Date: Tue, 24 Sep 2002 10:16:14 -0700 (PDT) From: Nate Lawson <nate@root.org> To: current@freebsd.org Cc: des@freebsd.org Subject: Coredump from pkg_add + analysis Message-ID: <Pine.BSF.4.21.0209231037310.62714-100000@root.org>
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pkg_add coredumps when installing dependencies from remote. This is
really annoying because you have to manually track down dependencies and
install them (say, for a critical package like cvsup). This has been
reported multiple times and is 100% repeatable. It's been broken for a
few months (ever since *conn was added to libfetch).
Anyway, here's the trace and analysis.
(gdb) bt
#0 0x2809d6fe in SSL_write () from /usr/lib/libssl.so.2
#1 0x080564f0 in _fetch_write (conn=0x80940c0, buf=0x8098200 "NOOP",
len=4)
at /usr/src/lib/libfetch/common.c:485
#2 0x080565a7 in _fetch_putln (conn=0x80940c0, str=0x8098200 "NOOP",
len=134840832) at /usr/src/lib/libfetch/common.c:513
#3 0x08054023 in _ftp_cmd (conn=0x80940c0, fmt=0x8098200 "NOOP")
at /usr/src/lib/libfetch/ftp.c:187
#4 0x08055524 in _ftp_cached_connect (url=0x80940c0, purl=0x8098200,
flags=0x8098200 "NOOP") at /usr/src/lib/libfetch/ftp.c:867
#5 0x0805577c in _ftp_request (url=0x8093000, op=0x8059f29 "RETR",
us=0x0,
purl=0x0, flags=0x0) at /usr/src/lib/libfetch/ftp.c:933
#6 0x080558e0 in fetchXGetFTP (url=0x2f363833, us=0x2f363833,
flags=0x8098200 "NOOP") at /usr/src/lib/libfetch/ftp.c:967
#7 0x08050e76 in fetchXGet (URL=0x8093000, us=0x0, flags=0x0)
at /usr/src/lib/libfetch/fetch.c:83
#8 0x080511c8 in fetchXGetURL (URL=0x8098200 "NOOP", us=0x8098200,
flags=0x8098200 "NOOP") at /usr/src/lib/libfetch/fetch.c:180
#9 0x08051200 in fetchGetURL (URL=0x8098200 "NOOP", flags=0x8098200
"NOOP")
at /usr/src/lib/libfetch/fetch.c:192
#10 0x080500c1 in fileGetURL ()
#11 0x0804b53d in pkg_do (
pkg=0x805e880
"ftp://ftp.freebsd.org/pub/FreeBSD/ports/i386/packages-5-current/All/xpdf-1.01.tbz") at
/usr/src/usr.sbin/pkg_install/add/perform.c:297
#12 0x0804aceb in pkg_perform (pkgs=0x8090c80)
at /usr/src/usr.sbin/pkg_install/add/perform.c:50
#13 0x0804aa4f in real_main (argc=-1077937142, argv=0xbfbffb0c)
at /usr/src/usr.sbin/pkg_install/add/main.c:215
#14 0x0804d41e in main (argc=134840832, argv=0xbfbffb00)
at /usr/src/usr.sbin/pkg_install/lib/pkgwrap.c:88
#15 0x0804a5c9 in _start ()
(gdb) fr 1
#1 0x080564f0 in _fetch_write (conn=0x80940c0, buf=0x8098200 "NOOP",
len=4)
at /usr/src/lib/libfetch/common.c:485
485 wlen = SSL_write(conn->ssl, buf, len);
(gdb) list
480 }
481 }
482 errno = 0;
483 #ifdef WITH_SSL
484 if (conn->ssl != NULL)
485 wlen = SSL_write(conn->ssl, buf, len);
486 else
487 #endif
488 wlen = write(conn->sd, buf, len);
489 if (wlen == 0)
(gdb) print conn
$1 = (struct fetchconn *) 0x80940c0
(gdb) print *conn
$2 = {sd = 1651863599, buf = 0x6572462f <Address 0x6572462f out of
bounds>,
bufsize = 1146307173, buflen = 1919905839, err = 1764717428,
ssl = 0x2f363833, ssl_ctx = 0x6b636170, ssl_cert = 0x73656761,
ssl_meth = 0x632d352d, ref = 1701999221}
(gdb) print conn->ssl
$3 = (struct ssl_st *) 0x2f363833
Obviously, the problem is that we're bogusly sending an FTP command to SSL
because conn (and &conn->ssl) was overwritten with garbage. Looking into
it further, the problem appears to be with cached_connection in ftp.c.
Often, the connection is closed (when the reference count goes to 0) but
cached_connection is never set to NULL thus causing it to be reused even
though *conn is invalid.
There's a bit of a layering problem with the ftp/fetch semantics.
_fetch_close() is used to shutdown the connection (and handles reference
counting but the connection caching is done at the ftp layer. Either the
connection cache should be moved to the fetch layer so open/close can deal
with it properly (better) or the ftp layer needs to check for a ref count
of 1 and invalidate the cache before closing it (worse).
A lot of people would really really appreciate it if someone would choose
an approach and fix this.
-Nate
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