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Re: libcurl Version 7.66 crashes when uploading a file using https

From: Daniel Stenberg via curl-library <>
Date: Thu, 28 Nov 2019 08:36:27 +0100 (CET)

On Wed, 27 Nov 2019, Arun Jaganath via curl-library wrote:

> While upgrading from libcurl version 7.56.1 to 7.66, I am facing a crash.
> This is while i am trying to upload a file in chunks using https protocol. I
> have set the read callback function using


> I have modified CURL_MAX_WRITE_SIZE from 16384 to 1048608 in order to read
> 1MB. I have recompiled the libcurl Version 7.66 and observed the libcurl
> crash while uploading. Following is the crash dump.

First: it'd be great if you rebuilt your libcurl and kept the debug symbols so
that we could better see exactly where the crash happens, and you could even
run it with gdb and get a full stack trace of it.

Then: does it work if you don't change CURL_MAX_WRITE_SIZE ? You're modifying
libcurl by doing this and I'm afraid we cannot guarantee that this works. It
is not part of the ABI nor the API.

We provide CURLOPT_BUFFERSIZE in the API that can be used to grow the receive
buffer up to 512KB, maybe consider using that instead?

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Received on 2019-11-28