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?
Thanks,
Namhyung
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