Re: Memory leak with curl_multi_socket_action

On Tue, May 26, 2020 at 2:31 PM James Read <jamesread5737_at_gmail.com> wrote:

>
>
> On Tue, May 26, 2020 at 12:47 PM James Read <jamesread5737_at_gmail.com>
> wrote:
>
>>
>>
>> On Tue, May 26, 2020 at 7:30 AM Patrick Monnerat via curl-library <
>> curl-library_at_cool.haxx.se> wrote:
>>
>>> On 5/26/20 1:15 AM, James Read via curl-library wrote:
>>> >
>>> > git clone https://github.com/JamesRead5737/libcurlmemoryleak.git
>>> >
>>> > No need to make. Just compile with gcc crawler.c -g -lssl -lcurl
>>> > Run valgrind with valgrind -v --tool=memcheck --leak-check=full
>>> > --show-reachable=yes --track-origins=yes --log-file=memcheck.log
>>> ./a.out
>>> >
>>> > This should reproduce what I've been talking about.
>>> >
>>> Upon termination, you call curl_multi_cleanup() that still has easy
>>> handles attached to. As a consequence, they are never freed. See 1st
>>> description paragraph of
>>> https://curl.haxx.se/libcurl/c/curl_multi_cleanup.html.
>>>
>>> Unfortunately, there is no API that lists attached easy handles, so you
>>> have to keep a list externally and unlink+cleanup them explicitly before
>>> curl_multi_cleanup call. I tried that (with a very primitive
>>> single-linked list in ConnInfo) and it works: all memory leaks disappear.
>>>
>>
>> Does the example at https://curl.haxx.se/libcurl/c/ephiperfifo.html have
>> the same problem? The code I'm trying to debug seems to follow that pattern
>> very closely. Do you have any example code that fixes the problem?
>>
>
> I guess on reflection what I really need to do is figure out how I can
> finish off all running connections before exiting when a ctrl c is
> encountered. Would that clear up the memory leaks?
>

OK. I modified the code to exit cleaner and clean up in progress downloads.

git clone https://github.com/JamesRead5737/libcurlmemoryleak.git

This seems to have cleared up some of the memory loss reported in valgrind
but valgrind is still reporting memory leaks. Also consider the following
output from my program:

Parsed sites: 0, 54 parallel connections, 55 still runninggg Exiting
normally.
Parsed sites: 0, 0 parallel connections, 14 still runningg Finished all in
progress downloads.
Exiting.

When parallel connections reaches 0 g->still_running is still reporting a
number of easy handles in progress. How can this be? Surely, the answer to
this question is the answer to the memory leaks?

James Read

>
> James Read
>
>
>>
>> James Read
>>
>>
>>
>>>
>>> Patrick
>>>
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>>
>>

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Received on 2020-05-26