Source file src/runtime/traceback.go
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 "internal/bytealg" 9 "internal/goarch" 10 "runtime/internal/sys" 11 "unsafe" 12 ) 13 14 // The code in this file implements stack trace walking for all architectures. 15 // The most important fact about a given architecture is whether it uses a link register. 16 // On systems with link registers, the prologue for a non-leaf function stores the 17 // incoming value of LR at the bottom of the newly allocated stack frame. 18 // On systems without link registers (x86), the architecture pushes a return PC during 19 // the call instruction, so the return PC ends up above the stack frame. 20 // In this file, the return PC is always called LR, no matter how it was found. 21 22 const usesLR = sys.MinFrameSize > 0 23 24 // Generic traceback. Handles runtime stack prints (pcbuf == nil), 25 // the runtime.Callers function (pcbuf != nil), as well as the garbage 26 // collector (callback != nil). A little clunky to merge these, but avoids 27 // duplicating the code and all its subtlety. 28 // 29 // The skip argument is only valid with pcbuf != nil and counts the number 30 // of logical frames to skip rather than physical frames (with inlining, a 31 // PC in pcbuf can represent multiple calls). 32 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 { 33 if skip > 0 && callback != nil { 34 throw("gentraceback callback cannot be used with non-zero skip") 35 } 36 37 // Don't call this "g"; it's too easy get "g" and "gp" confused. 38 if ourg := getg(); ourg == gp && ourg == ourg.m.curg { 39 // The starting sp has been passed in as a uintptr, and the caller may 40 // have other uintptr-typed stack references as well. 41 // If during one of the calls that got us here or during one of the 42 // callbacks below the stack must be grown, all these uintptr references 43 // to the stack will not be updated, and gentraceback will continue 44 // to inspect the old stack memory, which may no longer be valid. 45 // Even if all the variables were updated correctly, it is not clear that 46 // we want to expose a traceback that begins on one stack and ends 47 // on another stack. That could confuse callers quite a bit. 48 // Instead, we require that gentraceback and any other function that 49 // accepts an sp for the current goroutine (typically obtained by 50 // calling getcallersp) must not run on that goroutine's stack but 51 // instead on the g0 stack. 52 throw("gentraceback cannot trace user goroutine on its own stack") 53 } 54 level, _, _ := gotraceback() 55 56 if pc0 == ^uintptr(0) && sp0 == ^uintptr(0) { // Signal to fetch saved values from gp. 57 if gp.syscallsp != 0 { 58 pc0 = gp.syscallpc 59 sp0 = gp.syscallsp 60 if usesLR { 61 lr0 = 0 62 } 63 } else { 64 pc0 = gp.sched.pc 65 sp0 = gp.sched.sp 66 if usesLR { 67 lr0 = gp.sched.lr 68 } 69 } 70 } 71 72 nprint := 0 73 var frame stkframe 74 frame.pc = pc0 75 frame.sp = sp0 76 if usesLR { 77 frame.lr = lr0 78 } 79 waspanic := false 80 cgoCtxt := gp.cgoCtxt 81 stack := gp.stack 82 printing := pcbuf == nil && callback == nil 83 84 // If the PC is zero, it's likely a nil function call. 85 // Start in the caller's frame. 86 if frame.pc == 0 { 87 if usesLR { 88 frame.pc = *(*uintptr)(unsafe.Pointer(frame.sp)) 89 frame.lr = 0 90 } else { 91 frame.pc = uintptr(*(*uintptr)(unsafe.Pointer(frame.sp))) 92 frame.sp += goarch.PtrSize 93 } 94 } 95 96 // runtime/internal/atomic functions call into kernel helpers on 97 // arm < 7. See runtime/internal/atomic/sys_linux_arm.s. 98 // 99 // Start in the caller's frame. 100 if GOARCH == "arm" && goarm < 7 && GOOS == "linux" && frame.pc&0xffff0000 == 0xffff0000 { 101 // Note that the calls are simple BL without pushing the return 102 // address, so we use LR directly. 103 // 104 // The kernel helpers are frameless leaf functions, so SP and 105 // LR are not touched. 106 frame.pc = frame.lr 107 frame.lr = 0 108 } 109 110 f := findfunc(frame.pc) 111 if !f.valid() { 112 if callback != nil || printing { 113 print("runtime: g ", gp.goid, ": unknown pc ", hex(frame.pc), "\n") 114 tracebackHexdump(stack, &frame, 0) 115 } 116 if callback != nil { 117 throw("unknown pc") 118 } 119 return 0 120 } 121 frame.fn = f 122 123 var cache pcvalueCache 124 125 lastFuncID := funcID_normal 126 n := 0 127 for n < max { 128 // Typically: 129 // pc is the PC of the running function. 130 // sp is the stack pointer at that program counter. 131 // fp is the frame pointer (caller's stack pointer) at that program counter, or nil if unknown. 132 // stk is the stack containing sp. 133 // The caller's program counter is lr, unless lr is zero, in which case it is *(uintptr*)sp. 134 f = frame.fn 135 if f.pcsp == 0 { 136 // No frame information, must be external function, like race support. 137 // See golang.org/issue/13568. 138 break 139 } 140 141 // Compute function info flags. 142 flag := f.flag 143 if f.funcID == funcID_cgocallback { 144 // cgocallback does write SP to switch from the g0 to the curg stack, 145 // but it carefully arranges that during the transition BOTH stacks 146 // have cgocallback frame valid for unwinding through. 147 // So we don't need to exclude it with the other SP-writing functions. 148 flag &^= funcFlag_SPWRITE 149 } 150 if frame.pc == pc0 && frame.sp == sp0 && pc0 == gp.syscallpc && sp0 == gp.syscallsp { 151 // Some Syscall functions write to SP, but they do so only after 152 // saving the entry PC/SP using entersyscall. 153 // Since we are using the entry PC/SP, the later SP write doesn't matter. 154 flag &^= funcFlag_SPWRITE 155 } 156 157 // Found an actual function. 158 // Derive frame pointer and link register. 