Subject: [libssh2] #223: errors in multi threads applications

[libssh2] #223: errors in multi threads applications

From: libssh2 Trac <>
Date: Fri, 12 Aug 2011 13:52:17 -0000

#223: errors in multi threads applications
  Reporter: mmichele1974@… | Owner:
      Type: defect | Status: new
  Priority: normal | Milestone: 1.2.9
 Component: SFTP | Version: 1.2.7
  Keywords: sftp curl multithread | Blocks:
Blocked By: |
 I'm using libCURL with libssh2 to make multiple put/get to/from sftp
 In order to make my application thread-safe I added the two callbacks:
 in order to lock common data user to crypt/decrypt.
 Unfortunately I take the following segfault:

 (gdb) where
 #0 0x0000000000000000 in ?? ()
 #1 0x0000003980c1bd33 in _libssh2_cipher_crypt (ctx=<value optimized
 out>, algo=<value optimized out>, encrypt=<value optimized out>,
 block=0x7fe45c01f450 "")
     at openssl.c:197
 #2 0x0000003980c18cc9 in _libssh2_transport_write
 (session=0x7fe45c00af10, data=0x7fe45c017f80 "^", data_len=16422) at
 #3 0x0000003980c05c6c in _libssh2_channel_write (channel=0x7fe45c0103f0,
 stream_id=0, buf=0x7fe45c013f50 "", buflen=16413) at channel.c:2014
 #4 0x0000003980c1356a in sftp_write (hnd=0x7fe45c00fdd0,
 buffer=0x7fe45c005989 "", count=<value optimized out>) at sftp.c:1432
 #5 libssh2_sftp_write (hnd=0x7fe45c00fdd0, buffer=0x7fe45c005989 "",
 count=<value optimized out>) at sftp.c:1486
 #6 0x000000398183b4e3 in Curl_sftp_send () from /usr/lib64/
 #7 0x0000003981817a65 in Curl_write () from /usr/lib64/
 #8 0x000000398182b1c7 in Curl_readwrite () from /usr/lib64/
 #9 0x000000398182bca8 in Curl_perform () from /usr/lib64/
 #10 0x00007fe4c30eded3 in acs::curl::Curl::performTransfer
 (this=0x7fe4a4011cc0, isGet=false, fileToTransfer="", targetFilename=
 readData=0x7fe4a4011cc0) at Curl.C:522

 How can I solve this issue?

Ticket URL: <>
libssh2 <>
C library for writing portable SSH2 clients
Received on 2011-08-12