On 2025-04-16 05:00, Jan Beulich wrote:
By observation GNU ld 2.25 may emit file symbols for .data.read_mostly when linking xen.efi. Due to the nature of file symbols in COFF symbol tables (see the code comment) the symbols_offsets[] entries for such symbols would cause assembler warnings regarding value truncation. Of course the resulting entries would also be both meaningless and useless. Add a heuristic to get rid of them, really taking effect only when --all-symbols is specified (otherwise these symbols are discarded anyway).Signed-off-by: Jan Beulich <jbeul...@suse.com> --- Factor 2 may in principle still be too small: We zap what looks like real file symbols already in read_symbol(), so table_cnt doesn't really reflect the number of symbol table entries encountered. It has proven to work for me in practice though, with still some leeway left. --- a/xen/tools/symbols.c +++ b/xen/tools/symbols.c @@ -213,6 +213,16 @@ static int symbol_valid(struct sym_entry if (strstr((char *)s->sym + offset, "_compiled.")) return 0;+ /* At least GNU ld 2.25 may emit bogus file symbols referencing a+ * section name while linking xen.efi. In COFF symbol tables the + * "value" of file symbols is a link (symbol table index) to the next + * file symbol. Since file (and other) symbols (can) come with one + * (or in principle more) auxiliary symbol table entries, the value in + * this heuristic is bounded to twice the number of symbols we have + * found. See also read_symbol() as to the '?' checked for here. */ + if (s->sym[0] == '?' && s->sym[1] == '.' && s->addr < table_cnt * 2) + return 0; + return 1; }
I looked at this. It'll drop symbols, but I don't know enough to give an R-b. I can't give an actionable A-b either. Maybe someone else can chime in.
Maybe this is just showing my lack of knowledge, but could any symbol starting "?." be considered invalid? I don't think I've ever seen any like that.
Regards, Jason
