Re: PR3498: more efficient dwfl searching

[Josh Stone <jistone at redhat dot com>]

On 07/15/2009 02:18 AM, Wenji Huang wrote:
> Wenji Huang wrote:
>> I found one regression since this commit.
>>
>> $ stap -l nfsd.create*
>> Segmentation fault
>> [78375.044067] <6>stap[24911]: segfault at 0 ip 0000000000480efb sp 
>> 00007ffffe706400 error 4 in stap[400000+142000]

Works for me -- can you provide more details about your configuration?

> Seems that checking dw can resolve the error. Did some tests, work fine.
> 
> diff --git a/tapsets.cxx b/tapsets.cxx
> index 9ca25b0..71dd0d9 100644
> --- a/tapsets.cxx
> +++ b/tapsets.cxx
> @@ -3457,6 +3457,9 @@ dwarf_builder::build(systemtap_session & sess,
>     if (sess.verbose > 3)
>       clog << "dwarf_builder::build for " << module_name << endl;
> 
> +  if(!dw)
> +    return;
> +
>     string mark_name;
>     if (get_param(parameters, TOK_MARK, mark_name))
>       {

It should not be possible for dw to come out NULL, so I would rather not
paper over this.  Can you root cause how this happened?

Thanks,

Josh