From FEDORA_PATCHES Mon Sep 17 00:00:00 2001 From: Sergio Durigan Junior Date: Fri, 10 May 2019 16:57:26 -0400 Subject: gdb-rhbz1708192-parse_macro_definition-crash.patch ;; "Fix" segfault that happens on parse_macro_definition because ;; debugedit corrupts the .debug_macro section. ;; Sergio Durigan Junior, RH BZ 1708192. Don't crash if dwarf_decode_macro_bytes's 'body' is NULL Hi, Ref.: https://bugzilla.redhat.com/show_bug.cgi?id=1708192 https://bugzilla.redhat.com/show_bug.cgi?id=1708786 During the Fedora RPM build process, gdb-add-index is invoked to extract the DWARF index from the binary, and GDB will segfault because dwarf2read.c:parse_definition_macro's 'body' variable is NULL. The underlying problem is that Fedora's rpm-build's "debugedit" program will silently corrupt .debug_macro strings when a binary is compiled with -g3. This is being taken care of by Mark Wielaard, here: https://bugzilla.redhat.com/show_bug.cgi?id=1708786 However, I still feel it's important to make GDB more resilient against invalid DWARF input, so I'm proposing this rather simple patch to catch the situation when "body == NULL" (i.e., it's probably been corrupted) and issue a complaint. This is not a real fix to the problem, of course, but at least GDB is able to finish without segfaulting. OK for master? gdb/ChangeLog: 2019-05-15 Sergio Durigan Junior Ref.: https://bugzilla.redhat.com/show_bug.cgi?id=1708192 * dwarf2read.c (dwarf_decode_macro_bytes): Check whether 'body' is NULL, and complain if that's the case. diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c --- a/gdb/dwarf2read.c +++ b/gdb/dwarf2read.c @@ -24355,7 +24355,21 @@ dwarf_decode_macro_bytes (struct dwarf2_per_objfile *dwarf2_per_objfile, is_define ? _("definition") : _("undefinition"), line == 0 ? _("zero") : _("non-zero"), line, body); - if (is_define) + if (body == NULL) + { + /* Fedora's rpm-build's "debugedit" binary + corrupted .debug_macro sections. + + For more info, see + https://bugzilla.redhat.com/show_bug.cgi?id=1708786 */ + complaint (_("debug info gives %s invalid macro %s " + "without body (corrupted?) at line %d " + "on file %s"), + at_commandline ? _("command-line") : _("in-file"), + is_define ? _("definition") : _("undefinition"), + line, current_file->filename); + } + else if (is_define) parse_macro_definition (current_file, line, body); else {