909 print("\n") 910 goroutineheader(gp) 911 traceback(^uintptr(0), ^uintptr(0), 0, gp) 912 } 913 914 lock(&allglock) 915 for _, gp := range allgs { 916 if gp == me || gp == g.m.curg || readgstatus(gp) == _Gdead || isSystemGoroutine(gp, false) && level < 2 { 917 continue 918 } 919 print("\n") 920 goroutineheader(gp) 921 // Note: gp.m == g.m occurs when tracebackothers is 922 // called from a signal handler initiated during a 923 // systemstack call. The original G is still in the 924 // running state, and we want to print its stack. 925 if gp.m != g.m && readgstatus(gp)&^_Gscan == _Grunning { 926 print("\tgoroutine running on other thread; stack unavailable\n") 927 printcreatedby(gp) 928 } else { 929 traceback(^uintptr(0), ^uintptr(0), 0, gp) 930 } 931 } 932 unlock(&allglock) 933 } 934 935 // tracebackHexdump hexdumps part of stk around frame.sp and frame.fp 936 // for debugging purposes. If the address bad is included in the 937 // hexdumped range, it will mark it as well. 938 func tracebackHexdump(stk stack, frame *stkframe, bad uintptr) { 939 const expand = 32 * sys.PtrSize 940 const maxExpand = 256 * sys.PtrSize 941 // Start around frame.sp. 942 lo, hi := frame.sp, frame.sp 943 // Expand to include frame.fp. 944 if frame.fp != 0 && frame.fp < lo { 945 lo = frame.fp 946 } 947 if frame.fp != 0 && frame.fp > hi { 948 hi = frame.fp 949 } 950 // Expand a bit more. 951 lo, hi = lo-expand, hi+expand 952 // But don't go too far from frame.sp. 953 if lo < frame.sp-maxExpand { 954 lo = frame.sp - maxExpand 955 } 956 if hi > frame.sp+maxExpand { 957 hi = frame.sp + maxExpand 958 } 959 // And don't go outside the stack bounds. 960 if lo < stk.lo { 961 lo = stk.lo 962 } 963 if hi > stk.hi { 964 hi = stk.hi 965 } 966 967 // Print the hex dump. 968 print("stack: frame={sp:", hex(frame.sp), ", fp:", hex(frame.fp), "} stack=[", hex(stk.lo), ",", hex(stk.hi), ")\n") 969 hexdumpWords(lo, hi, func(p uintptr) byte { 970 switch p { 971 case frame.fp: 972 return '>' 973 case frame.sp: 974 return '<' 975 case bad: 976 return '!' 977 } 978 return 0 979 }) 980 } 981 982 // Does f mark the top of a goroutine stack? 983 func topofstack(f funcInfo, g0 bool) bool { 984 return f.funcID == funcID_goexit || 985 f.funcID == funcID_mstart || 986 f.funcID == funcID_mcall || 987 f.funcID == funcID_morestack || 988 f.funcID == funcID_rt0_go || 989 f.funcID == funcID_externalthreadhandler || 990 // asmcgocall is TOS on the system stack because it 991 // switches to the system stack, but in this case we 992 // can come back to the regular stack and still want 993 // to be able to unwind through the call that appeared 994 // on the regular stack. 995 (g0 && f.funcID == funcID_asmcgocall) 996 } 997 998 // isSystemGoroutine reports whether the goroutine g must be omitted 999 // in stack dumps and deadlock detector. This is any goroutine that 1000 // starts at a runtime.* entry point, except for runtime.main and 1001 // sometimes runtime.runfinq. 1002 // 1003 // If fixed is true, any goroutine that can vary between user and 1004 // system (that is, the finalizer goroutine) is considered a user 1005 // goroutine. 1006 func isSystemGoroutine(gp *g, fixed bool) bool { 1007 // Keep this in sync with cmd/trace/trace.go:isSystemGoroutine. 1008 f := findfunc(gp.startpc) 1009 if !f.valid() { 1010 return false 1011 } 1012 if f.funcID == funcID_runtime_main { 1013 return false 1014 } 1015 if f.funcID == funcID_runfinq { 1016 // We include the finalizer goroutine if it's calling 1017 // back into user code. 1018 if fixed { 1019 // This goroutine can vary. In fixed mode, 1020 // always consider it a user goroutine. 1021 return false 1022 } 1023 return !fingRunning 1024 } 1025 return hasPrefix(funcname(f), "runtime.") 