159 if frame.fp == 0 { 160 // Jump over system stack transitions. If we're on g0 and there's a user 161 // goroutine, try to jump. Otherwise this is a regular call. 162 // We also defensively check that this won't switch M's on us, 163 // which could happen at critical points in the scheduler. 164 // This ensures gp.m doesn't change from a stack jump. 165 if flags&_TraceJumpStack != 0 && gp == gp.m.g0 && gp.m.curg != nil && gp.m.curg.m == gp.m { 166 switch f.funcID { 167 case funcID_morestack: 168 // morestack does not return normally -- newstack() 169 // gogo's to curg.sched. Match that. 170 // This keeps morestack() from showing up in the backtrace, 171 // but that makes some sense since it'll never be returned 172 // to. 173 gp = gp.m.curg 174 frame.pc = gp.sched.pc 175 frame.fn = findfunc(frame.pc) 176 f = frame.fn 177 flag = f.flag 178 frame.lr = gp.sched.lr 179 frame.sp = gp.sched.sp 180 stack = gp.stack 181 cgoCtxt = gp.cgoCtxt 182 case funcID_systemstack: 183 // systemstack returns normally, so just follow the 184 // stack transition. 185 if usesLR && funcspdelta(f, frame.pc, &cache) == 0 { 186 // We're at the function prologue and the stack 187 // switch hasn't happened, or epilogue where we're 188 // about to return. Just unwind normally. 189 // Do this only on LR machines because on x86 190 // systemstack doesn't have an SP delta (the CALL 191 // instruction opens the frame), therefore no way 192 // to check. 193 flag &^= funcFlag_SPWRITE 194 break 195 } 196 gp = gp.m.curg 197 frame.sp = gp.sched.sp 198 stack = gp.stack 199 cgoCtxt = gp.cgoCtxt 200 flag &^= funcFlag_SPWRITE 201 } 202 } 203 frame.fp = frame.sp + uintptr(funcspdelta(f, frame.pc, &cache)) 204 if !usesLR { 205 // On x86, call instruction pushes return PC before entering new function. 206 frame.fp += goarch.PtrSize 207 } 208 } 209 var flr funcInfo 210 if flag&funcFlag_TOPFRAME != 0 { 211 // This function marks the top of the stack. Stop the traceback. 212 frame.lr = 0 213 flr = funcInfo{} 214 } else if flag&funcFlag_SPWRITE != 0 && (callback == nil || n > 0) { 215 // The function we are in does a write to SP that we don't know 216 // how to encode in the spdelta table. Examples include context 217 // switch routines like runtime.gogo but also any code that switches 218 // to the g0 stack to run host C code. Since we can't reliably unwind 219 // the SP (we might not even be on the stack we think we are), 220 // we stop the traceback here. 221 // This only applies for profiling signals (callback == nil). 222 // 223 // For a GC stack traversal (callback != nil), we should only see 224 // a function when it has voluntarily preempted itself on entry 225 // during the stack growth check. In that case, the function has 226 // not yet had a chance to do any writes to SP and is safe to unwind. 227 // isAsyncSafePoint does not allow assembly functions to be async preempted, 228 // and preemptPark double-checks that SPWRITE functions are not async preempted. 229 // So for GC stack traversal we leave things alone (this if body does not execute for n == 0) 230 // at the bottom frame of the stack. But farther up the stack we'd better not 231 // find any. 232 if callback != nil { 233 println("traceback: unexpected SPWRITE function", funcname(f)) 234 throw("traceback") 235 } 236 frame.lr = 0 237 flr = funcInfo{} 238 } else { 239 var lrPtr uintptr 240 if usesLR { 241 if n == 0 && frame.sp < frame.fp || frame.lr == 0 { 242 lrPtr = frame.sp 243 frame.lr = *(*uintptr)(unsafe.Pointer(lrPtr)) 244 } 245 } else { 246 if frame.lr == 0 { 247 lrPtr = frame.fp - goarch.PtrSize 248 frame.lr = uintptr(*(*uintptr)(unsafe.Pointer(lrPtr))) 249 } 250 } 251 flr = findfunc(frame.lr) 252 if !flr.valid() { 253 // This happens if you get a profiling interrupt at just the wrong time. 254 // In that context it is okay to stop early. 255 // But if callback is set, we're doing a garbage collection and must 256 // get everything, so crash loudly. 257 doPrint := printing 258 if doPrint && gp.m.incgo && f.funcID == funcID_sigpanic { 259 // We can inject sigpanic 260 // calls directly into C code, 261 // in which case we'll see a C 262 // return PC. Don't complain. 263 doPrint = false 264 } 265 if callback != nil || doPrint { 266 print("runtime: g ", gp.goid, ": unexpected return pc for ", funcname(f), " called from ", hex(frame.lr), "\n") 267 tracebackHexdump(stack, &frame, lrPtr) 268 } 269 if callback != nil { 270 throw("unknown caller pc") 271 } 272 } 273 } 274 275 frame.varp = frame.fp 276 if !usesLR { 277 // On x86, call instruction pushes return PC before entering new function. 278 frame.varp -= goarch.PtrSize 279 } 280 281 // For architectures with frame pointers, if there's 282 // a frame, then there's a saved frame pointer here. 283 // 284 // NOTE: This code is not as general as it looks. 285 // On x86, the ABI is to save the frame pointer word at the 286 // top of the stack frame, so we have to back down over it. 287 // On arm64, the frame pointer should be at the bottom of 288 // the stack (with R29 (aka FP) = RSP), in which case we would 289 // not want to do the subtraction here. But we started out without 290 // any frame pointer, and when we wanted to add it, we didn't 291 // want to break all the assembly doing direct writes to 8(RSP) 292 // to set the first parameter to a called function. 293 // So we decided to write the FP link *below* the stack pointer 294 // (with R29 = RSP - 8 in Go functions). 295 // This is technically ABI-compatible but not standard. 296 // And it happens to end up mimicking the x86 layout. 297 // Other architectures may make different decisions. 298 if frame.varp > frame.sp && framepointer_enabled { 299 frame.varp -= goarch.PtrSize 300 } 301 302 frame.argp = frame.fp + sys.MinFrameSize 303 304 // Determine frame's 'continuation PC', where it can continue. 