On Wed, Jul 31, 2019 at 10:21:16AM +0200, Martin Liška wrote:
> On 7/31/19 10:08 AM, Jan Hubicka wrote:
> > Hi,
> >
> >> We do not detect jobserver because of Dejagnu is not using it.
> >> And yes, we default to -flto=<numthreads> in LTO tests now. That's
> >> what is causing issues right now.
> >
> > Why the error messages are
> > make[4]: *** write jobserver: Bad file descriptor. Stop.
> > make[4]: *** Waiting for unfinished jobs....
> > make[4]: *** write jobserver: Bad file descriptor. Stop.
> > It seems to me that it is internal make from lto-wrapper trying to get
> > jobserver access?
>
> Hard to guess. Can you Jakub debug that? I don't see the error message.
I can easily reproduce even with
make -j2 -k check-gcc RUNTESTFLAGS=lto.exp=*20081125*
I've added a hack:
--- lto-wrapper.c.jj 2019-07-31 09:46:39.361331843 +0200
+++ lto-wrapper.c 2019-07-31 10:40:57.970302110 +0200
@@ -1430,6 +1430,12 @@ run_gcc (unsigned argc, char *argv[])
jobserver or number of cores. */
auto_parallel = 1;
jobserver = jobserver_active_p ();
+FILE *f = fopen ("/tmp/111x", "a");
+fprintf (f, "%d %s\n", jobserver, getenv ("MAKEFLAGS"));
+fclose (f);
+char buf[1024];
+sprintf (buf, "ls -l /proc/%d/fd >> /tmp/111x", getpid ());
+system (buf);
}
if (linker_output)
and see that in some cases jobserver is 0 and in other cases jobserver is 1.
Examples of both:
0 kw -j2 --jobserver-auth=3,6 --
total 0
lrwx------. 1 jakub jakub 64 Jul 31 10:41 0 -> /dev/pts/4
l-wx------. 1 jakub jakub 64 Jul 31 10:41 1 -> pipe:[75026106]
lr-x------. 1 jakub jakub 64 Jul 31 10:41 10 -> /usr/src/gcc/obj/gcc/libgcc_s.so
lr-x------. 1 jakub jakub 64 Jul 31 10:41 13 -> /usr/lib64/libc.so
lr-x------. 1 jakub jakub 64 Jul 31 10:41 18 -> /usr/src/gcc/obj/gcc/libgcc_s.so
l-wx------. 1 jakub jakub 64 Jul 31 10:41 2 -> /tmp/ccX4y4r3.le
l-wx------. 1 jakub jakub 64 Jul 31 10:41 9 -> pipe:[46167136]
1 kw -j2 --jobserver-auth=3,6 --
total 0
lrwx------. 1 jakub jakub 64 Jul 31 10:41 0 -> /dev/pts/4
l-wx------. 1 jakub jakub 64 Jul 31 10:41 1 -> /tmp/cchSvmBt
lr-x------. 1 jakub jakub 64 Jul 31 10:41 10 -> /usr/lib64/crtn.o
lrwx------. 1 jakub jakub 64 Jul 31 10:41 2 -> /dev/pts/4
lr-x------. 1 jakub jakub 64 Jul 31 10:41 3 -> /usr/lib64/crt1.o
lr-x------. 1 jakub jakub 64 Jul 31 10:41 4 -> /usr/lib64/crti.o
lr-x------. 1 jakub jakub 64 Jul 31 10:41 5 -> /usr/src/gcc/obj/gcc/crtbegin.o
lr-x------. 1 jakub jakub 64 Jul 31 10:41 6 ->
/usr/src/gcc/obj/gcc/testsuite/gcc/c_lto_20081125_0.o
lr-x------. 1 jakub jakub 64 Jul 31 10:41 7 ->
/usr/src/gcc/obj/gcc/testsuite/gcc/c_lto_20081125_1.o
lr-x------. 1 jakub jakub 64 Jul 31 10:41 8 -> /usr/src/gcc/obj/gcc/crtend.o
l-wx------. 1 jakub jakub 64 Jul 31 10:41 9 -> pipe:[46167136]
so, if one is lucky enough and at least one of the two file descriptors in
MAKEFLAGS --jobserver-auth= is closed, it will work fine, but if they are
open, even when they have nothing to do with make, it will fail miserably.
As a partial workaround, I wonder if jobserver_active_p couldn't check (with
fstat/fstat64) if the file descriptors are pipes. It will still not be 100%
reliable, as when you are unlucky the file descriptor could be some
completely unrelated pipe, but at least better than the current state.
Jakub
