> On Fri, 14 Nov 2014 08:44:12 -0500, kan liang wrote:
> > + /* LBR only affects the user callchain */
> > + if (i != chain_nr) {
> > + struct branch_stack *lbr_stack = sample-
> >branch_stack;
> > + int lbr_nr = lbr_stack->nr;
> > + /*
> > + * LBR callstack can only get user call chain.
> > + * The mix_chain_nr is kernel call chain
> > + * number plus LBR user call chain number.
> > + * i is kernel call chain number,
> > + * 1 is PERF_CONTEXT_USER,
> > + * lbr_nr + 1 is the user call chain number.
> > + * For details, please refer to the comments
> > + * in callchain__printf
> > + */
> > + int mix_chain_nr = i + 1 + lbr_nr + 1;
> > +
> > + if (mix_chain_nr > PERF_MAX_STACK_DEPTH) {
> > + pr_warning("corrupted callchain.
> skipping...\n");
> > + return 0;
> > + }
>
> I'm not sure whether this is really a corrupted callchain. If a single chain
> is
> greater than the max it should be corrupted, but we're now summing up
> with other values..
>
> What about checking callchain_nr and lbr_nr separately or mix_nr with
> 2*max?
The lbr_nr max is 16. I will change it to max+16.
Thanks,
Kan
>
> Thanks,
> Namhyung
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