Fix sbrk in PIE binaries

In PIE mode, the program gets loaded at very low address, and thus _end is very
low, just before libraries, and thus initializing the brk to it does not make
sense, since there is no room left there. Hardcode the brk to 0x8000000 for now
as a workaround.

Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Gbp-Pq: Topic hurd-i386
Gbp-Pq: Name tg-pie-sbrk.diff

diff --git a/sysdeps/mach/hurd/brk.c b/sysdeps/mach/hurd/brk.c
index f8272e5f225a7ecb026cdc4d54c1acf19c3ac31b..bc95789fb140004a6e7e01300b1fbc8230d6ee52 100644 (file)
--- a/sysdeps/mach/hurd/brk.c
+++ b/sysdeps/mach/hurd/brk.c
@@ -143,8 +143,12 @@ init_brk (void)
   /* If _hurd_brk is already set, don't change it.  The assumption is that
      it was set in a previous run before something like Emacs's unexec was
      called and dumped all the data up to the break at that point.  */
-  if (_hurd_brk == 0)
+  if (_hurd_brk == 0) {
     _hurd_brk = (vm_address_t) &_end;
+    if (_hurd_brk < 0x8000000)
+      /* XXX: PIE case, get out of library area */
+      _hurd_brk = 0x8000000;
+  }
 
   pagend = round_page (_hurd_brk);