[PATCH] Fix _dl_next_tls_modid (was Re: Inconsistency detected by ld.so: ../sysdeps/generic/dl-tls.c: 75: _dl_next_tls_modid: Assertion `result <= _rtld_local._dl_tls_max_dtv_idx' failed!)

[Jakub Jelinek <jakub at redhat dot com>]

On Sun, Mar 13, 2005 at 09:39:04PM +0200, Martin Schlemmer wrote:
> Basically the issue above.  This is valid for glibc 2.3.[234] if I did
> not miss anything.  Here is a good test case:
> 
> http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=219352#msg122
> 
> I came up with attached patch that seems to work and passes all the
> tests (except for the one or two usual ones).  Is this the correct fix,
> or are the problem deeper?

That patch certainly doesn't apply to neither HEAD nor glibc-2_3-branch,
see especially:
2005-01-10  Ulrich Drepper  <drepper@redhat.com>

        * sysdeps/generic/dl-tls.c (_dl_next_tls_modid): Fix assertion and
        recognition of last entry.

The fix can either be that dl-open.c only sets GL(dl_tls_dtv_gaps)
to true if GL(dl_tls_static_nelem) < GL(dl_tls_max_dtv_idx)
(if it is equal, there are certainly no gaps), or handling that case
in _dl_next_tls_modid.  In _dl_next_tls_modid, the choices are either
to do what the patch below does, i.e. just clear GL(dl_tls_dtv_gaps)
if that happens, or just change the assert and let the do ... while
loop run, it shouldn't increment result anyway.

2005-03-15  Jakub Jelinek  <jakub@redhat.com>

	[BZ#786]
	* sysdeps/generic/dl-tls.c (_dl_next_tls_modid): Handle
	GL(dl_tls_static_nelem) == GL(dl_tls_max_dtv_idx).
	* elf/Makefile: Add rules to build and run tst-tls15.
	* elf/tst-tls15.c: New test.
	* elf/tst-tlsmod15a.c: New file.
	* elf/tst-tlsmod15b.c: New file.

--- libc/sysdeps/generic/dl-tls.c.jj	2005-02-25 14:45:06.000000000 +0100
+++ libc/sysdeps/generic/dl-tls.c	2005-03-15 15:36:55.593127093 +0100
@@ -71,26 +71,24 @@ _dl_next_tls_modid (void)
 	 NB: the offset +1 is due to the fact that DTV[0] is used
 	 for something else.  */
       result = GL(dl_tls_static_nelem) + 1;
-      /* If the following would not be true we mustn't have assumed
-	 there is a gap.  */
-      assert (result <= GL(dl_tls_max_dtv_idx));
-      do
-	{
-	  while (result - disp < runp->len)
-	    {
-	      if (runp->slotinfo[result - disp].map == NULL)
-		break;
-
-	      ++result;
-	      assert (result <= GL(dl_tls_max_dtv_idx) + 1);
-	    }
-
-	  if (result - disp < runp->len)
-	    break;
-
-	  disp += runp->len;
-	}
-      while ((runp = runp->next) != NULL);
+      if (result <= GL(dl_tls_max_dtv_idx))
+	do
+	  {
+	    while (result - disp < runp->len)
+	      {
+		if (runp->slotinfo[result - disp].map == NULL)
+		  break;
+
+		++result;
+		assert (result <= GL(dl_tls_max_dtv_idx) + 1);
+	      }
+
+	    if (result - disp < runp->len)
+	      break;
+
+	    disp += runp->len;
+	  }
+	while ((runp = runp->next) != NULL);
 