305 // Normally this is the return address on the stack, but if sigpanic 306 // is immediately below this function on the stack, then the frame 307 // stopped executing due to a trap, and frame.pc is probably not 308 // a safe point for looking up liveness information. In this panicking case, 309 // the function either doesn't return at all (if it has no defers or if the 310 // defers do not recover) or it returns from one of the calls to 311 // deferproc a second time (if the corresponding deferred func recovers). 312 // In the latter case, use a deferreturn call site as the continuation pc. 313 frame.continpc = frame.pc 314 if waspanic { 315 if frame.fn.deferreturn != 0 { 316 frame.continpc = frame.fn.entry() + uintptr(frame.fn.deferreturn) + 1 317 // Note: this may perhaps keep return variables alive longer than 318 // strictly necessary, as we are using "function has a defer statement" 319 // as a proxy for "function actually deferred something". It seems 320 // to be a minor drawback. (We used to actually look through the 321 // gp._defer for a defer corresponding to this function, but that 322 // is hard to do with defer records on the stack during a stack copy.) 323 // Note: the +1 is to offset the -1 that 324 // stack.go:getStackMap does to back up a return 325 // address make sure the pc is in the CALL instruction. 326 } else { 327 frame.continpc = 0 328 } 329 } 330 331 if callback != nil { 332 if !callback((*stkframe)(noescape(unsafe.Pointer(&frame))), v) { 333 return n 334 } 335 } 336 337 if pcbuf != nil { 338 pc := frame.pc 339 // backup to CALL instruction to read inlining info (same logic as below) 340 tracepc := pc 341 // Normally, pc is a return address. In that case, we want to look up 342 // file/line information using pc-1, because that is the pc of the 343 // call instruction (more precisely, the last byte of the call instruction). 344 // Callers expect the pc buffer to contain return addresses and do the 345 // same -1 themselves, so we keep pc unchanged. 346 // When the pc is from a signal (e.g. profiler or segv) then we want 347 // to look up file/line information using pc, and we store pc+1 in the 348 // pc buffer so callers can unconditionally subtract 1 before looking up. 349 // See issue 34123. 350 // The pc can be at function entry when the frame is initialized without 351 // actually running code, like runtime.mstart. 352 if (n == 0 && flags&_TraceTrap != 0) || waspanic || pc == f.entry() { 353 pc++ 354 } else { 355 tracepc-- 356 } 357 358 // If there is inlining info, record the inner frames. 359 if inldata := funcdata(f, _FUNCDATA_InlTree); inldata != nil { 360 inltree := (*[1 << 20]inlinedCall)(inldata) 361 for { 362 ix := pcdatavalue(f, _PCDATA_InlTreeIndex, tracepc, &cache) 363 if ix < 0 { 364 break 365 } 366 if inltree[ix].funcID == funcID_wrapper && elideWrapperCalling(lastFuncID) { 367 // ignore wrappers 368 } else if skip > 0 { 369 skip-- 370 } else if n < max { 371 (*[1 << 20]uintptr)(unsafe.Pointer(pcbuf))[n] = pc 372 n++ 373 } 374 lastFuncID = inltree[ix].funcID 375 // Back up to an instruction in the "caller". 376 tracepc = frame.fn.entry() + uintptr(inltree[ix].parentPc) 377 pc = tracepc + 1 378 } 379 } 380 // Record the main frame. 381 if f.funcID == funcID_wrapper && elideWrapperCalling(lastFuncID) { 382 // Ignore wrapper functions (except when they trigger panics). 383 } else if skip > 0 { 384 skip-- 385 } else if n < max { 386 (*[1 << 20]uintptr)(unsafe.Pointer(pcbuf))[n] = pc 387 n++ 388 } 389 lastFuncID = f.funcID 390 n-- // offset n++ below 391 } 392 393 if printing { 394 // assume skip=0 for printing. 395 // 396 // Never elide wrappers if we haven't printed 397 // any frames. And don't elide wrappers that 398 // called panic rather than the wrapped 399 // function. Otherwise, leave them out. 400 401 // backup to CALL instruction to read inlining info (same logic as below) 402 tracepc := frame.pc 403 if (n > 0 || flags&_TraceTrap == 0) && frame.pc > f.entry() && !waspanic { 404 tracepc-- 405 } 406 // If there is inlining info, print the inner frames. 407 if inldata := funcdata(f, _FUNCDATA_InlTree); inldata != nil { 408 inltree := (*[1 << 20]inlinedCall)(inldata) 409 var inlFunc _func 410 inlFuncInfo := funcInfo{&inlFunc, f.datap} 411 for { 412 ix := pcdatavalue(f, _PCDATA_InlTreeIndex, tracepc, nil) 413 if ix < 0 { 414 break 415 } 416 417 // Create a fake _func for the 418 // inlined function. 419 inlFunc.nameOff = inltree[ix].nameOff 420 inlFunc.funcID = inltree[ix].funcID 421 inlFunc.startLine = inltree[ix].startLine 422 423 if (flags&_TraceRuntimeFrames) != 0 || showframe(inlFuncInfo, gp, nprint == 0, inlFuncInfo.funcID, lastFuncID) { 424 name := funcname(inlFuncInfo) 425 file, line := funcline(f, tracepc) 426 print(name, "(...)\n") 427 print("\t", file, ":", line, "\n") 428 nprint++ 429 } 430 lastFuncID = inltree[ix].funcID 431 // Back up to an instruction in the "caller". 432 tracepc = frame.fn.entry() + uintptr(inltree[ix].parentPc) 433 } 434 } 435 if (flags&_TraceRuntimeFrames) != 0 || showframe(f, gp, nprint == 0, f.funcID, lastFuncID) { 436 // Print during crash. 437 // main(0x1, 0x2, 0x3) 438 // /home/rsc/go/src/runtime/x.go:23 +0xf 439 // 440 name := funcname(f) 441 file, line := funcline(f, tracepc) 442 if name == "runtime.gopanic" { 443 name = "panic" 444 } 445 print(name, "(") 446 argp := unsafe.Pointer(frame.argp) 447 printArgs(f, argp, tracepc) 448 print(")\n") 449 print("\t", file, ":", line) 450 if frame.pc > f.entry() { 451 print(" +", hex(frame.pc-f.entry())) 452 } 453 if gp.m != nil && gp.m.throwing >= throwTypeRuntime && gp == gp.m.curg || level >= 2 { 454 print(" fp=", hex(frame.fp), " sp=", hex(frame.sp), " pc=", hex(frame.pc)) 455 } 456 print("\n") 457 nprint++ 458 } 459 lastFuncID = f.funcID 460 } 461 n++ 462 463 if f.funcID == funcID_cgocallback && len(cgoCtxt) > 0 { 464 ctxt := cgoCtxt[len(cgoCtxt)-1] 465 cgoCtxt = cgoCtxt[:len(cgoCtxt)-1] 466 467 // skip only applies to Go frames. 