Hello Dave Hansen,
The patch 5f23f6d082a9: "x86/pkeys: Add self-tests" from Jul 29,
2016, leads to the following Smatch static checker warning:
tools/testing/selftests/vm/protection_keys.c:647 record_pkey_malloc()
warn: address of 'pkey_malloc_records[i]' is probably non-NULL
tools/testing/selftests/vm/protection_keys.c
638 long nr_pkey_malloc_records;
639 void record_pkey_malloc(void *ptr, long size, int prot)
640 {
641 long i;
642 struct pkey_malloc_record *rec = NULL;
643
644 for (i = 0; i < nr_pkey_malloc_records; i++) {
645 rec = &pkey_malloc_records[i];
646 /* find a free record */
--> 647 if (rec)
648 break;
649 }
650 if (!rec) {
This code is supposed re-allocate memory. If we run out, then allocate
2x the memory. But it only works for the first allocation where
"pkey_malloc_records" is NULL.
For the following allocations it will just select &pkey_malloc_records[0]
and re-use that again.
651 /* every record is full */
652 size_t old_nr_records = nr_pkey_malloc_records;
653 size_t new_nr_records = (nr_pkey_malloc_records * 2 + 1);
654 size_t new_size = new_nr_records * sizeof(struct pkey_malloc_record);
655 dprintf2("new_nr_records: %zd\n", new_nr_records);
656 dprintf2("new_size: %zd\n", new_size);
657 pkey_malloc_records = realloc(pkey_malloc_records, new_size);
658 pkey_assert(pkey_malloc_records != NULL);
659 rec = &pkey_malloc_records[nr_pkey_malloc_records];
660 /*
661 * realloc() does not initialize memory, so zero it from
662 * the first new record all the way to the end.
663 */
664 for (i = 0; i < new_nr_records - old_nr_records; i++)
665 memset(rec + i, 0, sizeof(*rec));
666 }
667 dprintf3("filling malloc record[%d/%p]: {%p, %ld}\n",
668 (int)(rec - pkey_malloc_records), rec, ptr, size);
669 rec->ptr = ptr;
670 rec->size = size;
671 rec->prot = prot;
672 pkey_last_malloc_record = rec;
673 nr_pkey_malloc_records++;
674 }
regards,
dan carpenter
