dns.setServers() crash #894

BLeQuerrec · 2015-02-19T16:50:29Z

Hi,

In a Vagrant Ubuntu environment, io.js crashes with this code:

$ cat dns.js
var dns = require('dns');

dns.resolveSoa('example.org', function(err, soa){
    console.log(soa.nsname);
    dns.resolve4(soa.nsname, function (err, nameServers) {
        console.log(dns.getServers());
        dns.setServers(nameServers);
        console.log(dns.getServers());
    });
});

Expected result:

$ iojs dns.js
sns.dns.icann.org
[ '10.0.2.3' ]
[ '199.4.28.26' ]

Actual result:

$ iojs dns.js
sns.dns.icann.org
[ '10.0.2.3' ]
iojs: ../deps/cares/src/ares_destroy.c:102: ares__destroy_servers_state: Assertion `ares__is_list_empty(&server->queries_to_server)' failed.
Aborted (core dumped)

Other informations:

$ cat /etc/os-release
NAME="Ubuntu"
VERSION="14.04.1 LTS, Trusty Tahr"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 14.04.1 LTS"
VERSION_ID="14.04"
HOME_URL="http://www.ubuntu.com/"
SUPPORT_URL="http://help.ubuntu.com/"
BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/"
$ iojs -v
v1.2.0

DNS test (in test/simple/test-dns.js) ends successfully. This bug can be fixed by removing line 102 in deps/cares/src/ares_destroy.c.
Node.js bug: nodejs/node-v0.x-archive#9243

The text was updated successfully, but these errors were encountered:

tellnes · 2015-02-19T17:14:04Z

I'm seeing similar results on os x 10.9.5

$ iojs dns.js
sns.dns.icann.org
[ '10.0.0.1' ]
Assertion failed: (ares__is_list_empty(&server->queries_to_server)), function ares__destroy_servers_state, file ../deps/cares/src/ares_destroy.c, line 102.
Abort trap: 6

rvagg · 2015-02-19T22:57:40Z

@iojs/tc can someone qualified jump on this? otherwise it'll have to go in to "known issues" in 1.3.0.

indutny · 2015-02-19T23:01:59Z

Will do.

`ares_set_servers()` should terminate all active queries to previous servers before destroying them. When invoking query callback remove it from the queue, to ensure that it won't be called two times. Fix: nodejs#894

indutny · 2015-02-20T00:22:22Z

I have two solutions to the problem:

cares: fix set_servers during active queries #899
throw in JS if there is any active queries
wait until query completion before changing the servers

What do you think will be most preferable? cc @bnoordhuis

silverwind · 2015-02-20T00:39:11Z

wait until query completion before changing the servers

Would that block new queries from using the updated servers until all outstanding requests finish? If so, any way to have setServers apply for all following queries?

tellnes · 2015-02-20T01:10:19Z

The best solution would be that queries created before calling setServers is using the old servers while queries created after calling setServers is using the new servers.

If I understand your solutions correctly, that would mean wait until query completion and queue up new queries.

silverwind · 2015-02-20T10:03:30Z

Meant what @tellnes said. If that's possible, there's no need to throw.

indutny · 2015-02-20T10:05:25Z

Good suggestion. I'll see what I can do.

silverwind · 2015-03-10T15:43:43Z

I'm unsure how far you got here @indutny, but if it proves easier to add support for a server option on resolve like I proposed in #1071, we could possibly deprecate setServers and getServers in 2.0 or 3.0.

silverwind · 2015-03-11T16:12:31Z

Once this is fixed to work like #894 (comment) describes, I can work on adding the resolve option for a truly async API. Probably not worth to deprecate after all.

