gdb output

GNU gdb (Debian 7.7.1+dfsg-5) 7.7.1
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Reading symbols from ./busybox_unstripped...done.
(gdb) run wget http://skarnet.org/
Starting program: /home/ska/tmp/busybox/compile/busybox_unstripped wget http://skarnet.org/
Connecting to skarnet.org ([2001:4b98:dc0:41:216:3eff:fe4f:d7aa]:80)

Program received signal SIGSEGV, Segmentation fault.
__fflush_unlocked (f=f@entry=0x0) at src/stdio/fflush.c:6
6               if (f->wpos > f->wbase) {
(gdb) bt
#0  __fflush_unlocked (f=f@entry=0x0) at src/stdio/fflush.c:6
#1  0x0000000000405dfc in fflush_all () at libbb/xfuncs_printf.c:298
#2  0x0000000000405966 in bb_verror_msg (s=s@entry=0x4914f5 "can't open '%s'", p=p@entry=0x7fffffffe638, strerr=0x4889da <errmsg+154> "File exists") at libbb/verror_msg.c:91
#3  0x0000000000405762 in bb_perror_msg_and_die (s=s@entry=0x4914f5 "can't open '%s'") at libbb/perror_msg.c:27
#4  0x0000000000405c26 in xopen3 (pathname=0x6a3120 "index.html", flags=<optimized out>, mode=mode@entry=438) at libbb/xfuncs_printf.c:137
#5  0x0000000000405c32 in xopen (pathname=<optimized out>, flags=<optimized out>) at libbb/xfuncs_printf.c:145
#6  0x000000000041954a in download_one_url (url=<optimized out>) at networking/wget.c:1257
#7  wget_main (argc=<optimized out>, argv=<optimized out>) at networking/wget.c:1398
#8  0x0000000000404ded in run_applet_no_and_exit (applet_no=198, argv=argv@entry=0x7fffffffe900) at libbb/appletlib.c:880
#9  0x0000000000404f7f in run_applet_and_exit (name=0x7fffffffeba0 "wget", argv=argv@entry=0x7fffffffe900) at libbb/appletlib.c:897
#10 0x0000000000404f65 in busybox_main (argv=0x7fffffffe900) at libbb/appletlib.c:840
#11 run_applet_and_exit (name=0x7fffffffeb8d "busybox_unstripped", argv=argv@entry=0x7fffffffe8f8) at libbb/appletlib.c:890
#12 0x0000000000404fec in main (argc=<optimized out>, argv=0x7fffffffe8f8) at libbb/appletlib.c:977
(gdb) i reg
rax            0x7fffffffe5ca   140737488348618
rbx            0x6      6
rcx            0x7fffffffe5a0   140737488348576
rdx            0x0      0
rsi            0x499e87 4824711
rdi            0x0      0
rbp            0x2b     0x2b
rsp            0x7fffffffe560   0x7fffffffe560
r8             0x8080808080808080       -9187201950435737472
r9             0xfefefefefefefeff       -72340172838076673
r10            0xfefefefefefefeff       -72340172838076673
r11            0x0      0
r12            0x1      1
r13            0xb      11
r14            0x4914f5 4789493
r15            0x4889da 4753882
rip            0x47b9b8 0x47b9b8 <__fflush_unlocked+1>
eflags         0x10246  [ PF ZF IF RF ]
cs             0x33     51
ss             0x2b     43
ds             0x0      0
es             0x0      0
fs             0x63     99
gs             0x0      0
(gdb) i proc map
process 997149
Mapped address spaces:

          Start Addr           End Addr       Size     Offset objfile
            0x400000           0x4a0000    0xa0000        0x0 /home/ska/tmp/busybox/compile/busybox_unstripped
            0x69f000           0x6a0000     0x1000    0x9f000 /home/ska/tmp/busybox/compile/busybox_unstripped
            0x6a0000           0x6a4000     0x4000        0x0 [heap]
      0x2aaaaaaab000     0x2aaaaaaad000     0x2000        0x0 [vdso]
      0x2aaaaaaad000     0x2aaaaaaaf000     0x2000        0x0 [vvar]
      0x7ffffffde000     0x7ffffffff000    0x21000        0x0 [stack]
  0xffffffffff600000 0xffffffffff601000     0x1000        0x0 [vsyscall]
(gdb) disas $rip-20,+40
Dump of assembler code from 0x47b9a4 to 0x47b9cc:
   0x000000000047b9a4 <ferror+31>:      add    %eax,0x480874c0(%rbp)
   0x000000000047b9aa <ferror+37>:      mov    %ebp,%edi
   0x000000000047b9ac <ferror+39>:      callq  0x48398f <__unlockfile>
   0x000000000047b9b1 <ferror+44>:      mov    %ebx,%eax
   0x000000000047b9b3 <ferror+46>:      pop    %rdx
   0x000000000047b9b4 <ferror+47>:      pop    %rbx
   0x000000000047b9b5 <ferror+48>:      pop    %rbp
   0x000000000047b9b6 <ferror+49>:      retq
   0x000000000047b9b7 <__fflush_unlocked+0>:    push   %rbx
=> 0x000000000047b9b8 <__fflush_unlocked+1>:    mov    0x38(%rdi),%rax
   0x000000000047b9bc <__fflush_unlocked+5>:    mov    %rdi,%rbx
   0x000000000047b9bf <__fflush_unlocked+8>:    cmp    %rax,0x28(%rdi)
   0x000000000047b9c3 <__fflush_unlocked+12>:   ja     0x47b9e2 <__fflush_unlocked+43>
   0x000000000047b9c5 <__fflush_unlocked+14>:   mov    0x8(%rbx),%rsi
   0x000000000047b9c9 <__fflush_unlocked+18>:   mov    0x10(%rbx),%rax
End of assembler dump.