Segfault with ftp get

[johnnypez]

Hi, I'm just trying to do a simple FTP get and hitting a segfault on Ubuntu 14.04.3 LTS with Node 0.10.40 and libcurl 7.35.0.

It works locally on my macbook (osx 10.10.5 / node 0.10.40 / libcurl 7.43.0)

From poking around other segfault issues reported here, it's clear they are very hard to reproduce.

Here's what I use to trigger the error. The ftp host and credentials have been swapped out for dummy credentials.

var Curl, curl;

Curl = require('node-libcurl').Curl;

curl = new Curl;

curl.setOpt(Curl.option.URL, "ftp://dummyuser:dummypass@inbound.acme.com/feed.csv");

curl.setOpt(Curl.option.VERBOSE, 1);

curl.setOpt(Curl.option.DEBUGFUNCTION, require('./debug')); // returns the debug function from node-libcurl examples

curl.on('end', function() {
  return console.log(arguments, curl.getInfo(Curl.info.SIZE_DOWNLOAD));
});

curl.perform();

Which results in a segfault just as the transfer is about to begin.

Hostname was NOT found in DNS cache

  Trying x.x.x.x...

Connected to inbound.acme.com (x.x.x.x) port 21 (#0)

-- RECEIVING HEADER:
220 Acme LLC

-- SENDING HEADER:
USER dummyuser

-- RECEIVING HEADER:
331 Please specify the password.

-- SENDING HEADER:
PASS dummypass

-- RECEIVING HEADER:
230 Login successful.

-- SENDING HEADER:
PWD

-- RECEIVING HEADER:
257 "/"

Entry path is '/'

-- SENDING HEADER:
PASV

Connect data stream passively

ftp_perform ends with SECONDARY: 0

-- RECEIVING HEADER:
227 Entering Passive Mode (x,x,x,x,159,192).

Hostname was NOT found in DNS cache

  Trying x.x.x.x...

Connecting to x.x.x.x (x.x.x.x) port 40000

PID 14645 received SIGSEGV for address: 0x1c81
/home/dev/workspace/myapp/node_modules/segfault-handler/build/Release/segfault-handler.node(+0x1973)[0x7f0a0c176973]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x10340)[0x7f0a15665340]
/usr/lib/x86_64-linux-gnu/libcurl.so.4(+0x3042c)[0x7f0a14e3a42c]
/usr/lib/x86_64-linux-gnu/libcurl.so.4(+0x30cca)[0x7f0a14e3acca]
/usr/lib/x86_64-linux-gnu/libcurl.so.4(+0x335be)[0x7f0a14e3d5be]
/usr/lib/x86_64-linux-gnu/libcurl.so.4(curl_multi_socket_action+0x17)[0x7f0a14e3d627]
/home/dev/workspace/myapp/node_modules/node-libcurl/lib/binding/node_libcurl.node(_ZN11NodeLibcurl5Multi8OnSocketEP9uv_poll_sii+0x4d)[0x7f0a1508755d]
/home/dev/.nvm/v0.10.40/bin/node(uv__io_poll+0x300)[0x9e5a40]
/home/dev/.nvm/v0.10.40/bin/node(uv_run+0xd8)[0x9d9398]
/home/dev/.nvm/v0.10.40/bin/node(_ZN4node5StartEiPPc+0x16c)[0x9853ec]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf5)[0x7f0a152b1ec5]
/home/dev/.nvm/v0.10.40/bin/node(cos+0x129)[0x5a54a9]

So whatever is going wrong is happening in NodeLibcurl::Multi::OnSocket(uv_poll_s*, int, int) I guess but I'm not sure how to debug any further than that.

Any help anyone could offer would be greatly appreciated. Let me know if I need to provide any more information for context.

[JCMais]

Hi,

what version of node-libcurl are you using?

[johnnypez]

Hey, sorry I forgot to add that. It's 0.7.0

[johnnypez]

In case it was anything to do with having an older version of libcurl, I built and installed curl 7.47.1. Then reinstalled node-libcurl 0.7.0 with the --build-from-source flag but still experience the same problem.

[johnnypez]

Just adding more detail as I poke around.
I added libcurl-dbg package and ran my sample code above through gdb.
At this point though, I'm not sure what I'm looking for.

0x00007ffff672e42c in Curl_hash_pick (h=0xf56a20, key=key@entry=0x7fffffffac08, key_len=key_len@entry=4)
    at hash.c:215
215     hash.c: No such file or directory.
(gdb) bt
#0  0x00007ffff672e42c in Curl_hash_pick (h=0xf56a20, key=key@entry=0x7fffffffac08, key_len=key_len@entry=4)
    at hash.c:215
#1  0x00007ffff672ecca in singlesocket (multi=multi@entry=0xf52180, data=data@entry=0xf73990) at multi.c:1953
#2  0x00007ffff67315be in multi_socket (multi=multi@entry=0xf52180, checkall=checkall@entry=false, s=10,
    ev_bitmask=1, running_handles=0xf34714) at multi.c:2235
#3  0x00007ffff6731627 in curl_multi_socket_action (multi_handle=0xf52180, s=<optimized out>,
    ev_bitmask=<optimized out>, running_handles=<optimized out>) at multi.c:2367
#4  0x00007ffff69ad5fb in NodeLibcurl::Multi::OnSocket (handle=0xef6ae8, status=0, events=1)
    at ../src/Multi.cc:187
#5  0x00000000009e5a40 in uv__io_poll (loop=0xeae720 <default_loop_struct>, timeout=-1)
    at ../deps/uv/src/unix/linux-core.c:308
#6  0x00000000009d9398 in uv_run (loop=0xeae720 <default_loop_struct>, mode=<optimized out>)
    at ../deps/uv/src/unix/core.c:317
#7  0x00000000009853ec in node::Start(int, char**) ()
---Type <return> to continue, or q <return> to quit---
#8  0x00007ffff6becec5 in __libc_start_main (main=0x9966a0 <main>, argc=2, argv=0x7fffffffdfe8,
    init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffffffdfd8)
    at libc-start.c:287
#9  0x00000000005a54a9 in _start ()

[JCMais]

Hi, thanks for all the info, I will have time to take a look into it by today or tomorrow.

I didn't tested ftp or ssh with the addon, probably I've forgot to add something. 😄

[johnnypez]

No worries. I actually got it working with libcurl 7.47.1. Even though I had installed that earlier, the lib for 7.35.0 was still around and that was being used when node-libcurl was being installed. I had to add /usr/local/lib to /etc/ld.so.conf to get around it.

[JCMais]

As you got it working after updating libcurl I'm closing this since looks like the issue is from libcurl itself.

If the problem reappears feel free to reopen.