c++ - malloc_consolidate 中的 SIGABRT - __FUNCTION__ 是否有可能返回 NULL？

Question

我正在使用以下代码在 ARM 上登录:

template <typename T>
MyClass& operator<<(T const& t)
{
    try
    {
        m_buffer << t;
    }
    catch (...)
    {
        /* No exceptions */
    }
    return *this;
}

这样使用:

myClass <<__FUNCTION__<< " some string and int" << 5;

但是有一次，我遇到了这样的崩溃(来自数千次测试)。 __FUNCTION__ 是否有可能返回 NULL(在本例中函数名长度为 20)？

Program terminated with signal 6, Aborted.
    #0  0x3695f46c in *__GI_raise (sig=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:67
67  ../nptl/sysdeps/unix/sysv/linux/raise.c: No such file or directory.
    in ../nptl/sysdeps/unix/sysv/linux/raise.c
(gdb) bt full
    #0  0x3695f46c in *__GI_raise (sig=6) at   ../nptl/sysdeps/unix/sysv/linux/raise.c:67
        pid = <value optimized out>
        selftid = 1673
        res = <value optimized out>
    #1  0x36964d70 in *__GI_abort () at abort.c:92
        act = {__sigaction_handler = {sa_handler = 0, sa_sigaction = 0}, sa_mask = {__val = {0 <repeats 32 times>}}, sa_flags = 0, sa_restorer = 0}
        sigs = {__val = {32, 0 <repeats 31 times>}}
    #2  0x369a3e4c in __malloc_assert (assertion=<value optimized out>, file=0x36a5f560 "malloc.c", line=<value optimized out>, function=<value optimized out>) at malloc.c:352
    No locals.
    #3  0x369a41c0 in malloc_consolidate (av=0x34781de0) at malloc.c:5345
        fb = <value optimized out>
        maxfb = 0x36a79288
        p = 0x728818
        nextp = 0x6ddec8
        unsorted_bin = 0x36a7928c
        first_unsorted = <value optimized out>
        nextchunk = 0x728ac8
        size = 688
        nextsize = 880297072
        prevsize = <value optimized out>
        bck = <value optimized out>
        fwd = 0xbec
        __func__ = "malloc_consolidate"
    #4  0x369a70d8 in _int_malloc (av=0x36a7925c, bytes=<value optimized out>) at malloc.c:4573
        nb = <value optimized out>
        idx = 1673
        bin = <value optimized out>
        victim = 0x36a78000
        size = <value optimized out>
        victim_index = <value optimized out>
        remainder = <value optimized out>
        remainder_size = <value optimized out>
        block = <value optimized out>
        bit = <value optimized out>
        map = <value optimized out>
        fwd = <value optimized out>
        bck = <value optimized out>
        errstr = <value optimized out>
        __func__ = "_int_malloc"
    #5  0x369a83d4 in _do_malloc (bytes=525) at malloc.c:4011
            ar_ptr = 0x36a7925c
            victim = <value optimized out>
            __func__ = "_do_malloc"
    #6  0x369aa0e8 in *__GI___libc_malloc (bytes=525) at malloc.c:3648
            mem = <value optimized out>
    #7  0x350b1f4c in operator new(unsigned int) () from /lib/libstdc++.so.6
    No symbol table info available.
    #8  0x3508f0e8 in std::string::_Rep::_S_create(unsigned int, unsigned int, std::allocator<char> const&) () from /lib/libstdc++.so.6
    No symbol table info available.
    #9  0x3508fa4c in std::string::_Rep::_M_clone(std::allocator<char> const&, unsigned int) () from /lib/libstdc++.so.6
    No symbol table info available.
    #10 0x350905d0 in std::string::reserve(unsigned int) () from /lib/libstdc++.so.6
    No symbol table info available.
    #11 0x35089de4 in std::basic_stringbuf<char, std::char_traits<char>, std::allocator<char> >::overflow(int) () from /lib/libstdc++.so.6
    No symbol table info available.
    #12 0x3508e648 in std::basic_streambuf<char, std::char_traits<char> >::xsputn(char const*, int) () from /lib/libstdc++.so.6
    No symbol table info available.
    #13 0x35087604 in std::basic_ostream<char, std::char_traits<char> >& std::__ostream_insert<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*, int) () from /lib/libstdc++.so.6
    No symbol table info available.
    #14 0x35087958 in std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*) () from /lib/libstdc++.so.6
    No symbol table info available.
    #15 0x350e8974 in MyClass::operator<< <char [21]> (this=0x34782200, t=...) at ...

使用 valgrind 我看不到任何奇怪的东西。

LE:在中止期间打印以下消息:malloc.c:5345: malloc_consolidate: Assertion 'p->fd_nextsize->bk_nextsize == p' failed

Answer 1

GCC 文档明确指出 __FUNCTION__ 为您提供了您所在函数的朴素名称。唯一失败的方法是您不在函数中。

很可能你在其他地方有 UB，但正如现在流行的那样，你没有提供 MCVE因此，不可能有信心进一步帮助您。