Very strange bug

Hans Nilsson <>
Fri Nov 22 14:51:06 CET 2002


We are struggeling with "almost exactly" the same problem here.  We are 
running erlang on a powerpc with linux and a flash file system.  

Erlang and our application is started last in the linux boot sequence.

Sometimes, (5-10% of the times), erlang exits and reports {undef,[{M,F ... 
although the file M.erl exists.

The problem seem to dissappear if we first put some of the files into the
file system cache.

We can't yet tell were the problem is due to some problems with strace on 
this very type of PPC.

This problem is present both in latest Erlang PPC-release and earlier
betas. Linux is 2.4.20-pre11. I can't give you more details about versions
of filesystems and processor right now since the guy knowing that is not
here right now.

/Hans Nilsson


On Tue, 19 Nov 2002, Vladimir Sekissov wrote:

> Good day,
> 
> I've discovered a very strange (for me) bug when I'm starting Erlang
> with clean boot without sasl.
> 
> Lets explain by example:
> 
> $ /usr/local/bin/erl
> 
> Eshell V5.2  (abort with ^G)
> 1> m(file).
> 
> Module file compiled: Date: October 24 2002, Time: 11.26
> Compiler options:  [v3,
>                     debug_info,
>                     {i,"../include"},
>                     {outdir,"../ebin"},
>                     {cwd,"/usr/local/src/otp_src_R9B-0/lib/kernel/src"}]
> Object file: /usr/local/lib/erlang/lib/kernel-2.8.0/ebin/file.beam
> Exports: 
> ... skipped...
> eval/1                        read/2
> file_info/1                   read_file/1
> format_error/1                read_file_info/1
> ... skipped...
> 
> 2> file:read_file("./www/HEAD").
> {ok, ...}
> 
> 3> yaws:start().
> 
> =INFO REPORT==== 19-Nov-2002::02:57:09 ===
> Using config file /home/svg/yaws.conf
> =INFO REPORT==== 19-Nov-2002::02:57:09 ===
> Listening to 127.0.0.1:8000 for servers ["localhost:8000"]
> ok
> 
> 4> m(file).
> ... skipped...
> eval/1                        rawopen/2
> file_info/1                   read/2
> format_error/1                read_file_info/1
> get_cwd/0                     read_link/1
> ... skipped...
> 
> 5> file:read_file("./www/HEAD").
> ** exited: {undef,[{file,read_file,
>                          ["./www/HEAD"]},
>                    {erl_eval,expr,3},
>                    {erl_eval,exprs,4},
>                    {shell,eval_loop,2}]} **
> 
> 
> As you can see in second output of m(file) declaration of read_file/1
> is absent and function is not available.
> 
> When I'm starting Erlang with sasl all is ok.
> 
> Can somebody point me to the cause of the problem.
> 
> The system is GentooLinux-1.4/GCC-3.1/kernel-2.4.19
> 
> Best Regards,
> Vladimir Sekissov
> 





More information about the erlang-questions mailing list