Re: [PATCH 03/24] x86: Do not free zero sized per cpu areas

[Johannes Weiner <hannes@cmpxchg.org>]

On Fri, Mar 26, 2010 at 04:49:10PM -0700, Yinghai Lu wrote:
> On 03/26/2010 04:42 PM, Johannes Weiner wrote:
> > On Fri, Mar 26, 2010 at 03:21:33PM -0700, Yinghai Lu wrote:
> >> From: Ian Campbell <ian.campbell@citrix.com>
> >>
> >> This avoids an infinite loop in free_early_partial().
> >>
> >> Add a warning to free_early_partial to catch future problems.
> >>
> >> -v5: put back start > end back into WARN_ONCE()
> >> -v6: use one line for warning according to linus
> >> -v7: more test by
> >>
> >> Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
> >> Signed-off-by: Yinghai Lu <yinghai@kernel.org>
> >> Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> >> Tested-by: Joel Becker <joel.becker@oracle.com>
> >> Tested-by: Stanislaw Gruszka <sgruszka@redhat.com>
> >> Cc: Peter Zijlstra <peterz@infradead.org>
> >> Cc: Ingo Molnar <mingo@elte.hu>
> >> ---
> >>  kernel/early_res.c |    6 ++++++
> >>  1 files changed, 6 insertions(+), 0 deletions(-)
> >>
> >> diff --git a/kernel/early_res.c b/kernel/early_res.c
> >> index 3cb2c66..69bed5b 100644
> >> --- a/kernel/early_res.c
> >> +++ b/kernel/early_res.c
> >> @@ -333,6 +333,12 @@ void __init free_early_partial(u64 start, u64 end)
> >>  	struct early_res *r;
> >>  	int i;
> >>  
> >> +	if (start == end)
> >> +		return;
> >> +
> >> +	if (WARN_ONCE(start > end, "free_early_partial: wrong range [%#llx, %#llx]\n", start, end))
> >> +		return;
> > 
> > I think you can drop the function name, it will be in the stack dump
> > anyway.  And that would get the line back into bounds :)
> > 
> > Other than that,
> > Acked-by: Johannes Weiner <hannes@cmpxchg.org>
> 
> Thanks.
> 
> is there any chance that dump stack only print out address instead of function name ?

I suppose so, lacking frame pointers, but you still have
filename + linenumber + 'wrong range'.