On 2026-06-21, David Laight wrote: > The same could be done for nslot - any value above 64k is pretty much > guaranteed to be garbage
I took that up in v2, but it does not hold against the code, so v3 drops it. The allocation it was meant to bound -- ndd->data in nd_label_data_init() -- is kvzalloc(config_size), not nslot-derived, so capping nslot shrinks nothing. And the cap is unsafe: on ND_NSINDEX_INIT the kernel writes nslot = nvdimm_num_label_slots(ndd) = config_size / label_size, which is above 64K once config_size is past ~8.4MB. A 64K cap then rejects labels the kernel itself wrote, so a freshly-formatted large device fails its own next probe. The (u64) cast in patch 1 already makes the bound exact, so the overflow is closed without the cap. v3 keeps the cast; the labelsize-shift UB the review also turned up is a separate fix, not a stand-in for the cap. Thanks, Bryam