468 // callback != nil only used when we only care 469 // about Go frames. 470 if skip == 0 && callback == nil { 471 n = tracebackCgoContext(pcbuf, printing, ctxt, n, max) 472 } 473 } 474 475 waspanic = f.funcID == funcID_sigpanic 476 injectedCall := waspanic || f.funcID == funcID_asyncPreempt || f.funcID == funcID_debugCallV2 477 478 // Do not unwind past the bottom of the stack. 479 if !flr.valid() { 480 break 481 } 482 483 if frame.pc == frame.lr && frame.sp == frame.fp { 484 // If the next frame is identical to the current frame, we cannot make progress. 485 print("runtime: traceback stuck. pc=", hex(frame.pc), " sp=", hex(frame.sp), "\n") 486 tracebackHexdump(stack, &frame, frame.sp) 487 throw("traceback stuck") 488 } 489 490 // Unwind to next frame. 491 frame.fn = flr 492 frame.pc = frame.lr 493 frame.lr = 0 494 frame.sp = frame.fp 495 frame.fp = 0 496 497 // On link register architectures, sighandler saves the LR on stack 498 // before faking a call. 499 if usesLR && injectedCall { 500 x := *(*uintptr)(unsafe.Pointer(frame.sp)) 501 frame.sp += alignUp(sys.MinFrameSize, sys.StackAlign) 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 // printArgs prints function arguments in traceback. 566 func printArgs(f funcInfo, argp unsafe.Pointer, pc uintptr) { 567 // The "instruction" of argument printing is encoded in _FUNCDATA_ArgInfo. 568 // See cmd/compile/internal/ssagen.emitArgInfo for the description of the 569 // encoding. 570 // These constants need to be in sync with the compiler. 571 const ( 572 _endSeq = 0xff 573 _startAgg = 0xfe 574 _endAgg = 0xfd 575 _dotdotdot = 0xfc 576 _offsetTooLarge = 0xfb 577 ) 578 579 const ( 580 limit = 10 // print no more than 10 args/components 581 maxDepth = 5 // no more than 5 layers of nesting 582 maxLen = (maxDepth*3+2)*limit + 1 // max length of _FUNCDATA_ArgInfo (see the compiler side for reasoning) 583 ) 584 585 p := (*[maxLen]uint8)(funcdata(f, _FUNCDATA_ArgInfo)) 586 if p == nil { 587 return 588 } 589 590 liveInfo := funcdata(f, _FUNCDATA_ArgLiveInfo) 591 liveIdx := pcdatavalue(f, _PCDATA_ArgLiveIndex, pc, nil) 592 startOffset := uint8(0xff) // smallest offset that needs liveness info (slots with a lower offset is always live) 593 if liveInfo != nil { 594 startOffset = *(*uint8)(liveInfo) 595 } 596 597 isLive := func(off, slotIdx uint8) bool { 598 if liveInfo == nil || liveIdx <= 0 { 599 return true // no liveness info, always live 600 } 601 if off < startOffset { 602 return true 603 } 604 bits := *(*uint8)(add(liveInfo, uintptr(liveIdx)+uintptr(slotIdx/8))) 605 return bits&(1<<(slotIdx%8)) != 0 606 } 607 608 print1 := func(off, sz, slotIdx uint8) { 609 x := readUnaligned64(add(argp, uintptr(off))) 610 // mask out irrelevant bits 611 if sz < 8 { 612 shift := 64 - sz*8 613 if goarch.BigEndian { 614 x = x >> shift 615 } else { 616 x = x << shift >> shift 617 } 618 } 619 print(hex(x)) 620 if !isLive(off, slotIdx) { 621 print("?") 622 } 623 } 624 625 start := true 626 printcomma := func() { 627 if !start { 628 print(", ") 629 } 630 } 631 pi := 0 632 slotIdx := uint8(0) // register arg spill slot index 633 printloop: 634 for { 635 o := p[pi] 636 pi++ 637 switch o { 638 case _endSeq: 639 break printloop 640 case _startAgg: 641 printcomma() 642 print("{") 643 start = true 644 continue 645 case _endAgg: 646 print("}") 647 case _dotdotdot: 648 printcomma() 649 print("...") 650 case _offsetTooLarge: 651 printcomma() 652 print("_") 653 default: 654 printcomma() 655 sz := p[pi] 656 pi++ 657 print1(o, sz, slotIdx) 658 if o >= startOffset { 659 slotIdx++ 660 } 661 } 662 start = false 663 } 664 } 665 666 // tracebackCgoContext handles tracing back a cgo context value, from 667 // the context argument to setCgoTraceback, for the gentraceback 668 // function. It returns the new value of n. 669 func tracebackCgoContext(pcbuf *uintptr, printing bool, ctxt uintptr, n, max int) int { 670 var cgoPCs [32]uintptr 671 cgoContextPCs(ctxt, cgoPCs[:]) 672 var arg cgoSymbolizerArg 673 anySymbolized := false 674 for _, pc := range cgoPCs { 675 if pc == 0 || n >= max { 676 break 677 } 678 if pcbuf != nil { 679 (*[1 << 20]uintptr)(unsafe.Pointer(pcbuf))[n] = pc 680 } 681 if printing { 682 if cgoSymbolizer == nil { 683 print("non-Go function at pc=", hex(pc), "\n") 684 } else { 685 c := printOneCgoTraceback(pc, max-n, &arg) 686 n += c - 1 // +1 a few lines down 687 anySymbolized = true 688 } 689 } 690 n++ 691 } 692 if anySymbolized { 693 arg.pc = 0 694 callCgoSymbolizer(&arg) 695 } 696 return n 697 } 698 699 func printcreatedby(gp *g) { 700 // Show what created goroutine, except main goroutine (goid 1). 701 pc := gp.gopc 702 f := findfunc(pc) 703 if f.valid() && showframe(f, gp, false, funcID_normal, funcID_normal) && gp.goid != 1 { 704 printcreatedby1(f, pc) 705 } 706 } 707 708 func printcreatedby1(f funcInfo, pc uintptr) { 709 print("created by ", funcname(f), "\n") 710 tracepc := pc // back up to CALL instruction for funcline. 711 if pc > f.entry() { 712 tracepc -= sys.PCQuantum 713 } 714 file, line := funcline(f, tracepc) 715 print("\t", file, ":", line) 716 if pc > f.entry() { 717 print(" +", hex(pc-f.entry())) 718 } 719 print("\n") 720 } 721 722 func traceback(pc, sp, lr uintptr, gp *g) { 723 traceback1(pc, sp, lr, gp, 0) 724 } 725 726 // tracebacktrap is like traceback but expects that the PC and SP were obtained 727 // from a trap, not from gp->sched or gp->syscallpc/gp->syscallsp or getcallerpc/getcallersp. 728 // Because they are from a trap instead of from a saved pair, 729 // the initial PC must not be rewound to the previous instruction. 730 // (All the saved pairs record a PC that is a return address, so we 731 // rewind it into the CALL instruction.) 