segfault on handshake!

[sbromberger]

Brand new julia REPL:

julia> sess = GnuTLS.Session()
GnuTLS.Session(Ptr{Void} @0x00007fc88402ac00,false,#undef,#undef)

julia> set_credentials!(sess, GnuTLS.CertificateStore())

julia> set_priority_string!(sess)

julia> associate_stream(sess, connect("github.com", 443))

julia> handshake!(sess)

signal (11): Segmentation fault: 11
unknown function (ip: 16777630)
Segmentation fault: 11

[sbromberger]

May also be related to

julia> using GnuTLS

julia> sess = GnuTLS.Session()
GnuTLS.Session(Ptr{Void} @0x00007fdbb2236200,false,#undef,#undef)

julia> set_priority_string!(sess)

julia> set_credentials!(sess, GnuTLS.CertificateStore())

julia> associate_stream(sess, connect("github.com", 443))

julia> handshake!(sess)
ERROR: MemoryError()

[quinnj]

@Keno any ideas on this? It may have something to do with the ccall overhaul since this is 0.4 specific?

[quinnj]

Here's my full backtrack on OSX

julia> GnuTLS.handshake!(stream)

signal (11): Segmentation fault: 11
buffer_or_write at stream.jl:763
write at stream.jl:833
jlcapi_write_43076 at  (unknown line)
_gnutls_writev_emu at /Users/jacobquinn/.julia/v0.4/Homebrew/deps/usr/lib/libgnutls.dylib (unknown line)
_gnutls_io_write_flush at /Users/jacobquinn/.julia/v0.4/Homebrew/deps/usr/lib/libgnutls.dylib (unknown line)
_gnutls_handshake_io_write_flush at /Users/jacobquinn/.julia/v0.4/Homebrew/deps/usr/lib/libgnutls.dylib (unknown line)
_gnutls_send_handshake at /Users/jacobquinn/.julia/v0.4/Homebrew/deps/usr/lib/libgnutls.dylib (unknown line)
send_hello at /Users/jacobquinn/.julia/v0.4/Homebrew/deps/usr/lib/libgnutls.dylib (unknown line)
gnutls_handshake at /Users/jacobquinn/.julia/v0.4/Homebrew/deps/usr/lib/libgnutls.dylib (unknown line)
handshake! at /Users/jacobquinn/.julia/v0.4/GnuTLS/src/GnuTLS.jl:316
jlcall_handshake!_43077 at  (unknown line)
jl_apply at /Users/jacobquinn/julia/src/gf.c:1693
jl_apply at /Users/jacobquinn/julia/src/interpreter.c:53
eval at /Users/jacobquinn/julia/src/interpreter.c:214
jl_toplevel_eval_flex at /Users/jacobquinn/julia/src/toplevel.c:503
jl_eh_restore_state at /Users/jacobquinn/julia/src/./julia.h:1296
eval_user_input at REPL.jl:60
jlcall_eval_user_input_42593 at  (unknown line)
jl_apply at /Users/jacobquinn/julia/src/./julia.h:1108
anonymous at task.jl:89
jl_apply at /Users/jacobquinn/julia/src/task.c:233
Segmentation fault: 11
jq-mbp:julia jacobquinn$ 

[quinnj]

Actually, not sure if my git blame is off here, but I think this commit may be where this started. Any thoughts @amitmurthy?

[amitmurthy]

After changing lines https://github.com/JuliaWeb/GnuTLS.jl/blob/master/src/GnuTLS.jl#L319-L320 to

    old_ptr = pointer(priority)
    ret = ccall((:gnutls_priority_set_direct,gnutls),Int32,(Ptr{Void},Ptr{Uint8},Ptr{Ptr{Uint8}}),s.handle,priority,x)

I can see the same problem on the latest master.

It is segfaulting at https://github.com/JuliaLang/julia/blob/master/base/stream.jl#L756, which is basically isnull(s.sendbuf)

Looking into it, but right now I have no clue as to what could be causing this. Seems like some memory corruption has happened before the handshake! call.

[amitmurthy]

Also https://github.com/JuliaLang/julia/pull/10232 was merged 25 days ago, while this issue has been reported 28 days ago. So, the underlying cause is definitely not https://github.com/JuliaLang/julia/pull/10232, but could be something a few days earlier.

[amitmurthy]

What I have got so far:

I printed the object_ids of the TCPSocket in both GnuTLS.jl in associate_stream

        println("0. $(object_id(s.read))")
        println("0. $(object_id(s.write))")

and in the cfunction generated callback in buffer_or_write in stream.jl via typeof(s) == TCPSocket && println("2. $(object_id(s))")

The object_ids are different.

They should be the same.

[amitmurthy]

I think I found the cause of the segfault. The handle being passed in associate_stream is of the GnuTLS session, while the function in stream.jl expects an AsyncStream.

I think I know how it can be fixed.

[amitmurthy]

Closed by #40