transmission-gtk crashed with SIGSEGV in curl_easy_pause()

Status changed to 'Confirmed' because the bug affects multiple users.

Ubuntu 13.10

Transmission crashed twice since i added the download of LibreOffice 4.1.2 from http://tracker.documentfoundation.org:6969/announce.

Fri, 04 Oct 2013 15:59:54 +0400
==============
[Ubuntu]
Description: Ubuntu Saucy Salamander (development branch)
Release: 13.10
[Kernel linux]
Linux vasilisc 3.11.0-11-generic #17-Ubuntu SMP Tue Oct 1 19:42:04 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
[Kernel command line]
BOOT_IMAGE=/boot/vmlinuz-3.11.0-11-generic root=UUID=7e5e7212-570c-4aa9-a3b5-60367081603b ro ipv6.disable=1
transmission-gtk:
  Installed: 2.82-0ubuntu1
  Candidate: 2.82-0ubuntu1
  Version table:
 *** 2.82-0ubuntu1 0
        500 http://archive.ubuntu.com/ubuntu/ saucy/main amd64 Packages
        100 /var/lib/dpkg/status

So, get this crash repeatedly, but not immediately, when I try to download a 700MB video file from archive.org. It's a webseed. The LibreOffice site is not responding as I try to check this, but there's a good chance that torrent has a webseed, too. This crash may be specific to web seeds. (For all I know, that may be all that transmission uses curl for.)

When I restart Transmission, the webseeded torrent downloads again for a while, before crashing. Perhaps it will finish this time. I haven't figured out anything that seems to trigger or precede the crash.

Thanks.

The webseed torrent eventually did finish, after a number of cycles of crashes and restarting. The torrent was complete (and the status was Finished, I believe, FWIW; at any rate it wasn't active) when I removed the torrent from Transmission. That triggered one more instance of this crash. When restarted, Transmission no longer showed the torrent in its list; the deletion from Transmission seems to have finished.

I'm seeing this repeatedly when using webseeds as well:

$ transmission-gtk --version
transmission-gtk 2.82 (14160)

$ gdb transmission-gtk
...
Reading symbols from /usr/bin/transmission-gtk...Reading symbols from /usr/lib/debug/usr/bin/transmission-gtk...done.
(gdb) run
Starting program: /usr/bin/transmission-gtk
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[New Thread 0x7fffea4db700 (LWP 15075)]
[New Thread 0x7fffe9cda700 (LWP 15076)]
[New Thread 0x7fffe3bc9700 (LWP 15077)]
[New Thread 0x7fffe33c8700 (LWP 15078)]
...
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fffc73fe700 (LWP 15086)]
0x00007ffff5a9ac7d in ?? () from /usr/lib/x86_64-linux-gnu/libcurl-gnutls.so.4
(gdb) bt
#0 0x00007ffff5a9ac7d in ?? () from /usr/lib/x86_64-linux-gnu/libcurl-gnutls.so.4
#1 0x00007ffff5ab06a9 in curl_easy_pause () from /usr/lib/x86_64-linux-gnu/libcurl-gnutls.so.4
#2 0x00005555555b9ce2 in tr_webThreadFunc (vsession=0x55555599c400) at web.c:451
#3 0x000055555559cdba in ThreadFunc (_t=0x555555d5bc70) at platform.c:108
#4 0x00007ffff4f79f6e in start_thread (arg=0x7fffc73fe700) at pthread_create.c:311
#5 0x00007ffff4ca49cd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113

I'm also seeing other errors which are possibly related:

Program received signal SIGPIPE, Broken pipe.
[Switching to Thread 0x7fffe33c8700 (LWP 19533)]
0x00007ffff4c9c421 in __libc_writev (fd=<optimized out>, vector=<optimized out>, count=<optimized out>)
    at ../sysdeps/unix/sysv/linux/writev.c:55
55 ../sysdeps/unix/sysv/linux/writev.c: No such file or directory.

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fffc73fe700 (LWP 19808)]
Curl_llist_count (list=list@entry=0xffffffff) at llist.c:158
158 llist.c: No such file or directory.

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fffc73fe700 (LWP 20267)]
Curl_client_write (conn=0x7fffd0d784f0, type=type@entry=892, ptr=ptr@entry=0x7fffd083bc50 "", len=len@entry=16384) at sendf.c:408
408 sendf.c: No such file or directory.

Would you like me to open a new bug report for each of them?

Also seeing this in relation to what seems like web seeds.

Same here, I confirm this is related to web seed.

Got this today on a complete different Notebook (Lenovo L512):

Xubuntu 14.04 32 Bit
Transmission 2.82-1.1ubuntu3

I had added 3 Torrents:
http://torrents.linuxmint.com/announce.php
Linux Mint 17 MATE DVD 32 Bit RC
Linux Mint 17 Cinnamon DVD 32 Bit RC

udp://tracker.publicbt.com:80/announce
udp://tracker.openbittorrent.com:80/announce
Elementary OS stable i386.20130810

I'm also experiencing this exact crash. It happens every time after some minutes of Transmission running, downloading two Linux ISO images (I didn't download anything else on that machine).

Xubuntu 13.10 64 bit 3.11.0-23-generic
Transimission 2.82-0ubuntu1 (14160)

Torrents I'm downloading (2):

Name: elementaryos-stable-i386.20130810.iso
Hash: 455c7898a4f538887c7075e36e800e49f9940653
udp://tracker.publicbt.com:80/announce
udp://tracker.openbittorrent.com:80/announce

Name: lubuntu-14.04-desktop-i386.iso
Hash: ef21436f8b097cb76b7c488dd84f318e3d275a79
http://torrent.ubuntu.com:6969/announce

Stacktrace (entire crash log attached):
 #0 0x00007fd4f87d2c7d in ?? () from /usr/lib/x86_64-linux-gnu/libcurl-gnutls.so.4
 #1 0x00007fd4f87e8689 in curl_easy_pause () from /usr/lib/x86_64-linux-gnu/libcurl-gnutls.so.4
 #2 0x00007fd4fad9cce2 in ?? ()
 #3 0x00007fd4fad7fdba in ?? ()
 #4 0x00007fd4f7cb1f6e in start_thread (arg=0x7fd4c793d700) at pthread_create.c:311
 #5 0x00007fd4f79dc9cd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113

This bug has been fixed upstream, but Ubuntu is still shipping an older version without the fix.

https://trac.transmissionbt.com/ticket/5580

The only change to webseed.c between 2.82 (version in ubuntu) and the version reported as fixed (r14219) is this:

https://trac.transmissionbt.com/changeset/14188/

I have exactly the same issue with Transmission in Ubuntu 14.04.1 LTS. When I download a torrent with web=seeds it crashes and when I download a torrent without a web-seed it works as it should be.

This bug is still present in transmission-gtk 2.84 (14307), and still makes webseeds just about useless. Note that transmission's bug tracker lists #5580 as "closed (worksforme)" and that bug was last updated 2 years ago. This bug should probably be re-raised upstream.