[erlang-bugs] Floating point exception (core dumped) in beam

[Maximillian Dornseif]

Mikael Pettersson-3 wrote:
> 
> The kernel reports SIGFPE on return from syscall 0x17e.
> This looks like a kernel or libc bug.
> 
> Possibly the kernel expects FP exceptions to be masked
> and cannot handle user-space (BEAM) having enabled them.
> You can test that theory by editing erts/configure: find
> fpe-test.c in erts/configure, place a "return 1;" at the
> start of main(), run ./configure, ensure that it says that
> floating-point exceptions are unreliable, make the system,
> and run the test case again.
> 

I changed the configure script an got

checking for unreliable floating point execptions... unreliable; testing in
software instead

I then compiled, installed an retried the testcase - and  got the same issue
and more or less the same coredump.



Mikael Pettersson-3 wrote:
> 
> If things now work then this
> system needs to be blacklisted (due to apparent kernel/libc
> bugs) from using FP exceptions.
> 

I checked on FreeBSD 6.2 by copying the .beam files and the Mnedia directory
to an Machine running FreeBSD 6.2 and I can't trigger the issue there. But
maybe this is related to the CPU and not to the OS.

$ uname -a   
FreeBSD boingball.XXX 6.2-RELEASE FreeBSD 6.2-RELEASE #0: Fri Jan 12
10:40:27 UTC 2007    
root@REDACTED:/usr/obj/usr/src/sys/GENERIC  i386
FreeBSD is a registered trademark of The FreeBSD Foundation.
FreeBSD 6.2-RELEASE #0: Fri Jan 12 10:40:27 UTC 2007
    root@REDACTED:/usr/obj/usr/src/sys/GENERIC
ACPI APIC Table: <PTLTD  	 APIC  >
Timecounter "i8254" frequency 1193182 Hz quality 0
CPU: Intel(R) Pentium(R) 4 CPU 2.26GHz (2259.15-MHz 686-class CPU)
  Origin = "GenuineIntel"  Id = 0xf27  Stepping = 7
 
Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>
  Features2=0x4400<CNTX-ID,<b14>>
real memory  = 266862592 (254 MB)
avail memory = 251543552 (239 MB)

Regards

Maximillian
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