732 // If gp.m.libcall{g,pc,sp} information is available, it uses that information in preference to 733 // the pc/sp/lr passed in. 734 func tracebacktrap(pc, sp, lr uintptr, gp *g) { 735 if gp.m.libcallsp != 0 { 736 // We're in C code somewhere, traceback from the saved position. 737 traceback1(gp.m.libcallpc, gp.m.libcallsp, 0, gp.m.libcallg.ptr(), 0) 738 return 739 } 740 traceback1(pc, sp, lr, gp, _TraceTrap) 741 } 742 743 func traceback1(pc, sp, lr uintptr, gp *g, flags uint) { 744 // If the goroutine is in cgo, and we have a cgo traceback, print that. 745 if iscgo && gp.m != nil && gp.m.ncgo > 0 && gp.syscallsp != 0 && gp.m.cgoCallers != nil && gp.m.cgoCallers[0] != 0 { 746 // Lock cgoCallers so that a signal handler won't 747 // change it, copy the array, reset it, unlock it. 748 // We are locked to the thread and are not running 749 // concurrently with a signal handler. 750 // We just have to stop a signal handler from interrupting 751 // in the middle of our copy. 752 gp.m.cgoCallersUse.Store(1) 753 cgoCallers := *gp.m.cgoCallers 754 gp.m.cgoCallers[0] = 0 755 gp.m.cgoCallersUse.Store(0) 756 757 printCgoTraceback(&cgoCallers) 758 } 759 760 if readgstatus(gp)&^_Gscan == _Gsyscall { 761 // Override registers if blocked in system call. 762 pc = gp.syscallpc 763 sp = gp.syscallsp 764 flags &^= _TraceTrap 765 } 766 if gp.m != nil && gp.m.vdsoSP != 0 { 767 // Override registers if running in VDSO. This comes after the 768 // _Gsyscall check to cover VDSO calls after entersyscall. 769 pc = gp.m.vdsoPC 770 sp = gp.m.vdsoSP 771 flags &^= _TraceTrap 772 } 773 774 // Print traceback. By default, omits runtime frames. 775 // If that means we print nothing at all, repeat forcing all frames printed. 776 n := gentraceback(pc, sp, lr, gp, 0, nil, _TracebackMaxFrames, nil, nil, flags) 777 if n == 0 && (flags&_TraceRuntimeFrames) == 0 { 778 n = gentraceback(pc, sp, lr, gp, 0, nil, _TracebackMaxFrames, nil, nil, flags|_TraceRuntimeFrames) 779 } 780 if n == _TracebackMaxFrames { 781 print("...additional frames elided...\n") 782 } 783 printcreatedby(gp) 784 785 if gp.ancestors == nil { 786 return 787 } 788 for _, ancestor := range *gp.ancestors { 789 printAncestorTraceback(ancestor) 790 } 791 } 792 793 // printAncestorTraceback prints the traceback of the given ancestor. 794 // TODO: Unify this with gentraceback and CallersFrames. 795 func printAncestorTraceback(ancestor ancestorInfo) { 796 print("[originating from goroutine ", ancestor.goid, "]:\n") 797 for fidx, pc := range ancestor.pcs { 798 f := findfunc(pc) // f previously validated 799 if showfuncinfo(f, fidx == 0, funcID_normal, funcID_normal) { 800 printAncestorTracebackFuncInfo(f, pc) 801 } 802 } 803 if len(ancestor.pcs) == _TracebackMaxFrames { 804 print("...additional frames elided...\n") 805 } 806 // Show what created goroutine, except main goroutine (goid 1). 807 f := findfunc(ancestor.gopc) 808 if f.valid() && showfuncinfo(f, false, funcID_normal, funcID_normal) && ancestor.goid != 1 { 809 printcreatedby1(f, ancestor.gopc) 810 } 811 } 812 813 // printAncestorTracebackFuncInfo prints the given function info at a given pc 814 // within an ancestor traceback. The precision of this info is reduced 815 // due to only have access to the pcs at the time of the caller 816 // goroutine being created. 817 func printAncestorTracebackFuncInfo(f funcInfo, pc uintptr) { 818 name := funcname(f) 819 if inldata := funcdata(f, _FUNCDATA_InlTree); inldata != nil { 820 inltree := (*[1 << 20]inlinedCall)(inldata) 821 ix := pcdatavalue(f, _PCDATA_InlTreeIndex, pc, nil) 822 if ix >= 0 { 823 name = funcnameFromNameOff(f, inltree[ix].nameOff) 824 } 825 } 826 file, line := funcline(f, pc) 827 if name == "runtime.gopanic" { 828 name = "panic" 829 } 830 print(name, "(...)\n") 831 print("\t", file, ":", line) 832 if pc > f.entry() { 833 print(" +", hex(pc-f.entry())) 834 } 835 print("\n") 836 } 837 838 func callers(skip int, pcbuf []uintptr) int { 839 sp := getcallersp() 840 pc := getcallerpc() 841 gp := getg() 842 var n int 843 systemstack(func() { 844 n = gentraceback(pc, sp, 0, gp, skip, &pcbuf[0], len(pcbuf), nil, nil, 0) 845 }) 846 return n 847 } 848 849 func gcallers(gp *g, skip int, pcbuf []uintptr) int { 850 return gentraceback(^uintptr(0), ^uintptr(0), 0, gp, skip, &pcbuf[0], len(pcbuf), nil, nil, 0) 851 } 852 853 // showframe reports whether the frame with the given characteristics should 854 // be printed during a traceback. 855 func showframe(f funcInfo, gp *g, firstFrame bool, funcID, childID funcID) bool { 856 mp := getg().m 857 if mp.throwing >= throwTypeRuntime && gp != nil && (gp == mp.curg || gp == mp.caughtsig.ptr()) { 858 return true 859 } 860 return showfuncinfo(f, firstFrame, funcID, childID) 861 } 862 863 // showfuncinfo reports whether a function with the given characteristics should 864 // be printed during a traceback. 865 func showfuncinfo(f funcInfo, firstFrame bool, funcID, childID funcID) bool { 866 // Note that f may be a synthesized funcInfo for an inlined 867 // function, in which case only nameOff and funcID are set. 868 869 level, _, _ := gotraceback() 870 if level > 1 { 871 // Show all frames. 872 return true 873 } 874 875 if !f.valid() { 876 return false 877 } 878 879 if funcID == funcID_wrapper && elideWrapperCalling(childID) { 880 return false 881 } 882 883 name := funcname(f) 884 885 // Special case: always show runtime.gopanic frame 886 // in the middle of a stack trace, so that we can 887 // see the boundary between ordinary code and 888 // panic-induced deferred code. 889 // See golang.org/issue/5832. 890 if name == "runtime.gopanic" && !firstFrame { 891 return true 892 } 893 894 return bytealg.IndexByteString(name, '.') >= 0 && (!hasPrefix(name, "runtime.") || isExportedRuntime(name)) 895 } 896 897 // isExportedRuntime reports whether name is an exported runtime function. 