Use an EE with some state data to gate async resolution operations in c-ares so that setServers() can run independently. Likely a temporary fix for nodejs#894 with a better solution being to fix c-ares to do this without barfing.

silverwind · 2016-02-08T16:59:59Z

@emotional-engineering c-ares is now on GitHub. Would you mind posting your patch as a pull request there? @indutny mentioned they should be more responsive now.

silverwind · 2016-02-12T06:04:42Z

Filed c-ares/c-ares#41

jasnell · 2016-04-22T17:14:24Z

Closing this as it's a duplicate of #1071 (or, 1071 is a duplicate of this... either way, we don't need two issues tracking the same problem). It's still an open issue, however.

silverwind · 2016-04-22T17:29:44Z

I have to object. This is the original issue tracking the crash. The other one is more of an API topic.

@indutny you're still assigned here?

jasnell · 2016-04-22T17:44:04Z

@silverwind .. ok, no problem :-) just trying to do a bit of housecleaning.

raimondi1337 · 2016-12-15T00:15:47Z

Ran into this issue today on node v6.9.1

I'm running this loop thousands of times one after another and it works:

    dns.setServers([server['ip']]);
    dns.lookup('something.com', fn()(...));

but this breaks after two executions resulting in the error in the original post:

    dns.setServers([server['ip']]);
    dns.resolve('something.com', fn()(...));

has this been fixed for lookup but not resolve or something like that?

silverwind · 2016-12-15T06:34:39Z

@raimondi1337 lookup uses the system resolver, so does not go through c-ares. setServers has no effect on lookup.

The callback function in cares_query is synchronous and called before closed. So dns.setServers in the synchronous callback before closed will occur crashing. Fixes: nodejs#894 Refs: https://github.com/nodejs/node/blob/v6.9.4/deps/cares/src/ares_process.c#L1332-L1333 Refs: https://github.com/OpenSIPS/opensips/blob/2.3.0/proxy.c PR-URL: nodejs#13050 Reviewed-By: Anna Henningsen <[email protected]>

The callback function in cares_query is synchronous and called before closed. So dns.setServers in the synchronous callback before closed will occur crashing. Fixes: #894 Refs: https://github.com/nodejs/node/blob/v6.9.4/deps/cares/src/ares_process.c#L1332-L1333 Refs: https://github.com/OpenSIPS/opensips/blob/2.3.0/proxy.c Backport-PR-URL: #13724 PR-URL: #13050 Reviewed-By: Anna Henningsen <[email protected]>

dzek69 · 2018-06-16T21:24:05Z

If noone noticed - this is fixed with 9.3.0 version and fix seems to be backported to 8.10.0 too.

But I monkey patched dns module to fix that - if anyone needs to keep unpatched Node version and doesn't want the crashes - please use my fix.
More information here: https://github.com/dzek69/node-dns-bugfix

Original commit message: Prevent changing name servers while queries are outstanding Changing name servers doesn't work, per c-ares/c-ares#41. Better to return an error code than to crash. Refs: c-ares/c-ares#41 Refs: c-ares/c-ares#191 Refs: nodejs#894

The callback function in cares_query is synchronous and called before closed. So dns.setServers in the synchronous callback before closed will occur crashing. Fixes: nodejs/node#894 Refs: https://github.com/nodejs/node/blob/v6.9.4/deps/cares/src/ares_process.c#L1332-L1333 Refs: https://github.com/OpenSIPS/opensips/blob/2.3.0/proxy.c

Fishrock123 added the confirmed-bug Issues with confirmed bugs. label Feb 19, 2015

