tsan13.go

     1  // Copyright 2023 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 main
     6  
     7  // This program failed when run under the C/C++ ThreadSanitizer.
     8  // There was no TSAN synchronization for the call to the cgo
     9  // traceback routine.
    10  
    11  /*
    12  #cgo CFLAGS: -g -fsanitize=thread
    13  #cgo LDFLAGS: -g -fsanitize=thread
    14  
    15  #include <pthread.h>
    16  #include <stdint.h>
    17  #include <stdlib.h>
    18  #include <sys/time.h>
    19  #include <unistd.h>
    20  
    21  struct tracebackArg {
    22  	uintptr_t  Context;
    23  	uintptr_t  SigContext;
    24  	uintptr_t* Buf;
    25  	uintptr_t  Max;
    26  };
    27  
    28  void tsanTraceback(struct tracebackArg *arg) {
    29  	arg->Buf[0] = 0;
    30  }
    31  
    32  static void* spin(void *arg) {
    33  	size_t n;
    34  	struct timeval tvstart, tvnow;
    35  	int diff;
    36  	void *prev;
    37  	void *cur;
    38  
    39  	prev = NULL;
    40  	gettimeofday(&tvstart, NULL);
    41  	for (n = 0; n < 1<<20; n++) {
    42  		cur = malloc(n);
    43  		free(prev);
    44  		prev = cur;
    45  
    46  		gettimeofday(&tvnow, NULL);
    47  		diff = (tvnow.tv_sec - tvstart.tv_sec) * 1000 * 1000 + (tvnow.tv_usec - tvstart.tv_usec);
    48  
    49  		// Profile frequency is 100Hz so we should definitely
    50  		// get some signals in 50 milliseconds.
    51  		if (diff > 50 * 1000) {
    52  			break;
    53  		}
    54  	}
    55  
    56  	free(prev);
    57  
    58  	return NULL;
    59  }
    60  
    61  static void runThreads(int n) {
    62  	pthread_t ids[64];
    63  	int i;
    64  
    65  	if (n > 64) {
    66  		n = 64;
    67  	}
    68  	for (i = 0; i < n; i++) {
    69  		pthread_create(&ids[i], NULL, spin, NULL);
    70  	}
    71  	for (i = 0; i < n; i++) {
    72  		pthread_join(ids[i], NULL);
    73  	}
    74  }
    75  */
    76  import "C"
    77  
    78  import (
    79  	"io"
    80  	"runtime"
    81  	"runtime/pprof"
    82  	"unsafe"
    83  )
    84  
    85  func main() {
    86  	runtime.SetCgoTraceback(0, unsafe.Pointer(C.tsanTraceback), nil, nil)
    87  	pprof.StartCPUProfile(io.Discard)
    88  	C.runThreads(C.int(runtime.GOMAXPROCS(0)))
    89  	pprof.StopCPUProfile()
    90  }
    91
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