Cc'ing Alex. On 9/3/19 9:19 PM, Josh Kunz via Qemu-devel wrote: > The `Data` and `Code` flags in `qOffsets` are actually section offsets > rather than segment offsets. GDB relocates the symbols in those sections > relative to their location in the binary. So we have to use `load_bias`. > > See here for a more detailed description: > https://sourceware.org/gdb/onlinedocs/gdb/General-Query-Packets.html#General-Query-Packets
Maybe we can amend a reference to http://sourceware.org/gdb/onlinedocs/gdb/General-Query-Packets.html#index-qOffsets-packet in the commit. Reviewed-by: Philippe Mathieu-Daudé <phi...@redhat.com> > On Mon, Aug 26, 2019 at 1:29 AM Laurent Vivier <laur...@vivier.eu> wrote: > >> Le 17/08/2019 à 01:34, Josh Kunz via Qemu-devel a écrit : >>> This is needed to support debugging PIE ELF binaries running under QEMU >>> user mode. Currently, `code_offset` and `data_offset` remain unset for >>> all ELF binaries, so GDB is unable to correctly locate the position of >>> the binary's text and data. >>> >>> The fields `code_offset`, and `data_offset` were originally added way >>> back in 2006 to support debugging of bFMT executables (978efd6aac6), >>> and support was just never added for ELF. Since non-PIE binaries are >>> loaded at exactly the address specified in the binary, GDB does not need >>> to relocate any symbols, so the buggy behavior is not normally observed. >>> >>> Buglink: https://bugs.launchpad.net/qemu/+bug/1528239 >>> Signed-off-by: Josh Kunz <j...@google.com> >>> --- >>> linux-user/elfload.c | 2 ++ >>> 1 file changed, 2 insertions(+) >> >> As it seems they are text and data segment offsets, why it's not based >> on info->start_code and info->start_data? >> >> Thanks, >> Laurent >>