898 // It is only for runtime functions, so ASCII A-Z is fine. 899 func isExportedRuntime(name string) bool { 900 const n = len("runtime.") 901 return len(name) > n && name[:n] == "runtime." && 'A' <= name[n] && name[n] <= 'Z' 902 } 903 904 // elideWrapperCalling reports whether a wrapper function that called 905 // function id should be elided from stack traces. 906 func elideWrapperCalling(id funcID) bool { 907 // If the wrapper called a panic function instead of the 908 // wrapped function, we want to include it in stacks. 909 return !(id == funcID_gopanic || id == funcID_sigpanic || id == funcID_panicwrap) 910 } 911 912 var gStatusStrings = [...]string{ 913 _Gidle: "idle", 914 _Grunnable: "runnable", 915 _Grunning: "running", 916 _Gsyscall: "syscall", 917 _Gwaiting: "waiting", 918 _Gdead: "dead", 919 _Gcopystack: "copystack", 920 _Gpreempted: "preempted", 921 } 922 923 func goroutineheader(gp *g) { 924 gpstatus := readgstatus(gp) 925 926 isScan := gpstatus&_Gscan != 0 927 gpstatus &^= _Gscan // drop the scan bit 928 929 // Basic string status 930 var status string 931 if 0 <= gpstatus && gpstatus < uint32(len(gStatusStrings)) { 932 status = gStatusStrings[gpstatus] 933 } else { 934 status = "???" 935 } 936 937 // Override. 938 if gpstatus == _Gwaiting && gp.waitreason != waitReasonZero { 939 status = gp.waitreason.String() 940 } 941 942 // approx time the G is blocked, in minutes 943 var waitfor int64 944 if (gpstatus == _Gwaiting || gpstatus == _Gsyscall) && gp.waitsince != 0 { 945 waitfor = (nanotime() - gp.waitsince) / 60e9 946 } 947 print("goroutine ", gp.goid, " [", status) 948 if isScan { 949 print(" (scan)") 950 } 951 if waitfor >= 1 { 952 print(", ", waitfor, " minutes") 953 } 954 if gp.lockedm != 0 { 955 print(", locked to thread") 956 } 957 print("]:\n") 958 } 959 960 func tracebackothers(me *g) { 961 level, _, _ := gotraceback() 962 963 // Show the current goroutine first, if we haven't already. 964 curgp := getg().m.curg 965 if curgp != nil && curgp != me { 966 print("\n") 967 goroutineheader(curgp) 968 traceback(^uintptr(0), ^uintptr(0), 0, curgp) 969 } 970 971 // We can't call locking forEachG here because this may be during fatal 972 // throw/panic, where locking could be out-of-order or a direct 973 // deadlock. 974 // 975 // Instead, use forEachGRace, which requires no locking. We don't lock 976 // against concurrent creation of new Gs, but even with allglock we may 977 // miss Gs created after this loop. 978 forEachGRace(func(gp *g) { 979 if gp == me || gp == curgp || readgstatus(gp) == _Gdead || isSystemGoroutine(gp, false) && level < 2 { 980 return 981 } 982 print("\n") 983 goroutineheader(gp) 984 // Note: gp.m == getg().m occurs when tracebackothers is called 985 // from a signal handler initiated during a systemstack call. 986 // The original G is still in the running state, and we want to 987 // print its stack. 988 if gp.m != getg().m && readgstatus(gp)&^_Gscan == _Grunning { 989 print("\tgoroutine running on other thread; stack unavailable\n") 990 printcreatedby(gp) 991 } else { 992 traceback(^uintptr(0), ^uintptr(0), 0, gp) 993 } 994 }) 995 } 996 997 // tracebackHexdump hexdumps part of stk around frame.sp and frame.fp 998 // for debugging purposes. If the address bad is included in the 999 // hexdumped range, it will mark it as well. 1000 func tracebackHexdump(stk stack, frame *stkframe, bad uintptr) { 1001 const expand = 32 * goarch.PtrSize 1002 const maxExpand = 256 * goarch.PtrSize 1003 // Start around frame.sp. 1004 lo, hi := frame.sp, frame.sp 1005 // Expand to include frame.fp. 1006 if frame.fp != 0 && frame.fp < lo { 1007 lo = frame.fp 1008 } 1009 if frame.fp != 0 && frame.fp > hi { 1010 hi = frame.fp 1011 } 1012 // Expand a bit more. 1013 lo, hi = lo-expand, hi+expand 1014 // But don't go too far from frame.sp. 1015 if lo < frame.sp-maxExpand { 1016 lo = frame.sp - maxExpand 1017 } 1018 if hi > frame.sp+maxExpand { 1019 hi = frame.sp + maxExpand 1020 } 1021 // And don't go outside the stack bounds. 1022 if lo < stk.lo { 1023 lo = stk.lo 1024 } 1025 if hi > stk.hi { 1026 hi = stk.hi 1027 } 1028 1029 // Print the hex dump. 1030 print("stack: frame={sp:", hex(frame.sp), ", fp:", hex(frame.fp), "} stack=[", hex(stk.lo), ",", hex(stk.hi), ")\n") 1031 hexdumpWords(lo, hi, func(p uintptr) byte { 1032 switch p { 1033 case frame.fp: 1034 return '>' 1035 case frame.sp: 1036 return '<' 1037 case bad: 1038 return '!' 1039 } 1040 return 0 1041 }) 1042 } 1043 1044 // isSystemGoroutine reports whether the goroutine g must be omitted 1045 // in stack dumps and deadlock detector. This is any goroutine that 1046 // starts at a runtime.* entry point, except for runtime.main, 1047 // runtime.handleAsyncEvent (wasm only) and sometimes runtime.runfinq. 1048 // 1049 // If fixed is true, any goroutine that can vary between user and 1050 // system (that is, the finalizer goroutine) is considered a user 1051 // goroutine. 1052 func isSystemGoroutine(gp *g, fixed bool) bool { 1053 // Keep this in sync with internal/trace.IsSystemGoroutine. 1054 f := findfunc(gp.startpc) 1055 if !f.valid() { 1056 return false 1057 } 1058 if f.funcID == funcID_runtime_main || f.funcID == funcID_handleAsyncEvent { 1059 return false 1060 } 1061 if f.funcID == funcID_runfinq { 1062 // We include the finalizer goroutine if it's calling 1063 // back into user code. 1064 if fixed { 1065 // This goroutine can vary. In fixed mode, 1066 // always consider it a user goroutine. 1067 return false 1068 } 1069 return fingStatus.Load()&fingRunningFinalizer == 0 1070 } 1071 return hasPrefix(funcname(f), "runtime.") 1072 } 1073 1074 // SetCgoTraceback records three C functions to use to gather 1075 // traceback information from C code and to convert that traceback 1076 // information into symbolic information. These are used when printing 1077 // stack traces for a program that uses cgo. 1078 // 1079 // The traceback and context functions may be called from a signal 1080 // handler, and must therefore use only async-signal safe functions. 