1026 } 1027 1028 // SetCgoTraceback records three C functions to use to gather 1029 // traceback information from C code and to convert that traceback 1030 // information into symbolic information. These are used when printing 1031 // stack traces for a program that uses cgo. 1032 // 1033 // The traceback and context functions may be called from a signal 1034 // handler, and must therefore use only async-signal safe functions. 1035 // The symbolizer function may be called while the program is 1036 // crashing, and so must be cautious about using memory. None of the 1037 // functions may call back into Go. 1038 // 1039 // The context function will be called with a single argument, a 1040 // pointer to a struct: 1041 // 1042 // struct { 1043 // Context uintptr 1044 // } 1045 // 1046 // In C syntax, this struct will be 1047 // 1048 // struct { 1049 // uintptr_t Context; 1050 // }; 1051 // 1052 // If the Context field is 0, the context function is being called to 1053 // record the current traceback context. It should record in the 1054 // Context field whatever information is needed about the current 1055 // point of execution to later produce a stack trace, probably the 1056 // stack pointer and PC. In this case the context function will be 1057 // called from C code. 1058 // 1059 // If the Context field is not 0, then it is a value returned by a 1060 // previous call to the context function. This case is called when the 1061 // context is no longer needed; that is, when the Go code is returning 1062 // to its C code caller. This permits the context function to release 1063 // any associated resources. 1064 // 1065 // While it would be correct for the context function to record a 1066 // complete a stack trace whenever it is called, and simply copy that 1067 // out in the traceback function, in a typical program the context 1068 // function will be called many times without ever recording a 1069 // traceback for that context. Recording a complete stack trace in a 1070 // call to the context function is likely to be inefficient. 1071 // 1072 // The traceback function will be called with a single argument, a 1073 // pointer to a struct: 1074 // 1075 // struct { 1076 // Context uintptr 1077 // SigContext uintptr 1078 // Buf *uintptr 1079 // Max uintptr 1080 // } 1081 // 1082 // In C syntax, this struct will be 1083 // 1084 // struct { 1085 // uintptr_t Context; 1086 // uintptr_t SigContext; 1087 // uintptr_t* Buf; 1088 // uintptr_t Max; 1089 // }; 1090 // 1091 // The Context field will be zero to gather a traceback from the 1092 // current program execution point. In this case, the traceback 1093 // function will be called from C code. 1094 // 1095 // Otherwise Context will be a value previously returned by a call to 1096 // the context function. The traceback function should gather a stack 1097 // trace from that saved point in the program execution. The traceback 1098 // function may be called from an execution thread other than the one 1099 // that recorded the context, but only when the context is known to be 1100 // valid and unchanging. The traceback function may also be called 1101 // deeper in the call stack on the same thread that recorded the 1102 // context. The traceback function may be called multiple times with 1103 // the same Context value; it will usually be appropriate to cache the 1104 // result, if possible, the first time this is called for a specific 1105 // context value. 1106 // 1107 // If the traceback function is called from a signal handler on a Unix 1108 // system, SigContext will be the signal context argument passed to 1109 // the signal handler (a C ucontext_t* cast to uintptr_t). This may be 1110 // used to start tracing at the point where the signal occurred. If 1111 // the traceback function is not called from a signal handler, 1112 // SigContext will be zero. 1113 // 1114 // Buf is where the traceback information should be stored. It should 1115 // be PC values, such that Buf[0] is the PC of the caller, Buf[1] is 1116 // the PC of that function's caller, and so on. Max is the maximum 1117 // number of entries to store. The function should store a zero to 1118 // indicate the top of the stack, or that the caller is on a different 1119 // stack, presumably a Go stack. 