From 220f16cab6c40a1b0df1a5d2101c6602abbc6aae Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Tue, 6 Aug 2019 18:39:20 -0700 Subject: [PATCH] Re-port dump_bitset_clear to -fsanitize=undefined * src/pdumper.c (dump_bitset_clear): Skip the memset if the size is zero, because in that case the destination might be NULL. This fixes a bug introduced in 2019-07-26T06:17:52Zeggert@cs.ucla.edu. Add a comment to make the bug less likely to reoccur. --- src/pdumper.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/src/pdumper.c b/src/pdumper.c index e0ddc1c8088..326a346a632 100644 --- a/src/pdumper.c +++ b/src/pdumper.c @@ -4931,7 +4931,10 @@ dump_bitset_set_bit (struct dump_bitset *bitset, size_t bit_number) static void dump_bitset_clear (struct dump_bitset *bitset) { - memset (bitset->bits, 0, bitset->number_words * sizeof bitset->bits[0]); + /* Skip the memset if bitset->number_words == 0, because then bitset->bits + might be NULL and the memset would have undefined behavior. */ + if (bitset->number_words) + memset (bitset->bits, 0, bitset->number_words * sizeof bitset->bits[0]); } struct pdumper_loaded_dump_private -- 2.39.2