tor uses full cpu when unplugged
Hi. Here goes another stupid report of mine. I'm sorry:
When I unplug my network cord, tor starts using my full cpu. If I run service tor stop, it loops and never kills it. I have to kill it with a SIGPWR. I don't know if it's related, but I use wicd.
How do I debug this to provide useful information? If we can prevent disclosing my OS, that would be nice.
Trac:
Username: zqcxobbe
Activity
changed milestone to %Tor: unspecified
added 034-deferred-20180602 034-triage-20180328 035-removed-20180711 component::core tor/tor cpu hang milestone::Tor: unspecified owner::ahf parent::25500 priority::high reporter::zqcxobbe resolution::worksforme resource-management severity::normal sponsor8-maybe sponsor::8-can status::closed tor tor-client type::defect labels
Replying to zqcxobbe:
Hi. Here goes another stupid report of mine. I'm sorry:
When I unplug my network cord,
torstarts using my full cpu. If I runservice tor stop, it loops and never kills it. I have to kill it with aSIGPWR. I don't know if it's related, but I use wicd.How do I debug this to provide useful information? If we can prevent disclosing my OS, that would be nice.
I forgot to say that I am using torsocks with another application when this happens. I built torsocks by myself in this way: https://trac.torproject.org/projects/tor/ticket/8398#comment:9
Trac:
Username: zqcxobbe-
I managed to solve it, and I cannot reproduce anymore. What I did was to install torsocks from official repositories, and re-install it with my own version. The problem is gone, and I cannot make it happen again. I tried to remove the official version before reinstalling, but that did not bring back the problem. I don't know what happened.
Trac:
Username: zqcxobbe -
Replying to zqcxobbe:
I managed to solve it, and I cannot reproduce anymore. What I did was to install torsocks from official repositories, and re-install it with my own version. The problem is gone, and I cannot make it happen again. I tried to remove the official version before reinstalling, but that did not bring back the problem. I don't know what happened.
It's still there. How it happened: suspended the computer, unplugged network and power cords, started the computer (came back from suspension) without power cord (laptop), worked a little on unrelated stuff (no torsocks running) and after a couple of minutes, tor started using up to 98% of the CPU.
Trac:
Username: zqcxobbe
Status: closed to reopened
Resolution: fixed to N/A What tor version? (what configure options used?) What libevent version?
How do I debug this to provide useful information?
[ticket:4588#comment:1 To debug], it would be good to know where we're actually freezing. Try running with "DisableDebuggerAttachment 0", then if it locks up again, attach a debugger with "gdb -p {PID of tor}", and use "bt" to get a stack trace and figure out where Tor is stalled?
Trac:
Keywords: tor cpu deleted, tor cpu hang added-
Replying to cypherpunks:
What tor version? (what configure options used?) What libevent version?
Tor version 0.2.7.6 (git-605ae665009853bd). 2.0.21-stable-1ubuntu1 libevent-2.0-5_2.0.21-stable-1ubuntu1_amd64.deb
However, and I'm really sorry, I haven't been able to reproduce this. I swear by all that is free that this happened to me at least three times. If it happens again, I will use your instructions and report. Double apologies if this was a duplicate. I did search for something similar (freezing is not really what happened; it started to again as soon as I plugged back the cord).
Thank you again for my getting my privacy back.
Trac:
Username: zqcxobbe -
Replying to cypherpunks:
[ticket:4588#comment:1 To debug], it would be good to know where we're actually freezing. Try running with "DisableDebuggerAttachment 0", then if it locks up again, attach a debugger with "gdb -p {PID of tor}", and use "bt" to get a stack trace and figure out where Tor is stalled?
It happened again. I tried the suggestion above, but I only got "No stack" in gdb. Any ideas of how to get some useful information?
Trac:
Username: zqcxobbe -
Replying to cypherpunks:
"Could not attach to process." and/or "ptrace: Operation not permitted." too? I don't remember any of that, but I'll check when it happens again.
Trac:
Username: zqcxobbe -
Replying to zqcxobbe:
Replying to cypherpunks:
"Could not attach to process." and/or "ptrace: Operation not permitted." too? I don't remember any of that, but I'll check when it happens again.