1120 // 1121 // Unlike runtime.Callers, the PC values returned should, when passed 1122 // to the symbolizer function, return the file/line of the call 1123 // instruction. No additional subtraction is required or appropriate. 1124 // 1125 // On all platforms, the traceback function is invoked when a call from 1126 // Go to C to Go requests a stack trace. On linux/amd64, linux/ppc64le, 1127 // and freebsd/amd64, the traceback function is also invoked when a 1128 // signal is received by a thread that is executing a cgo call. The 1129 // traceback function should not make assumptions about when it is 1130 // called, as future versions of Go may make additional calls. 1131 // 1132 // The symbolizer function will be called with a single argument, a 1133 // pointer to a struct: 1134 // 1135 // struct { 1136 // PC uintptr // program counter to fetch information for 1137 // File *byte // file name (NUL terminated) 1138 // Lineno uintptr // line number 1139 // Func *byte // function name (NUL terminated) 1140 // Entry uintptr // function entry point 1141 // More uintptr // set non-zero if more info for this PC 1142 // Data uintptr // unused by runtime, available for function 1143 // } 1144 // 1145 // In C syntax, this struct will be 1146 // 1147 // struct { 1148 // uintptr_t PC; 1149 // char* File; 1150 // uintptr_t Lineno; 1151 // char* Func; 1152 // uintptr_t Entry; 1153 // uintptr_t More; 1154 // uintptr_t Data; 1155 // }; 1156 // 1157 // The PC field will be a value returned by a call to the traceback 1158 // function. 1159 // 1160 // The first time the function is called for a particular traceback, 1161 // all the fields except PC will be 0. The function should fill in the 1162 // other fields if possible, setting them to 0/nil if the information 1163 // is not available. The Data field may be used to store any useful 1164 // information across calls. The More field should be set to non-zero 1165 // if there is more information for this PC, zero otherwise. If More 1166 // is set non-zero, the function will be called again with the same 1167 // PC, and may return different information (this is intended for use 1168 // with inlined functions). If More is zero, the function will be 1169 // called with the next PC value in the traceback. When the traceback 1170 // is complete, the function will be called once more with PC set to 1171 // zero; this may be used to free any information. Each call will 1172 // leave the fields of the struct set to the same values they had upon 1173 // return, except for the PC field when the More field is zero. The 1174 // function must not keep a copy of the struct pointer between calls. 1175 // 1176 // When calling SetCgoTraceback, the version argument is the version 1177 // number of the structs that the functions expect to receive. 1178 // Currently this must be zero. 1179 // 1180 // The symbolizer function may be nil, in which case the results of 1181 // the traceback function will be displayed as numbers. If the 1182 // traceback function is nil, the symbolizer function will never be 1183 // called. The context function may be nil, in which case the 1184 // traceback function will only be called with the context field set 1185 // to zero. If the context function is nil, then calls from Go to C 1186 // to Go will not show a traceback for the C portion of the call stack. 1187 // 1188 // SetCgoTraceback should be called only once, ideally from an init function. 