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Re: Crash on running SFTP after openssl upgrade

From: Daniel Stenberg <>
Date: Wed, 1 Aug 2012 23:32:13 +0200 (CEST)

On Wed, 1 Aug 2012, William Tan wrote:

> I am seeing this segmentation fault after upgrading my application server to
> openssl 1.0.1c. The server is paired with libssh2 version 1.2.9 and libcurl
> version 7.21.7. Notice that the session becomes NULL in the highest frame
> and that's why it's crashed at transport.c:824 when dereferencing it. Was
> there any bugs that might cause this crash?

I can't recall any such bug (fixes) since 7.21.7.

But please try out the most recent libcurl first to see if the problem is
still there or not.

> Is there anything I can look to find out who cleaned up the session and when
> it happened?

Sure, write up a test program that can repeat the crash and then use gdb and
step through libcurl and see where and why it does this mistake and what can
be done to prevent it from crashing it.

It could also be an idea to provide such a source code to us so that we can
help out!

It might help to catch the problem earlier if you run the program with

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Received on 2012-08-01