Re: error: git-remote-https died of signal 13

From: Jeff King <peff@peff.net>
Date: Apr 24, 2014, 04:15 UTC
Message-ID: <20140424041504.GA17398@sigill.intra.peff.net>
In-Reply-To: <CAEHyFQLPYh2b5CsmadazDJG3paHL7JDY4JhT=xf=wHXhLd=EkQ@mail.gmail.com>

On Wed, Apr 23, 2014 at 07:49:09AM -0400, Greg M wrote:

Show 24 quoted lines

> > The easiest way to find it is probably to attach a debugger to the
> > running git-remote-https, and get a backtrace when it dies from SIGPIPE.
> > You'll probably want to install your system's debug packages for curl,
> > too.
> >
> 
> The backtrace:
> 
> Program received signal SIGPIPE, Broken pipe.
> 0x00007fdcfd511a2d in write () from /usr/lib/libpthread.so.0
> (gdb) bt
> #0  0x00007fdcfd511a2d in write () from /usr/lib/libpthread.so.0
> #1  0x00007fdcfd81a0f6 in sock_write () from /usr/lib/libcrypto.so.1.0.0
> #2  0x00007fdcfd817edb in BIO_write () from /usr/lib/libcrypto.so.1.0.0
> #3  0x00007fdcfc662902 in ssl3_write_pending () from /usr/lib/libssl.so.1.0.0
> #4  0x00007fdcfc664b77 in ssl3_dispatch_alert () from /usr/lib/libssl.so.1.0.0
> #5  0x00007fdcfc660822 in ssl3_shutdown () from /usr/lib/libssl.so.1.0.0
> #6  0x00007fdcfd2e944e in Curl_ossl_close () from /usr/lib/libcurl.so.4
> #7  0x00007fdcfd2b6459 in Curl_disconnect () from /usr/lib/libcurl.so.4
> #8  0x00007fdcfd2c8131 in curl_multi_cleanup () from /usr/lib/libcurl.so.4
> #9  0x000000000040764b in ?? ()
> #10 0x0000000000404e4d in ?? ()
> #11 0x00007fdcfcf0fb05 in __libc_start_main () from /usr/lib/libc.so.6
> #12 0x000000000040552e in ?? ()

Thanks, that's very helpful. I wasn't able to reproduce your problem locally, but I suspect the curl patch below may fix it:

diff --git a/lib/multi.c b/lib/multi.c
index bc93264..72e4825 100644
--- a/lib/multi.c
+++ b/lib/multi.c
@@ -1804,10 +1804,13 @@ static void close_all_connections(struct Curl_multi *multi)
 
   conn = Curl_conncache_find_first_connection(multi->conn_cache);
   while(conn) {
+    SIGPIPE_VARIABLE(pipe_st);
     conn->data = multi->closure_handle;
 
+    sigpipe_ignore(conn->data, &pipe_st);
     /* This will remove the connection from the cache */
     (void)Curl_disconnect(conn, FALSE);
+    sigpipe_restore(&pipe_st);
 
     conn = Curl_conncache_find_first_connection(multi->conn_cache);
   }

Let me know if you need any pointers on getting curl built or tested
with git.

Daniel, I think the similar fix to curl_multi_cleanup in commit a900d45
missed this code path, and we need something like the above patch. I
know you were trying to keep the SIGPIPE mess at the entrance-points to
the library, and this works against that. But we need a SessionHandle to
pass to sigpipe_ignore to look at its "no_signal" flag, and of course in
the case of multi we may have several such handles. If there's a similar
flag we can check on the multi handle, we could just cover all of
curl_multi_cleanup with a single ignore/reset pair.

-Peff