Fix PR kern/185813 "SOCK_SEQPACKET AF_UNIX sockets with asymmetrical

buffers drop packets".  It was caused by a check for the space available
in a sockbuf, but it was checking the wrong sockbuf.

sys/sys/sockbuf.h
sys/kern/uipc_sockbuf.c
    Add sbappendaddr_nospacecheck_locked(), which is just like
    sbappendaddr_locked but doesn't validate the receiving socket's
    space.  Factor out common code into sbappendaddr_locked_internal().
    We shouldn't simply make sbappendaddr_locked check the space and
    then call sbappendaddr_nospacecheck_locked, because that would cause
    the O(n) function m_length to be called twice.

sys/kern/uipc_usrreq.c
    Use sbappendaddr_nospacecheck_locked for SOCK_SEQPACKET sockets,
    because the receiving sockbuf's size limit is irrelevant.

tests/sys/kern/unix_seqpacket_test.c
    Now that 185813 is fixed, pipe_128k_8k fails intermittently due to
    185812.  Make it fail every time by adding a usleep after starting
    the writer thread and before starting the reader thread in
    test_pipe.  That gives the writer time to fill up its send buffer.
    Also, clear the expected failure message due to 185813.  It actually
    said "185812", but that was a typo.

PR:		kern/185813
Reviewed by:	silence from freebsd-net@ and rwatson@
MFC after:	3 weeks
Sponsored by:	Spectra Logic Corporation

1 files changed, 6 insertions, 1 deletions

diff --git a/tests/sys/kern/unix_seqpacket_test.c b/tests/sys/kern/unix_seqpacket_test.c
index f2904ae..51769c4 100644
--- a/tests/sys/kern/unix_seqpacket_test.c
+++ b/tests/sys/kern/unix_seqpacket_test.c
@@ -361,6 +361,12 @@ test_pipe(size_t sndbufsize, size_t rcvbufsize)
 	reader_data.so = sv[1];
 	ATF_REQUIRE_EQ(0, pthread_create(&writer, NULL, test_pipe_writer,
 	    				 (void*)&writer_data));
+	/* 
+	 * Give the writer time to start writing, and hopefully block, before
+	 * starting the reader.  This increases the likelihood of the test case
+	 * failing due to PR kern/185812
+	 */
+	usleep(1000);
 	ATF_REQUIRE_EQ(0, pthread_create(&reader, NULL, test_pipe_reader,
 	    				 (void*)&reader_data));
 
@@ -951,7 +957,6 @@ ATF_TC_BODY(pipe_simulator_8k_128k, tc)
 ATF_TC_WITHOUT_HEAD(pipe_simulator_128k_8k);
 ATF_TC_BODY(pipe_simulator_128k_8k, tc)
 {
-	atf_tc_expect_fail("PR kern/185812 SOCK_SEQPACKET AF_UNIX sockets with asymmetrical buffers drop packets");
 	test_pipe_simulator(131072, 8192);
 }