1189 func SetCgoTraceback(version int, traceback, context, symbolizer unsafe.Pointer) { 1190 if version != 0 { 1191 panic("unsupported version") 1192 } 1193 1194 if cgoTraceback != nil && cgoTraceback != traceback || 1195 cgoContext != nil && cgoContext != context || 1196 cgoSymbolizer != nil && cgoSymbolizer != symbolizer { 1197 panic("call SetCgoTraceback only once") 1198 } 1199 1200 cgoTraceback = traceback 1201 cgoContext = context 1202 cgoSymbolizer = symbolizer 1203 1204 // The context function is called when a C function calls a Go 1205 // function. As such it is only called by C code in runtime/cgo. 1206 if _cgo_set_context_function != nil { 1207 cgocall(_cgo_set_context_function, context) 1208 } 1209 } 1210 1211 var cgoTraceback unsafe.Pointer 1212 var cgoContext unsafe.Pointer 1213 var cgoSymbolizer unsafe.Pointer 1214 1215 // cgoTracebackArg is the type passed to cgoTraceback. 1216 type cgoTracebackArg struct { 1217 context uintptr 1218 sigContext uintptr 1219 buf *uintptr 1220 max uintptr 1221 } 1222 1223 // cgoContextArg is the type passed to the context function. 1224 type cgoContextArg struct { 1225 context uintptr 1226 } 1227 1228 // cgoSymbolizerArg is the type passed to cgoSymbolizer. 1229 type cgoSymbolizerArg struct { 1230 pc uintptr 1231 file *byte 1232 lineno uintptr 1233 funcName *byte 1234 entry uintptr 1235 more uintptr 1236 data uintptr 1237 } 1238 1239 // cgoTraceback prints a traceback of callers. 1240 func printCgoTraceback(callers *cgoCallers) { 1241 if cgoSymbolizer == nil { 1242 for _, c := range callers { 1243 if c == 0 { 1244 break 1245 } 1246 print("non-Go function at pc=", hex(c), "\n") 1247 } 1248 return 1249 } 1250 1251 var arg cgoSymbolizerArg 1252 for _, c := range callers { 1253 if c == 0 { 1254 break 1255 } 1256 printOneCgoTraceback(c, 0x7fffffff, &arg) 1257 } 1258 arg.pc = 0 1259 callCgoSymbolizer(&arg) 1260 } 1261 1262 // printOneCgoTraceback prints the traceback of a single cgo caller. 1263 // This can print more than one line because of inlining. 1264 // Returns the number of frames printed. 1265 func printOneCgoTraceback(pc uintptr, max int, arg *cgoSymbolizerArg) int { 1266 c := 0 1267 arg.pc = pc 1268 for c <= max { 1269 callCgoSymbolizer(arg) 1270 if arg.funcName != nil { 1271 // Note that we don't print any argument 1272 // information here, not even parentheses. 1273 // The symbolizer must add that if appropriate. 1274 println(gostringnocopy(arg.funcName)) 1275 } else { 1276 println("non-Go function") 1277 } 1278 print("\t") 1279 if arg.file != nil { 1280 print(gostringnocopy(arg.file), ":", arg.lineno, " ") 1281 } 1282 print("pc=", hex(pc), "\n") 1283 c++ 1284 if arg.more == 0 { 1285 break 1286 } 1287 } 1288 return c 1289 } 1290 1291 // callCgoSymbolizer calls the cgoSymbolizer function. 1292 func callCgoSymbolizer(arg *cgoSymbolizerArg) { 1293 call := cgocall 1294 if panicking > 0 || getg().m.curg != getg() { 1295 // We do not want to call into the scheduler when panicking 1296 // or when on the system stack. 1297 call = asmcgocall 1298 } 1299 if msanenabled { 1300 msanwrite(unsafe.Pointer(arg), unsafe.Sizeof(cgoSymbolizerArg{})) 1301 } 1302 call(cgoSymbolizer, noescape(unsafe.Pointer(arg))) 1303 } 1304 1305 // cgoContextPCs gets the PC values from a cgo traceback. 1306 func cgoContextPCs(ctxt uintptr, buf []uintptr) { 1307 if cgoTraceback == nil { 1308 return 1309 } 1310 call := cgocall 1311 if panicking > 0 || getg().m.curg != getg() { 1312 // We do not want to call into the scheduler when panicking 1313 // or when on the system stack. 1314 call = asmcgocall 1315 } 1316 arg := cgoTracebackArg{ 1317 context: ctxt, 1318 buf: (*uintptr)(noescape(unsafe.Pointer(&buf[0]))), 1319 max: uintptr(len(buf)), 1320 } 1321 if msanenabled { 1322 msanwrite(unsafe.Pointer(&arg), unsafe.Sizeof(arg)) 1323 } 1324 call(cgoTraceback, noescape(unsafe.Pointer(&arg))) 1325 } 1326
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