1081 // The symbolizer function may be called while the program is 1082 // crashing, and so must be cautious about using memory. None of the 1083 // functions may call back into Go. 1084 // 1085 // The context function will be called with a single argument, a 1086 // pointer to a struct: 1087 // 1088 // struct { 1089 // Context uintptr 1090 // } 1091 // 1092 // In C syntax, this struct will be 1093 // 1094 // struct { 1095 // uintptr_t Context; 1096 // }; 1097 // 1098 // If the Context field is 0, the context function is being called to 1099 // record the current traceback context. It should record in the 1100 // Context field whatever information is needed about the current 1101 // point of execution to later produce a stack trace, probably the 1102 // stack pointer and PC. In this case the context function will be 1103 // called from C code. 1104 // 1105 // If the Context field is not 0, then it is a value returned by a 1106 // previous call to the context function. This case is called when the 1107 // context is no longer needed; that is, when the Go code is returning 1108 // to its C code caller. This permits the context function to release 1109 // any associated resources. 1110 // 1111 // While it would be correct for the context function to record a 1112 // complete a stack trace whenever it is called, and simply copy that 1113 // out in the traceback function, in a typical program the context 1114 // function will be called many times without ever recording a 1115 // traceback for that context. Recording a complete stack trace in a 1116 // call to the context function is likely to be inefficient. 1117 // 1118 // The traceback function will be called with a single argument, a 1119 // pointer to a struct: 1120 // 1121 // struct { 1122 // Context uintptr 1123 // SigContext uintptr 1124 // Buf *uintptr 1125 // Max uintptr 1126 // } 1127 // 1128 // In C syntax, this struct will be 1129 // 1130 // struct { 1131 // uintptr_t Context; 1132 // uintptr_t SigContext; 1133 // uintptr_t* Buf; 1134 // uintptr_t Max; 1135 // }; 1136 // 1137 // The Context field will be zero to gather a traceback from the 1138 // current program execution point. In this case, the traceback 1139 // function will be called from C code. 1140 // 1141 // Otherwise Context will be a value previously returned by a call to 1142 // the context function. The traceback function should gather a stack 1143 // trace from that saved point in the program execution. The traceback 1144 // function may be called from an execution thread other than the one 1145 // that recorded the context, but only when the context is known to be 1146 // valid and unchanging. The traceback function may also be called 1147 // deeper in the call stack on the same thread that recorded the 1148 // context. The traceback function may be called multiple times with 1149 // the same Context value; it will usually be appropriate to cache the 1150 // result, if possible, the first time this is called for a specific 1151 // context value. 1152 // 1153 // If the traceback function is called from a signal handler on a Unix 1154 // system, SigContext will be the signal context argument passed to 1155 // the signal handler (a C ucontext_t* cast to uintptr_t). This may be 1156 // used to start tracing at the point where the signal occurred. If 1157 // the traceback function is not called from a signal handler, 1158 // SigContext will be zero. 1159 // 1160 // Buf is where the traceback information should be stored. It should 1161 // be PC values, such that Buf[0] is the PC of the caller, Buf[1] is 1162 // the PC of that function's caller, and so on. Max is the maximum 1163 // number of entries to store. The function should store a zero to 1164 // indicate the top of the stack, or that the caller is on a different 1165 // stack, presumably a Go stack. 1166 // 1167 // Unlike runtime.Callers, the PC values returned should, when passed 1168 // to the symbolizer function, return the file/line of the call 1169 // instruction. No additional subtraction is required or appropriate. 1170 // 1171 // On all platforms, the traceback function is invoked when a call from 1172 // Go to C to Go requests a stack trace. On linux/amd64, linux/ppc64le, 1173 // linux/arm64, and freebsd/amd64, the traceback function is also invoked 1174 // when a signal is received by a thread that is executing a cgo call. 1175 // The traceback function should not make assumptions about when it is 1176 // called, as future versions of Go may make additional calls. 1177 // 1178 // The symbolizer function will be called with a single argument, a 1179 // pointer to a struct: 1180 // 1181 // struct { 1182 // PC uintptr // program counter to fetch information for 1183 // File *byte // file name (NUL terminated) 1184 // Lineno uintptr // line number 1185 // Func *byte // function name (NUL terminated) 1186 // Entry uintptr // function entry point 1187 // More uintptr // set non-zero if more info for this PC 1188 // Data uintptr // unused by runtime, available for function 1189 // } 1190 // 1191 // In C syntax, this struct will be 1192 // 1193 // struct { 1194 // uintptr_t PC; 1195 // char* File; 1196 // uintptr_t Lineno; 1197 // char* Func; 1198 // uintptr_t Entry; 1199 // uintptr_t More; 1200 // uintptr_t Data; 1201 // }; 1202 // 1203 // The PC field will be a value returned by a call to the traceback 1204 // function. 