I hope that this helps
$ sudo gdb -p 2369 GNU gdb (Ubuntu 7.7.1-0ubuntu5~14.04.2) 7.7.1 Copyright (C) 2014 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> 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-linux-gnu". Type "show configuration" for configuration details. For bug reporting instructions, please see: <http://www.gnu.org/software/gdb/bugs/>. Find the GDB manual and other documentation resources online at: <http://www.gnu.org/software/gdb/documentation/>. For help, type "help". Type "apropos word" to search for commands related to "word". Attaching to process 2369 Reading symbols from /usr/bin/tor...(no debugging symbols found)...done. Reading symbols from /lib/x86_64-linux-gnu/libz.so.1...(no debugging symbols found)...done. Loaded symbols for /lib/x86_64-linux-gnu/libz.so.1 Reading symbols from /lib/x86_64-linux-gnu/libm.so.6...Reading symbols from /usr/lib/debug//lib/x86_64-linux-gnu/libm-2.19.so...done. done. Loaded symbols for /lib/x86_64-linux-gnu/libm.so.6 Reading symbols from /usr/lib/x86_64-linux-gnu/libevent-2.0.so.5...(no debugging symbols found)...done. Loaded symbols for /usr/lib/x86_64-linux-gnu/libevent-2.0.so.5 Reading symbols from /lib/x86_64-linux-gnu/libssl.so.1.0.0...(no debugging symbols found)...done. Loaded symbols for /lib/x86_64-linux-gnu/libssl.so.1.0.0 Reading symbols from /lib/x86_64-linux-gnu/libcrypto.so.1.0.0...(no debugging symbols found)...done. Loaded symbols for /lib/x86_64-linux-gnu/libcrypto.so.1.0.0 Reading symbols from /usr/lib/x86_64-linux-gnu/libseccomp.so.2...(no debugging symbols found)...done. Loaded symbols for /usr/lib/x86_64-linux-gnu/libseccomp.so.2 Reading symbols from /lib/x86_64-linux-gnu/libpthread.so.0...Reading symbols from /usr/lib/debug//lib/x86_64-linux-gnu/libpthread-2.19.so...done. done. [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1". Loaded symbols for /lib/x86_64-linux-gnu/libpthread.so.0 Reading symbols from /lib/x86_64-linux-gnu/libc.so.6...Reading symbols from /usr/lib/debug//lib/x86_64-linux-gnu/libc-2.19.so...done. done. Loaded symbols for /lib/x86_64-linux-gnu/libc.so.6 Reading symbols from /lib/x86_64-linux-gnu/libdl.so.2...Reading symbols from /usr/lib/debug//lib/x86_64-linux-gnu/libdl-2.19.so...done. done. Loaded symbols for /lib/x86_64-linux-gnu/libdl.so.2 Reading symbols from /lib64/ld-linux-x86-64.so.2...Reading symbols from /usr/lib/debug//lib/x86_64-linux-gnu/ld-2.19.so...done. done. Loaded symbols for /lib64/ld-linux-x86-64.so.2 Reading symbols from /lib/x86_64-linux-gnu/libgcc_s.so.1...(no debugging symbols found)...done. Loaded symbols for /lib/x86_64-linux-gnu/libgcc_s.so.1 Reading symbols from /lib/x86_64-linux-gnu/libnss_compat.so.2...Reading symbols from /usr/lib/debug//lib/x86_64-linux-gnu/libnss_compat-2.19.so...done. done. Loaded symbols for /lib/x86_64-linux-gnu/libnss_compat.so.2 Reading symbols from /lib/x86_64-linux-gnu/libnsl.so.1...Reading symbols from /usr/lib/debug//lib/x86_64-linux-gnu/libnsl-2.19.so...done. done. Loaded symbols for /lib/x86_64-linux-gnu/libnsl.so.1 Reading symbols from /lib/x86_64-linux-gnu/libnss_nis.so.2...Reading symbols from /usr/lib/debug//lib/x86_64-linux-gnu/libnss_nis-2.19.so...done. done. Loaded symbols for /lib/x86_64-linux-gnu/libnss_nis.so.2 Reading symbols from /lib/x86_64-linux-gnu/libnss_files.so.2...Reading symbols from /usr/lib/debug//lib/x86_64-linux-gnu/libnss_files-2.19.so...done. done. Loaded symbols for /lib/x86_64-linux-gnu/libnss_files.so.2 0x000056505b2d65b0 in circuit_get_global_list () (gdb) bt #0 0x000056505b2d65b0 in circuit_get_global_list () #1 0x000056505b2e27fa in circuit_stream_is_being_handled () #2 0x000056505b2d0878 in ?? () #3 0x000056505b2d429c in circuit_establish_circuit () #4 0x000056505b2e5051 in circuit_launch_by_extend_info () #5 0x000056505b2e5b75 in ?? () #6 0x000056505b2e6422 in connection_ap_handshake_attach_circuit () #7 0x000056505b306cf8 in connection_ap_handshake_rewrite_and_attach () #8 0x000056505b336d3f in ?? () #9 0x00007feed8b0efd3 in ?? () from /usr/lib/x86_64-linux-gnu/libevent-2.0.so.5 #10 0x00007feed8b0f0a9 in ?? () from /usr/lib/x86_64-linux-gnu/libevent-2.0.so.5 #11 0x00007feed8af2f24 in event_base_loop () from /usr/lib/x86_64-linux-gnu/libevent-2.0.so.5 #12 0x000056505b25e49d in do_main_loop () #13 0x000056505b2625ad in tor_main () #14 0x000056505b25b7e9 in main ()Trac:
Username: zqcxobbe 
See also #25461 (moved) and #24857 (moved) for other profiling / cpu load tickets. Should we merge them, or pick our favorite and close the others?
Trac:
Parent: N/A to #25500 (moved)mentioned in issue #24857 (moved)
mentioned in issue #25461 (moved)
moved to tpo/core/tor#18614 (closed)
