On GNU/Hurd, 'time_units_per_microsec' is zero

[civodul]

Hello,

On GNU/Hurd, time_units_per_microsec is zero, leading to SIGFPE early on when running a Fibers 1.3.1 program:

Core was generated by `/gnu/store/mljlxj4gc8rii7891sza3vda7y06fyf8-guile-3.0.9/bin/guile --no-auto-comp'.
Program terminated with signal SIGFPE, Arithmetic exception.

warning: Unexpected size of section `.reg2/130' in core file.
#0  0x025f7b9d in __udivmoddi4 (rp=0x0, d=0, n=0) at ../../../gcc-11.3.0/libgcc/libgcc2.c:1026
1026    ../../../gcc-11.3.0/libgcc/libgcc2.c: No such file or directory.
[Current thread is 1 (process 130)]
(gdb) bt
#0  0x025f7b9d in __udivmoddi4 (rp=0x0, d=0, n=0) at ../../../gcc-11.3.0/libgcc/libgcc2.c:1026
#1  __udivdi3 (n=0, d=0) at ../../../gcc-11.3.0/libgcc/libgcc2.c:1300
#2  0x025f73e6 in run_event_loop (p=0x103e724) at extensions/libevent.c:218
#3  0x025f7523 in scm_primitive_event_loop (lst=0x37e2768, wakefd=0x42, wokefd=0x3e, timeout=0x2) at extensions/libevent.c:270
#4  0x0108e451 in ?? () from /gnu/store/mljlxj4gc8rii7891sza3vda7y06fyf8-guile-3.0.9/lib/libguile-3.0.so.1
#5  0x010f9785 in ?? () from /gnu/store/mljlxj4gc8rii7891sza3vda7y06fyf8-guile-3.0.9/lib/libguile-3.0.so.1
#6  0x01108536 in scm_call_n () from /gnu/store/mljlxj4gc8rii7891sza3vda7y06fyf8-guile-3.0.9/lib/libguile-3.0.so.1
#7  0x01079e0b in scm_primitive_eval () from /gnu/store/mljlxj4gc8rii7891sza3vda7y06fyf8-guile-3.0.9/lib/libguile-3.0.so.1
#8  0x010a5064 in scm_primitive_load () from /gnu/store/mljlxj4gc8rii7891sza3vda7y06fyf8-guile-3.0.9/lib/libguile-3.0.so.1
#9  0x0108e410 in ?? () from /gnu/store/mljlxj4gc8rii7891sza3vda7y06fyf8-guile-3.0.9/lib/libguile-3.0.so.1
#10 0x010f9785 in ?? () from /gnu/store/mljlxj4gc8rii7891sza3vda7y06fyf8-guile-3.0.9/lib/libguile-3.0.so.1
#11 0x01108536 in scm_call_n () from /gnu/store/mljlxj4gc8rii7891sza3vda7y06fyf8-guile-3.0.9/lib/libguile-3.0.so.1
#12 0x01079e0b in scm_primitive_eval () from /gnu/store/mljlxj4gc8rii7891sza3vda7y06fyf8-guile-3.0.9/lib/libguile-3.0.so.1
#13 0x0107fcc3 in scm_eval () from /gnu/store/mljlxj4gc8rii7891sza3vda7y06fyf8-guile-3.0.9/lib/libguile-3.0.so.1
#14 0x010d7a33 in scm_shell () from /gnu/store/mljlxj4gc8rii7891sza3vda7y06fyf8-guile-3.0.9/lib/libguile-3.0.so.1
#15 0x0109108d in ?? () from /gnu/store/mljlxj4gc8rii7891sza3vda7y06fyf8-guile-3.0.9/lib/libguile-3.0.so.1
#16 0x0107804e in ?? () from /gnu/store/mljlxj4gc8rii7891sza3vda7y06fyf8-guile-3.0.9/lib/libguile-3.0.so.1
#17 0x0108e410 in ?? () from /gnu/store/mljlxj4gc8rii7891sza3vda7y06fyf8-guile-3.0.9/lib/libguile-3.0.so.1
#18 0x010f9785 in ?? () from /gnu/store/mljlxj4gc8rii7891sza3vda7y06fyf8-guile-3.0.9/lib/libguile-3.0.so.1
#19 0x01108536 in scm_call_n () from /gnu/store/mljlxj4gc8rii7891sza3vda7y06fyf8-guile-3.0.9/lib/libguile-3.0.so.1
#20 0x01079a60 in scm_call_2 () from /gnu/store/mljlxj4gc8rii7891sza3vda7y06fyf8-guile-3.0.9/lib/libguile-3.0.so.1
#21 0x010f4d4b in ?? () from /gnu/store/mljlxj4gc8rii7891sza3vda7y06fyf8-guile-3.0.9/lib/libguile-3.0.so.1
#22 0x011270c3 in ?? () from /gnu/store/mljlxj4gc8rii7891sza3vda7y06fyf8-guile-3.0.9/lib/libguile-3.0.so.1
#23 0x010efa9b in scm_c_catch () from /gnu/store/mljlxj4gc8rii7891sza3vda7y06fyf8-guile-3.0.9/lib/libguile-3.0.so.1
#24 0x0107a7cd in scm_c_with_continuation_barrier () from /gnu/store/mljlxj4gc8rii7891sza3vda7y06fyf8-guile-3.0.9/lib/libguile-3.0.so.1
#25 0x010f4a1b in ?? () from /gnu/store/mljlxj4gc8rii7891sza3vda7y06fyf8-guile-3.0.9/lib/libguile-3.0.so.1
#26 0x011b4fb4 in GC_call_with_stack_base () from /gnu/store/qqgp6fd8xq55dc4gknvgk6d8wjvxxgn3-libgc-8.2.2/lib/libgc.so.1
#27 0x010ef94a in scm_with_guile () from /gnu/store/mljlxj4gc8rii7891sza3vda7y06fyf8-guile-3.0.9/lib/libguile-3.0.so.1
#28 0x01098840 in scm_boot_guile () from /gnu/store/mljlxj4gc8rii7891sza3vda7y06fyf8-guile-3.0.9/lib/libguile-3.0.so.1
#29 0x0804911a in ?? ()
#30 0x0156e290 in __libc_start_call_main (argv=0x103ede4, argc=8, main=0x80490c0) at ../sysdeps/generic/libc_start_call_main.h:23
#31 __libc_start_main_impl (main=0x80490c0, argc=8, argv=0x103ede4, init=0x0, fini=0x0, rtld_fini=0x6d90 <_dl_fini>, stack_end=0x103eddc)
    at ../csu/libc-start.c:392
#32 0x080491a8 in ?? ()
(gdb) frame 2
#2  0x025f73e6 in run_event_loop (p=0x103e724) at extensions/libevent.c:218
218     extensions/libevent.c: No such file or directory.
(gdb) p time_units_per_microsec 
$1 = 0
(gdb) p scm_c_time_units_per_second 
$2 = 1000

So I guess we should change:

microsec = data->timeout / time_units_per_microsec;

to:

microsec = (time_units_per_microsec == 0) ? 0 : (data->timeout / time_units_per_microsec);

Thoughts?

[civodul]

Looking at libguile/stime.c, this problem can happen on any 32-bit platform (well, any non-Linux platform; on Linux, it'll use epoll):

#if SCM_SIZEOF_LONG >= 8 && defined HAVE_CLOCK_GETTIME
/* Nanoseconds on 64-bit systems with POSIX timers.  */
#define TIME_UNITS_PER_SECOND 1000000000
#else
/* Milliseconds for everyone else.  */
#define TIME_UNITS_PER_SECOND 1000
#endif