On Wed, Apr 29, 2026 at 01:29:18PM -0600, Gustavo A. R. Silva wrote:
> + /*
> + * Intel LBR bits
> + */
> + int lbr_users;
> + int lbr_pebs_users;
> + union {
> + struct er_account *lbr_sel;
> + struct er_account *lbr_ctl;
> + };
> + u64 br_sel;
> + void *last_task_ctx;
> + int last_log_id;
> + int lbr_select;
> + void *lbr_xsave;
> +
> + /* Must be last as it ends in a flexible-array member. */
> + TRAILING_OVERLAP(struct perf_branch_stack, lbr_stack, entries,
> + struct perf_branch_entry lbr_entries[MAX_LBR_ENTRIES];
> + u64 lbr_counters[MAX_LBR_ENTRIES];
> /* branch stack extra */
> + );
FWIW, this thing is horrible crap. Per construction this thing does not
need to be last at all, you can have multiple such constructs in a
single structure and things would be perfectly fine.
Also, your TRAILING_OVERLAP() thing should probably have
__no_randomize_layout in ATTRS, rather than empty (and I'm assuming
__packed implies __no_randomized_layout, otherwise 'fun' things can
happen).
> };