indutny self-assigned this Feb 19, 2015

indutny mentioned this issue Feb 20, 2015

cares: fix set_servers during active queries #899

Closed

rvagg mentioned this issue Feb 20, 2015

Release proposal: v1.3.0 #872

Closed

BLeQuerrec mentioned this issue Feb 23, 2015

dns.setServers() crash nodejs/node-v0.x-archive#9243

Closed

This was referenced Feb 24, 2015

Release proposal: v1.4.0 #932

Closed

Release proposal: v1.4.2 #995

Closed

Release proposal: v1.4.3 #1017

Closed

This was referenced Mar 3, 2015

Replace deps/cares with pure-javascript alternative #1013

Closed

dns.setServers doesn't play well with async code #1071

Closed

This was referenced Mar 6, 2015

Release proposal: v1.5.0 #1060

Closed

Release proposal: v1.5.1 #1096

Closed

subfuzion mentioned this issue Mar 9, 2015

Evangelism: Weekly Update March 13th nodejs/evangelism#41

Closed

silverwind mentioned this issue Mar 10, 2015

Major version bump #1061

Closed

rvagg mentioned this issue Mar 12, 2015

dns: gate setServers to avoid async cares conflicts #1132

Closed

nrvru mentioned this issue Mar 14, 2015

Еженедельник io.js, 13 марта nodejs/nodejs-ru#103

Merged

rvagg mentioned this issue Mar 19, 2015

Release proposal: v1.6.0 #1157

Closed

MylesBorins mentioned this issue Jan 11, 2016

V5.4.1 propose #4626

Merged

This was referenced Jan 19, 2016

V4.2.5 proposal #4768

Merged

/dev/null #4787

Closed

v4.2.6 proposal #4788

Merged

silverwind mentioned this issue Feb 4, 2016

Feature/update cares to 2bae2d56d7866defcee18455c1f2ecfef6c7663d #5090

Closed

silverwind mentioned this issue Feb 12, 2016

ares_set_servers - Assertion failed: ares__is_list_empty c-ares/c-ares#41

Closed

jasnell closed this as completed Apr 22, 2016

silverwind reopened this Apr 22, 2016

XadillaX mentioned this issue May 16, 2017

dns: fix crash while using dns.setServers after dns.resolve4 #13050

Closed

3 tasks

addaleax closed this as completed in 5a948f6 May 18, 2017

XadillaX mentioned this issue Jun 16, 2017

(v6.x backport) dns: fix crash while using dns.setServers after dns.resolve4 #13724

Closed

3 tasks

dzek69 mentioned this issue Jun 16, 2018

dns: occasionally crashing in resolve4 and setServers #14734

Closed

bnoordhuis mentioned this issue Oct 22, 2018

deps: cherry-pick 078e1dc from upstream c-ares #23815

Closed

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dns.setServers() crash #894

dns.setServers() crash #894

BLeQuerrec commented Feb 19, 2015

tellnes commented Feb 19, 2015

rvagg commented Feb 19, 2015

indutny commented Feb 19, 2015

indutny commented Feb 20, 2015

silverwind commented Feb 20, 2015

tellnes commented Feb 20, 2015

silverwind commented Feb 20, 2015

indutny commented Feb 20, 2015

silverwind commented Mar 10, 2015

silverwind commented Mar 11, 2015

silverwind commented Feb 8, 2016

silverwind commented Feb 12, 2016

jasnell commented Apr 22, 2016

silverwind commented Apr 22, 2016 •

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jasnell commented Apr 22, 2016

raimondi1337 commented Dec 15, 2016

silverwind commented Dec 15, 2016

dzek69 commented Jun 16, 2018

dns.setServers() crash #894

dns.setServers() crash #894

Comments

BLeQuerrec commented Feb 19, 2015

tellnes commented Feb 19, 2015

rvagg commented Feb 19, 2015

indutny commented Feb 19, 2015

indutny commented Feb 20, 2015

silverwind commented Feb 20, 2015

tellnes commented Feb 20, 2015

silverwind commented Feb 20, 2015

indutny commented Feb 20, 2015

silverwind commented Mar 10, 2015

silverwind commented Mar 11, 2015

silverwind commented Feb 8, 2016

silverwind commented Feb 12, 2016

jasnell commented Apr 22, 2016

silverwind commented Apr 22, 2016 • edited Loading

jasnell commented Apr 22, 2016

raimondi1337 commented Dec 15, 2016

silverwind commented Dec 15, 2016

dzek69 commented Jun 16, 2018

silverwind commented Apr 22, 2016 •

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