       if (result > GL(dl_tls_max_dtv_idx))
 	{
--- libc/elf/Makefile.jj	2005-03-08 22:09:39.000000000 +0100
+++ libc/elf/Makefile	2005-03-15 15:17:02.105752389 +0100
@@ -158,7 +158,7 @@ tests += loadtest restest1 preloadtest l
 	 neededtest3 neededtest4 unload2 lateglobal initfirst global \
 	 restest2 next dblload dblunload reldep5 reldep6 reldep7 reldep8 \
 	 circleload1 tst-tls3 tst-tls4 tst-tls5 tst-tls6 tst-tls7 tst-tls8 \
-	 tst-tls10 tst-tls11 tst-tls12 tst-tls13 tst-tls14 tst-align \
+	 tst-tls10 tst-tls11 tst-tls12 tst-tls13 tst-tls14 tst-tls15 tst-align \
 	 tst-align2 $(tests-execstack-$(have-z-execstack)) tst-dlmodcount \
 	 tst-dlopenrpath tst-deep1 tst-dlmopen1 tst-dlmopen2 tst-dlmopen3 \
 	 unload3 unload4 unload5 tst-audit1 tst-global1
@@ -189,6 +189,7 @@ modules-names = testobj1 testobj2 testob
 		tst-tlsmod5 tst-tlsmod6 tst-tlsmod7 tst-tlsmod8 \
 		tst-tlsmod9 tst-tlsmod10 tst-tlsmod11 tst-tlsmod12 \
 		tst-tlsmod13 tst-tlsmod13a tst-tlsmod14a tst-tlsmod14b \
+		tst-tlsmod15a tst-tlsmod15b \
 		circlemod1 circlemod1a circlemod2 circlemod2a \
 		circlemod3 circlemod3a \
 		reldep8mod1 reldep8mod2 reldep8mod3 \
@@ -469,6 +470,7 @@ tst-tlsmod10.so-no-z-defs = yes
 tst-tlsmod12.so-no-z-defs = yes
 tst-tlsmod14a.so-no-z-defs = yes
 tst-tlsmod14b.so-no-z-defs = yes
+tst-tlsmod15a.so-no-z-defs = yes
 circlemod2.so-no-z-defs = yes
 circlemod3.so-no-z-defs = yes
 circlemod3a.so-no-z-defs = yes
@@ -681,8 +683,11 @@ $(objpfx)tst-tls12: $(objpfx)tst-tlsmod1
 $(objpfx)tst-tls13: $(libdl)
 $(objpfx)tst-tls13.out: $(objpfx)tst-tlsmod13a.so
 
-$(objpfx)tst-tls14:  $(objpfx)tst-tlsmod14a.so $(libdl)
-$(objpfx)tst-tls14.out:$(objpfx)tst-tlsmod14b.so
+$(objpfx)tst-tls14: $(objpfx)tst-tlsmod14a.so $(libdl)
+$(objpfx)tst-tls14.out: $(objpfx)tst-tlsmod14b.so
+
+$(objpfx)tst-tls15: $(libdl)
+$(objpfx)tst-tls15.out: $(objpfx)tst-tlsmod15a.so $(objpfx)tst-tlsmod15b.so
 
 CFLAGS-tst-align.c = $(stack-align-test-flags)
 CFLAGS-tst-align2.c = $(stack-align-test-flags)
--- libc/elf/tst-tls15.c.jj	2005-03-15 15:06:07.000474699 +0100
+++ libc/elf/tst-tls15.c	2005-03-15 15:09:43.096964047 +0100
@@ -0,0 +1,32 @@
+#include <dlfcn.h>
+#include <stdio.h>
+
+static int
+do_test (void)
+{
+  void *h = dlopen ("tst-tlsmod15a.so", RTLD_NOW);
+  if (h != NULL)
+    {
+      puts ("unexpectedly succeeded to open tst-tlsmod15a.so");
+      exit (1);
+    }
+
+  h = dlopen ("tst-tlsmod15b.so", RTLD_NOW);
+  if (h == NULL)
+    {
+      puts ("failed to open tst-tlsmod15b.so");
+      exit (1);
+    }
+
+  int (*fp) (void) = (int (*) (void)) dlsym (h, "in_dso");
+  if (fp == NULL)
+    {
+      puts ("cannot find in_dso");
+      exit (1);
+    }
+
+  return fp ();
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"
--- libc/elf/tst-tlsmod15a.c.jj	2005-03-15 15:13:26.850098066 +0100
+++ libc/elf/tst-tlsmod15a.c	2005-03-15 15:13:22.082947275 +0100
@@ -0,0 +1,6 @@
+extern int nonexistent_dummy_var;
+int *
+foo (void)
+{
+  return &nonexistent_dummy_var;
+}
--- libc/elf/tst-tlsmod15b.c.jj	2005-03-15 15:13:54.578158642 +0100
+++ libc/elf/tst-tlsmod15b.c	2005-03-15 15:15:38.723606220 +0100
@@ -0,0 +1,17 @@
+#include "tst-tls10.h"
+
+#ifdef USE_TLS__THREAD
+__thread int mod15b_var __attribute__((tls_model("initial-exec")));
+
+int
+in_dso (void)
+{
+  return mod15b_var;
+}
+#else
+int
+in_dso (void)
+{
+  return 0;
+}
+#endif


	Jakub