From f2423983a8f4b5eba77b1d8510be022d600714b6 Mon Sep 17 00:00:00 2001 From: Simon Marchi Date: Fri, 21 Oct 2022 09:08:03 -0400 Subject: [PATCH] gdb: check for empty offsets vector in inherit_abstract_dies When building GDB with clang and --enable-ubsan, I get: UNRESOLVED: gdb.dwarf2/frame-inlined-in-outer-frame.exp: starti prompt The cause being: $ ./gdb --data-directory=data-directory -nx -q -readnow testsuite/outputs/gdb.dwarf2/frame-inlined-in-outer-frame/frame-inlined-in-outer-frame Reading symbols from testsuite/outputs/gdb.dwarf2/frame-inlined-in-outer-frame/frame-inlined-in-outer-frame... Expanding full symbols from testsuite/outputs/gdb.dwarf2/frame-inlined-in-outer-frame/frame-inlined-in-outer-frame... /home/simark/src/binutils-gdb/gdb/dwarf2/read.c:11954:47: runtime error: applying non-zero offset 8 to null pointer I found this to happen with ld-linux on at least Arch Linux and Ubuntu 22.04: $ ./gdb --data-directory=data-directory -nx -q -readnow -iex "set debuginfod enabled on" /lib64/ld-linux-x86-64.so.2 Reading symbols from /lib64/ld-linux-x86-64.so.2... Reading symbols from /home/simark/.cache/debuginfod_client/22bd7a2c03d8cfc05ef7092bfae5932223189bc1/debuginfo... Expanding full symbols from /home/simark/.cache/debuginfod_client/22bd7a2c03d8cfc05ef7092bfae5932223189bc1/debuginfo... /home/simark/src/binutils-gdb/gdb/dwarf2/read.c:11954:47: runtime error: applying non-zero offset 8 to null pointer The problem happens when doing this: sect_offset *offsetp = offsets.data () + 1 When `offsets` is an empty vector, `offsets.data ()` returns nullptr. Fix it by wrapping that in a `!offsets.empty ()` check. Change-Id: I6d29ba2fe80ba4308f68effd9c57d4ee8d67c29f Approved-By: Tom Tromey --- gdb/dwarf2/read.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c index cde7a5bd01f..077af064663 100644 --- a/gdb/dwarf2/read.c +++ b/gdb/dwarf2/read.c @@ -11949,17 +11949,22 @@ inherit_abstract_dies (struct die_info *die, struct dwarf2_cu *cu) corresponding_abstract_child = corresponding_abstract_child->sibling; } - std::sort (offsets.begin (), offsets.end ()); - sect_offset *offsets_end = offsets.data () + offsets.size (); - for (sect_offset *offsetp = offsets.data () + 1; - offsetp < offsets_end; - offsetp++) - if (offsetp[-1] == *offsetp) - complaint (_("Multiple children of DIE %s refer " - "to DIE %s as their abstract origin"), - sect_offset_str (die->sect_off), sect_offset_str (*offsetp)); + if (!offsets.empty ()) + { + std::sort (offsets.begin (), offsets.end ()); + sect_offset *offsets_end = offsets.data () + offsets.size (); + for (sect_offset *offsetp = offsets.data () + 1; + offsetp < offsets_end; + offsetp++) + if (offsetp[-1] == *offsetp) + complaint (_("Multiple children of DIE %s refer " + "to DIE %s as their abstract origin"), + sect_offset_str (die->sect_off), + sect_offset_str (*offsetp)); + } sect_offset *offsetp = offsets.data (); + sect_offset *offsets_end = offsets.data () + offsets.size (); die_info *origin_child_die = origin_die->child; while (origin_child_die != nullptr && origin_child_die->tag != 0) { -- 2.30.2