On Mon, May 16, 2022 at 9:53 AM Martin Liška <mli...@suse.cz> wrote: > > Fixes: > opts-global.cc:75:15: runtime error: store to address 0x00000bc9be70 with > insufficient space for an object of type 'char' > which happens when mask == 0, len == 0 and we allocate zero elements. > Eventually, result[0] is called which triggers the UBSAN. > > It's newly discovered after the Siddhesh's recent patch. > > Cheers, > Martin > > gcc/ChangeLog: > > * opts-global.cc (write_langs): Allocate at least one byte. > --- > gcc/opts-global.cc | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/gcc/opts-global.cc b/gcc/opts-global.cc > index a18c76940f9..4f5f8cdcb98 100644 > --- a/gcc/opts-global.cc > +++ b/gcc/opts-global.cc > @@ -61,7 +61,7 @@ write_langs (unsigned int mask) > if (mask & (1U << n)) > len += strlen (lang_name) + 1; > > - result = XNEWVEC (char, len); > + result = XNEWVEC (char, MAX (1, len));
Does it not fail to allocate space for the '\0' it terminates the list with even when there's a language? Ah, it "re-uses" the byte it allocates for the '/' of the first element. Can you add a comment? OK with that change. Richard. > len = 0; > for (n = 0; (lang_name = lang_names[n]) != 0; n++) > if (mask & (1U << n)) > -- > 2.36.1 >
