Re: COMPAT_40 broken in current amd64 kernel?

[David Young <dyoung%pobox.com@localhost>]

On Sat, Mar 13, 2010 at 06:05:42AM -0800, Paul Goyette wrote:
> On Sun, 7 Mar 2010, Paul Goyette wrote:
> 
> >On Sun, 7 Mar 2010, Christos Zoulas wrote:
> >
> >>>However, on a kernel built today, it gives me a core dump due to a "bad
> >>>system call".  The backtrace shows that this is the code leading up to
> >>>the bad syscall:
> >>>
> >>>(gdb) x/10i 0x47a598
> >>>0x47a598:       jmpq   0x490ba0
> >>>0x47a59d:       data16
> >>>0x47a59e:       data16
> >>>0x47a59f:       nop
> >>>0x47a5a0:       mov    $0x74,%eax
> >>>0x47a5a5:       mov    %rcx,%r10
> >>>0x47a5a8:       syscall
> >>>0x47a5aa:       jb     0x47a598
> >>>0x47a5ac:       retq
> >>>0x47a5ad:       nop
> >>>(gdb)
> >>>
> >>
> >>0x74 == 116 is the old gettimeofday. Something is not loading compat_50.
> >
> >Well, as I indicated, COMPAT_50 (and COMPAT_40) were both built-in
> >to both kernels in question, so it shouldn't be a matter of
> >"loading".
> 
> Hmmm, things get more and more interesting...
> 
> The problem reappeared this morning, after the system and the
> program in question had been running for several days!
> 
> Even more interesting is, when I tried to re-run the program I got a
> kernel crash!  (Unfortunately, this is amd64, so I did not get a
> system core dump.)  In the previous instance of this problem,
> re-running the program simply resulted in another user-mode core
> dump.

I have some funny compat problems that began when I updated from 5.99.23-ish
to 5.99.24 sources of a few days ago.  In /var/log/messages:

Mar 10 16:35:16 elmendorf /netbsd: WARNING: module error: use -f to reinstate bu
iltin module "compat"

modstat says:

NAME             CLASS      SOURCE     REFS  SIZE     REQUIRES
bpf              driver     builtin    0     -        -
compat           misc       builtin    -1    -        -
coredump         misc       filesys    1     3064     -
exec_elf32       misc       filesys    0     7165     coredump
exec_script      misc       filesys    0     1187     -
ffs              vfs        boot       0     166036   -
nfs              vfs        filesys    1     145547   -
nfsserver        misc       filesys    0     85064    nfs
secmodel_bsd44   secmodel   builtin    -1    -        suser,securelevel
securelevel      secmodel   builtin    0     -        -
suser            secmodel   builtin    0     -        -

-1 refs?!

Dave

-- 
David Young             OJC Technologies
dyoung%ojctech.com@localhost      Urbana, IL * (217) 278-3933