From 3fa23bb5a5320dd82d32455036d59a026929fc2f Mon Sep 17 00:00:00 2001 From: Tom de Vries Date: Fri, 8 Jul 2022 15:56:06 +0200 Subject: [PATCH] [gdb/symtab] Fix segfault in dwarf2_per_objfile::symtab_set_p When running test-case gdb.cp/cpexprs-debug-types.exp with target board cc-with-debug-names, I run into: ... (gdb) print base::operator new^M ^M ^M Fatal signal: Segmentation fault^M ----- Backtrace -----^M 0x57ea46 gdb_internal_backtrace_1^M /home/vries/gdb_versions/devel/src/gdb/bt-utils.c:122^M 0x57eae9 _Z22gdb_internal_backtracev^M /home/vries/gdb_versions/devel/src/gdb/bt-utils.c:168^M 0x75b8ad handle_fatal_signal^M /home/vries/gdb_versions/devel/src/gdb/event-top.c:946^M 0x75ba19 handle_sigsegv^M /home/vries/gdb_versions/devel/src/gdb/event-top.c:1019^M 0x7f795f46a8bf ???^M 0x6d3cb1 _ZNK18dwarf2_per_objfile12symtab_set_pEPK18dwarf2_per_cu_data^M /home/vries/gdb_versions/devel/src/gdb/dwarf2/read.c:1515^M ... The problem is in this piece of code in dw2_debug_names_iterator::next: ... case DW_IDX_type_unit: /* Don't crash on bad data. */ if (ull >= per_bfd->tu_stats.nr_tus) { complaint (_(".debug_names entry has bad TU index %s" " [in module %s]"), pulongest (ull), objfile_name (objfile)); continue; } per_cu = per_bfd->get_cu (ull + per_bfd->tu_stats.nr_tus); break; ... The all_comp_units vector (which get_cu accesses) contains both CUs and TUs, with CUs first. So to get the nth TU we need the element at "nr_cus + n", but the code uses "nr_tus + n" instead. Fix this by using "nr_cus + n". Tested on x86_64-linux. Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29334 --- gdb/dwarf2/read.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c index 23fe5679cbd..9f92b420645 100644 --- a/gdb/dwarf2/read.c +++ b/gdb/dwarf2/read.c @@ -4991,7 +4991,11 @@ dw2_debug_names_iterator::next () objfile_name (objfile)); continue; } - per_cu = per_bfd->get_cu (ull + per_bfd->tu_stats.nr_tus); + { + int nr_cus = (per_bfd->all_comp_units.size () + - per_bfd->tu_stats.nr_tus); + per_cu = per_bfd->get_cu (nr_cus + ull); + } break; case DW_IDX_die_offset: /* In a per-CU index (as opposed to a per-module index), index -- 2.30.2