ptr demangle failed?

Yu Luming
Sun Jan 6 08:54:00 GMT 2013

Hi there,

I got a problem in testing glibc git tree.

For some unknown reason, after installing self-build glibc with some
*unrelated* changes, I got many 

Program received signal SIGSEGV, Segmentation fault.
0x0000000000005770 in ?? ()

I debugged the problem a bit, Noticed it's ptr demangle related
The obvious invalid pointer 0x000000570 came from PTR_DEMANGLE.

I'd like to know if anyone has tips to debug __libc_pthread_init when
it's invoked to do PTR_MANGLE? Or someone could please let me know what
I should check to what could have gone wrong in the initialization of




Starting program: /usr/libexec/ck-get-x11-display-device
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/".

Breakpoint 1, pthread_mutex_lock (mutex=0x607258) at forward.c:192
192     forward.c: No such file or directory.
        in forward.c
(gdb) disassemble
Dump of assembler code for function pthread_mutex_lock:
=> 0x00007ffff7b245c0 <+0>:     mov    0x2b748a(%rip),%eax        #
0x7ffff7ddba50 <__libc_pthread_functions_init>
   0x00007ffff7b245c6 <+6>:     test   %eax,%eax
   0x00007ffff7b245c8 <+8>:     jne    0x7ffff7b245d0
   0x00007ffff7b245ca <+10>:    xor    %eax,%eax
   0x00007ffff7b245cc <+12>:    retq
   0x00007ffff7b245cd <+13>:    nopl   (%rax)
   0x00007ffff7b245d0 <+16>:    mov    0x2b73d1(%rip),%rax        #
0x7ffff7ddb9a8 <__libc_pthread_functions+264>
   0x00007ffff7b245d7 <+23>:    ror    $0x11,%rax
   0x00007ffff7b245db <+27>:    xor    %fs:0x30,%rax
   0x00007ffff7b245e4 <+36>:    jmpq   *%rax
End of assembler dump.
(gdb) p __libc_pthread_functions_init
$1 = 1

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