1205 // 1206 // The first time the function is called for a particular traceback, 1207 // all the fields except PC will be 0. The function should fill in the 1208 // other fields if possible, setting them to 0/nil if the information 1209 // is not available. The Data field may be used to store any useful 1210 // information across calls. The More field should be set to non-zero 1211 // if there is more information for this PC, zero otherwise. If More 1212 // is set non-zero, the function will be called again with the same 1213 // PC, and may return different information (this is intended for use 1214 // with inlined functions). If More is zero, the function will be 1215 // called with the next PC value in the traceback. When the traceback 1216 // is complete, the function will be called once more with PC set to 1217 // zero; this may be used to free any information. Each call will 1218 // leave the fields of the struct set to the same values they had upon 1219 // return, except for the PC field when the More field is zero. The 1220 // function must not keep a copy of the struct pointer between calls. 1221 // 1222 // When calling SetCgoTraceback, the version argument is the version 1223 // number of the structs that the functions expect to receive. 1224 // Currently this must be zero. 1225 // 1226 // The symbolizer function may be nil, in which case the results of 1227 // the traceback function will be displayed as numbers. If the 1228 // traceback function is nil, the symbolizer function will never be 1229 // called. The context function may be nil, in which case the 1230 // traceback function will only be called with the context field set 1231 // to zero. If the context function is nil, then calls from Go to C 1232 // to Go will not show a traceback for the C portion of the call stack. 1233 // 1234 // SetCgoTraceback should be called only once, ideally from an init function. 1235 func SetCgoTraceback(version int, traceback, context, symbolizer unsafe.Pointer) { 1236 if version != 0 { 1237 panic("unsupported version") 1238 } 1239 1240 if cgoTraceback != nil && cgoTraceback != traceback || 1241 cgoContext != nil && cgoContext != context || 1242 cgoSymbolizer != nil && cgoSymbolizer != symbolizer { 1243 panic("call SetCgoTraceback only once") 1244 } 1245 1246 cgoTraceback = traceback 1247 cgoContext = context 1248 cgoSymbolizer = symbolizer 1249 1250 // The context function is called when a C function calls a Go 1251 // function. As such it is only called by C code in runtime/cgo. 1252 if _cgo_set_context_function != nil { 1253 cgocall(_cgo_set_context_function, context) 1254 } 1255 } 1256 1257 var cgoTraceback unsafe.Pointer 1258 var cgoContext unsafe.Pointer 1259 var cgoSymbolizer unsafe.Pointer 1260 1261 // cgoTracebackArg is the type passed to cgoTraceback. 1262 type cgoTracebackArg struct { 1263 context uintptr 1264 sigContext uintptr 1265 buf *uintptr 1266 max uintptr 1267 } 1268 1269 // cgoContextArg is the type passed to the context function. 1270 type cgoContextArg struct { 1271 context uintptr 1272 } 1273 1274 // cgoSymbolizerArg is the type passed to cgoSymbolizer. 1275 type cgoSymbolizerArg struct { 1276 pc uintptr 1277 file *byte 1278 lineno uintptr 1279 funcName *byte 1280 entry uintptr 1281 more uintptr 1282 data uintptr 1283 } 1284 1285 // printCgoTraceback prints a traceback of callers. 1286 func printCgoTraceback(callers *cgoCallers) { 1287 if cgoSymbolizer == nil { 1288 for _, c := range callers { 1289 if c == 0 { 1290 break 1291 } 1292 print("non-Go function at pc=", hex(c), "\n") 1293 } 1294 return 1295 } 1296 1297 var arg cgoSymbolizerArg 1298 for _, c := range callers { 1299 if c == 0 { 1300 break 1301 } 1302 printOneCgoTraceback(c, 0x7fffffff, &arg) 1303 } 1304 arg.pc = 0 1305 callCgoSymbolizer(&arg) 1306 } 1307 1308 // printOneCgoTraceback prints the traceback of a single cgo caller. 1309 // This can print more than one line because of inlining. 1310 // Returns the number of frames printed. 1311 func printOneCgoTraceback(pc uintptr, max int, arg *cgoSymbolizerArg) int { 1312 c := 0 1313 arg.pc = pc 1314 for c <= max { 1315 callCgoSymbolizer(arg) 1316 if arg.funcName != nil { 1317 // Note that we don't print any argument 1318 // information here, not even parentheses. 1319 // The symbolizer must add that if appropriate. 1320 println(gostringnocopy(arg.funcName)) 1321 } else { 1322 println("non-Go function") 1323 } 1324 print("\t") 1325 if arg.file != nil { 1326 print(gostringnocopy(arg.file), ":", arg.lineno, " ") 1327 } 1328 print("pc=", hex(pc), "\n") 1329 c++ 1330 if arg.more == 0 { 1331 break 1332 } 1333 } 1334 return c 1335 } 1336 1337 // callCgoSymbolizer calls the cgoSymbolizer function. 1338 func callCgoSymbolizer(arg *cgoSymbolizerArg) { 1339 call := cgocall 1340 if panicking.Load() > 0 || getg().m.curg != getg() { 1341 // We do not want to call into the scheduler when panicking 1342 // or when on the system stack. 1343 call = asmcgocall 1344 } 1345 if msanenabled { 1346 msanwrite(unsafe.Pointer(arg), unsafe.Sizeof(cgoSymbolizerArg{})) 1347 } 1348 if asanenabled { 1349 asanwrite(unsafe.Pointer(arg), unsafe.Sizeof(cgoSymbolizerArg{})) 1350 } 1351 call(cgoSymbolizer, noescape(unsafe.Pointer(arg))) 1352 } 1353 1354 // cgoContextPCs gets the PC values from a cgo traceback. 1355 func cgoContextPCs(ctxt uintptr, buf []uintptr) { 1356 if cgoTraceback == nil { 1357 return 1358 } 1359 call := cgocall 1360 if panicking.Load() > 0 || getg().m.curg != getg() { 1361 // We do not want to call into the scheduler when panicking 1362 // or when on the system stack. 1363 call = asmcgocall 1364 } 1365 arg := cgoTracebackArg{ 1366 context: ctxt, 1367 buf: (*uintptr)(noescape(unsafe.Pointer(&buf[0]))), 1368 max: uintptr(len(buf)), 1369 } 1370 if msanenabled { 1371 msanwrite(unsafe.Pointer(&arg), unsafe.Sizeof(arg)) 1372 } 1373 if asanenabled { 1374 asanwrite(unsafe.Pointer(&arg), unsafe.Sizeof(arg)) 1375 } 1376 call(cgoTraceback, noescape(unsafe.Pointer(&arg))) 1377 } 1378