OK, here's a trace.  The program is multi-threaded, so I used
strace -f.  Fortunately the problem happens almost right away.
At the very end, you can see the infinite loop starting.
One thing I noticed is that our printf's in the segv handler
are printing the fault
address as 20004000 while the mprotect is giving the address
as 6000000020004000.  This last address seems to be correct in 
relation to the original mprotect for the shared heap, which was

mprotect(0x6000000020000000, 268435456, PROT_NONE) = 0

Please let me know if this tells you anything interesting.

Jay

-----Original Message-----
From: David Mosberger [mailto:davidm@hpl.hp.com]
Sent: Friday, December 07, 2001 11:35 AM
To: Hoeflinger, Jay P
Cc: 'Boehm, Hans'; 'n0ano@indstorage.com'; 'linux-ia64@linuxia64.org'
Subject: RE: [Linux-ia64] mprotect problem


Jay,

If you don't have a minimal test program or can't share the source
code, it might be useful to collect a syscall trace.  That way, we
could see what addresses and sizes are involved in the mprotect()
call.  Something like:

	strace -o /tmp/out PROGNAME

should do (I'm assuming your program is not multithreaded; if it is,
you'd need to use the -f option and make sure you're running the
latest version of strace).

If the resulting output is very big, you won't be able to send it to
the mailing list.  You can either trim the output or just make sure
you mail it to me directly (davidm@hpl.hp.com).

Thanks,

	--david