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Re: gdb/2009: Segmentation faults on AMD64
- From: Jeroen Dekkers <jeroen at dekkers dot cx>
- To: gdb-gnats at sources dot redhat dot com, nobody at sources dot redhat dot com, alvaro at alobbs dot com, gdb-prs at sources dot redhat dot com, gdb-patches at sources dot redhat dot com
- Date: Sun, 16 Oct 2005 14:59:23 +0200
- Subject: Re: gdb/2009: Segmentation faults on AMD64
I debugged this segfault and it is caused by incorrect debug
information generated by GCC on AMD64, see http://gcc.gnu.org/PR24400.
The problem is that the filenumbers in the .debug_macinfo arex
wrong. They jump from 0xf to 0x11, skipping 0x10, so the last filename
has a number which isn't in the filename table.
GDB blindly uses the number as index into the filename table,
resulting in a segfault. The following patch adds a check whether the
index isn't bigger than the size of the table.
2005-10-16 Jeroen Dekkers <jeroen@dekkers.cx>
Fix PR gdb/2009.
* dwarf2read.c (file_full_name): Check whether FILE isn't bigger
than the size of the filename table.
Index: dwarf2read.c
===================================================================
RCS file: /cvs/src/src/gdb/dwarf2read.c,v
retrieving revision 1.183
diff -u -p -r1.183 dwarf2read.c
--- dwarf2read.c 1 Aug 2005 04:06:27 -0000 1.183
+++ dwarf2read.c 16 Oct 2005 12:43:23 -0000
@@ -8810,7 +8810,19 @@ dwarf_alloc_die (void)
static char *
file_full_name (int file, struct line_header *lh, const char *comp_dir)
{
- struct file_entry *fe = &lh->file_names[file - 1];
+ struct file_entry *fe;
+
+ /* Check whether FILE isn't bigger than the number of filenames in
+ the table. There used to be a bug in GCC (PR24400) which would
+ generate an index that is one higher than the size of the
+ table. */
+ if (file > lh->num_file_names)
+ {
+ complaint (&symfile_complaints, _("invalid file index number in macro section"));
+ return xstrdup ("/invalid/file/index");
+ }
+
+ fe = &lh->file_names[file - 1];
if (IS_ABSOLUTE_PATH (fe->name))
return xstrdup (fe->name);