首先，我想为无法缩小问题范围而无法分享重现该错误的简短程序而表示歉意。
外部库 (FUSE) 调用 strncpy “随机”覆盖 shared_ptr<mutex>在我的代码中，当我尝试锁定该互斥体时，这会导致段错误。我用 valgrind 运行我的程序，它没有捕获任何内存错误(下面的 valgrind 标志)。当我在 gdb 中运行代码并在 shared_ptr 上设置一个观察点时，它在调用 strncpy 时中断。 gdb 表示所有 strncpy的参数(dest、src 和 nbytes)已被“优化”，这让我认为它在该调用中使用了未初始化的内存。我的解释正确吗？知道原因是什么吗？
这是指针被覆盖时 gdb 的堆栈跟踪:
#0 __strncpy_ssse3 () at ../sysdeps/x86_64/multiarch/strcpy-ssse3.S:2482
#1 0x0000003245809094 in strncpy (__len=<optimized out>, __src=<optimized out>, __dest=<optimized out>) at /usr/include/bits/string3.h:120
#2 add_name (buf=<optimized out>, bufsize=<optimized out>, s=<optimized out>, name=<optimized out>) at fuse.c:907
#3 0x000000324580997c in try_get_path (f=<optimized out>, nodeid=<optimized out>, name=<optimized out>, path=<optimized out>, wnodep=<optimized out>, need_lock=<optimized out>) at fuse.c:956
#4 0x000000324580a281 in get_path_common (f=<optimized out>, nodeid=<optimized out>, name=<optimized out>, path=<optimized out>, wnode=<optimized out>) at fuse.c:1152
#5 0x0000003245812432 in fuse_lib_unlink (req=<optimized out>, parent=<optimized out>, name=<optimized out>) at fuse.c:1198
#6 0x0000003245817057 in fuse_ll_process_buf (data=0x6f5650, buf=0x7fffffffd850, ch=<optimized out>) at fuse_lowlevel.c:2441
#7 0x000000324581388f in fuse_session_loop (se=0x6f8410) at fuse_loop.c:40
#8 0x000000324580b698 in fuse_loop (f=<optimized out>) at fuse.c:4309
#9 0x000000324581bb8f in fuse_main_common (argc=<optimized out>, argv=<optimized out>, op=<optimized out>, op_size=<optimized out>, user_data=<optimized out>, compat=<optimized out>) at helper.c:355
#10 0x000000000046f1b6 in main (argc=4, argv=0x7fffffffdec8) at ../src/fuse.cpp:100
这是我运行 valgrind 的参数:
valgrind --tool=memcheck --leak-check=yes --show-reachable=yes --num-callers=20 --track-fds=yes
最佳答案
此错误是由于使用 new 创建 shared_ptr，然后将其类型转换为 weak_ptr 并删除它造成的。
关于C++ strncpy 参数 "optimized out"；覆盖随机内存，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/16027993/