[tor-talk] segfault at 8 ip ... error 4 in tor

Hanspeter Spalinger tor at spahan.ch
Thu Dec 1 15:16:59 UTC 2011

> A newer gdb, or a version of Tor built without PIE turned on, should
> produce a useful stack trace.

I built a new gdb (from the homepage), and got the output below. I too
tried rebuild tor from the source (apt-get source,
dpkg-buildpackage,...) and both times the stack trace looks like this. I
do not understand why gdb does not find the tor-dbg symbols, i installed
them and squeeze gdb finds them, but not the new gdb (i tried the
map-debug configure option and used the -s Option to directly give the
path, but nothing worked)

Does this help? or how should I proceed?


PS: i do not get the crash with debian stable package, i am using the
repository provided by the tor-projct as described in

spahan:~/tor2# ../gdb/gdb-7.3.1/gdb/gdb -s /usr/lib/debug/usr/sbin/tor
tor /var/lib/tor/core
GNU gdb (GDB) 7.3.1
Copyright (C) 2011 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-unknown-linux-gnu".
For bug reporting instructions, please see:
Reading symbols from /usr/sbin/tor...(no debugging symbols found)...done.
[New LWP 28259]
[New LWP 28322]

warning: Can't read pathname for load map: Input/output error.
[Thread debugging using libthread_db enabled]
Core was generated by `/usr/sbin/tor'.
Program terminated with signal 11, Segmentation fault.
#0  0x00007fa968cdfbc3 in ?? ()
(gdb) bt
#0  0x00007fa968cdfbc3 in ?? ()
#1  0x00007fa968cc5e1f in ?? ()
#2  0x00007fa968cc640d in ?? ()
#3  0x00007fa968ca3544 in ?? ()
#4  0x00007fa968c2dac1 in ?? ()
#5  0x00007fa96834f344 in event_base_loop () from /usr/lib/libevent-1.4.so.2
#6  0x00007fa968c2b981 in ?? ()
#7  0x00007fa968c2bc6d in ?? ()
#8  0x00007fa9675efc4d in __libc_start_main () from /lib/libc.so.6
#9  0x00007fa968c2a169 in ?? ()
#10 0x00007ffff0fd4998 in ?? ()
#11 0x000000000000001c in ?? ()
#12 0x0000000000000001 in ?? ()
#13 0x00007ffff0fd5dbc in ?? ()
#14 0x0000000000000000 in ?? ()

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