Re: [Valgrind-users] valgrind stack problem

[Ashley P. <as...@qu...>]

On Fri, 2006-10-20 at 11:16 +0100, Julian Seward wrote:
> On Friday 20 October 2006 11:04, Ashley Pittman wrote:
> > On Fri, 2006-10-20 at 10:41 +0100, Julian Seward wrote:
> > > Are you sure you're not trying to allocate too much stuff onto the stack?
> > > 3.2.1 allows you a max stack of 16M and you get to segfault after that.
> >
> > Is this limitation something that's here to stay?  I've not spotted it
> > as a problem but I'm a few months behind head-of-tree currently.
> 
> Well, it's been like that for quite a long time now, probably since 
> 3.1.0 at least.  It's not a recent change.  Is it causing you or
> potentially causing you a problem?  I know that Fortran HPC folks 
> tend to complain about it from time to time as putting huge arrays
> on the stack is apparently a culturally acceptable thing to do in
> Fortran-world, but apart from it doesn't seem to cause many problems.

It's exactly those people I was thinking of, it's not something I do
myself but I have seen stacks measured in Gb.  More of a potential
problem that a real one.

One reproducer I had sent to me recently was this one:

int main() {
  unsigned long eqs[1309732];

  g_elanBaseP = elan_baseInit(0);

  printf ("elan_baseInit returned: %#lx\n", g_elanBaseP);
  return 0;
}

As it turns out in this case the problem was a simple ulimit one but it
goes to show that people really do try some unexpected things.

Valgrind seems to get this mostly right but does complain when
elan_baseInit() tries to read it's parameter (a 64 bit int).  It also
seems to get the line numbers wrong on ia64, base.c only has 864 lines,
857 is the } closing the elan_baseInit() function.

I'll try and get together a reproducer for this second issue.

on ia32 valgrind shows this:

==4376== Warning: client switching stacks?  SP change: 0xBEFFF9E8 -->
0xBEB00934
==4376==          to suppress, use: --max-stackframe=5238964 or greater
==4376== Invalid write of size 4
==4376==    at 0x80484B2: main (test.c:8)
==4376==  Address 0xBEB00934 is on thread 1's stack
==4376== 
==4376== Invalid read of size 4
==4376==    at 0x4063F00: elan_baseInit (base.c:593)
==4376==  Address 0xBEB00934 is on thread 1's stack
==4376== Warning: set address range perms: large range 134225920 (readable)
==4376== Warning: set address range perms: large range 134225920 (readable)
==4376== Warning: set address range perms: large range 134217728 (readable)
==4376== Warning: client switching stacks?  SP change: 0xBEB00930 --> 0xBEFFF9E8
==4376==          to suppress, use: --max-stackframe=5238968 or greater

on ia64 it shows this:

==17920== Warning: client switching stacks?  SP change: 0x7FF0008A0 -->
0x7FE602778
==17920==          to suppress, use: --max-stackframe=10477864 or greater
==17920== Invalid write of size 8
==17920==    at 0x400638: main (test.c:8)
==17920==  Address 0x7FE602778 is on thread 1's stack
==17920== Warning: set address range perms: large range 134225920 (defined)
==17920== Warning: set address range perms: large range 134225920 (defined)
==17920== Warning: set address range perms: large range 134217728 (defined)
==17920== 
==17920== Invalid read of size 8
==17920==    at 0x4B5B5AC: elan_baseInit (base.c:857)
==17920==  Address 0x7FE602778 is on thread 1's stack
==17920== Warning: client switching stacks?  SP change: 0x7FE602780 --> 0x7FF0008A0
==17920==          to suppress, use: --max-stackframe=10477856 or greater
==17920== 

Ashley,