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Re: [PING 2][PATCH v8] Fix dynamic linker issue with bind-now


On Tue, Aug 18, 2015 at 12:48 PM, Petar Jovanovic
<petar.jovanovic@rt-rk.com> wrote:
> -----Original Message-----
> From: H.J. Lu [mailto:hjl.tools@gmail.com]
> Sent: Tuesday, August 18, 2015 8:55 PM
> To: Petar Jovanovic <petar.jovanovic@rt-rk.com>
> Cc: GNU C Library <libc-alpha@sourceware.org>; Roland McGrath <roland@hack.frob.com>; Andreas Schwab <schwab@linux-m68k.org>; Mike Frysinger <vapier@gentoo.org>
> Subject: Re: [PING 2][PATCH v8] Fix dynamic linker issue with bind-now
>> Please provide a patch from "git format-patch with proper ChangeLog entry.
>> --
>> H.J.
>
> Hi H.J.,
>
> Have not I already provided this at the start [1] of this thread?
> Is there anything that should be modified here?
>
> Let me know.
>
> Regards,
> Petar
>
> [1] patch v8, https://sourceware.org/ml/libc-alpha/2015-07/msg00489.html
>

I moved testcase to sysdep/x86_64 and tested it on x86/x86-64.
This is what I checked in for you.

Thanks.

-- 
H.J.
From fa19d5c48a6b36518ce68412e3bdde6bfa8aa4a6 Mon Sep 17 00:00:00 2001
From: Petar Jovanovic <petar.jovanovic@rt-rk.com>
Date: Wed, 20 Aug 2014 00:50:54 +0200
Subject: [PATCH] Fix dynamic linker issue with bind-now

Fix the bind-now case when DT_REL and DT_JMPREL sections are separate
and there is a gap between them.

	[BZ #14341]
	* elf/dynamic-link.h (elf_machine_lazy_rel): Properly handle the
	case when there is a gap between DT_REL and DT_JMPREL sections.
	* sysdeps/x86_64/Makefile (tests): Add tst-split-dynreloc.
	(LDFLAGS-tst-split-dynreloc): New.
	(tst-split-dynreloc-ENV): Likewise.
	* sysdeps/x86_64/tst-split-dynreloc.c: New file.
	* sysdeps/x86_64/tst-split-dynreloc.lds: Likewise.
---
 ChangeLog                             | 11 +++++++++++
 elf/dynamic-link.h                    | 14 ++++++++------
 sysdeps/x86_64/Makefile               |  5 +++++
 sysdeps/x86_64/tst-split-dynreloc.c   | 28 ++++++++++++++++++++++++++++
 sysdeps/x86_64/tst-split-dynreloc.lds |  5 +++++
 5 files changed, 57 insertions(+), 6 deletions(-)
 create mode 100644 sysdeps/x86_64/tst-split-dynreloc.c
 create mode 100644 sysdeps/x86_64/tst-split-dynreloc.lds

diff --git a/ChangeLog b/ChangeLog
index 83fef46..4218f2c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2015-08-19   Petar Jovanovic  <petar.jovanovic@rt-rk.com>
+
+	[BZ #14341]
+	* elf/dynamic-link.h (elf_machine_lazy_rel): Properly handle the
+	case when there is a gap between DT_REL and DT_JMPREL sections.
+	* sysdeps/x86_64/Makefile (tests): Add tst-split-dynreloc.
+	(LDFLAGS-tst-split-dynreloc): New.
+	(tst-split-dynreloc-ENV): Likewise.
+	* sysdeps/x86_64/tst-split-dynreloc.c: New file.
+	* sysdeps/x86_64/tst-split-dynreloc.lds: Likewise.
+
 2015-08-19  H.J. Lu  <hongjiu.lu@intel.com>
 
 	[BZ #18822]
diff --git a/elf/dynamic-link.h b/elf/dynamic-link.h
index 8d428e2..d7cff48 100644
--- a/elf/dynamic-link.h
+++ b/elf/dynamic-link.h
@@ -135,16 +135,18 @@ elf_machine_lazy_rel (struct link_map *map,
 									      \
 	if (ranges[0].start + ranges[0].size == (start + size))		      \
 	  ranges[0].size -= size;					      \
-	if (! ELF_DURING_STARTUP && ((do_lazy) || ranges[0].size == 0))	      \
+	if (ELF_DURING_STARTUP						      \
+	    || (!(do_lazy)						      \
+		&& (ranges[0].start + ranges[0].size) == start))	      \
 	  {								      \
-	    ranges[1].start = start;					      \
-	    ranges[1].size = size;					      \
-	    ranges[1].lazy = (do_lazy);					      \
+	    /* Combine processing the sections.  */			      \
+	    ranges[0].size += size;					      \
 	  }								      \
 	else								      \
 	  {								      \
-	    /* Combine processing the sections.  */			      \
-	    ranges[0].size += size;					      \
+	    ranges[1].start = start;					      \
+	    ranges[1].size = size;					      \
+	    ranges[1].lazy = (do_lazy);					      \
 	  }								      \
       }									      \
 									      \
diff --git a/sysdeps/x86_64/Makefile b/sysdeps/x86_64/Makefile
index ef70a50..91875f0 100644
--- a/sysdeps/x86_64/Makefile
+++ b/sysdeps/x86_64/Makefile
@@ -38,6 +38,11 @@ tests += tst-audit3 tst-audit4 tst-audit5 tst-audit10
 ifeq (yes,$(config-cflags-avx))
 tests += tst-audit6 tst-audit7
 endif
+
+tests += tst-split-dynreloc
+LDFLAGS-tst-split-dynreloc = -Wl,-T,$(..)sysdeps/x86_64/tst-split-dynreloc.lds
+tst-split-dynreloc-ENV = LD_BIND_NOW=1
+
 modules-names += tst-auditmod3a tst-auditmod3b \
 		tst-auditmod4a tst-auditmod4b \
 		tst-auditmod5a tst-auditmod5b \
diff --git a/sysdeps/x86_64/tst-split-dynreloc.c b/sysdeps/x86_64/tst-split-dynreloc.c
new file mode 100644
index 0000000..2f9e9b9
--- /dev/null
+++ b/sysdeps/x86_64/tst-split-dynreloc.c
@@ -0,0 +1,28 @@
+/* This test will be used to create an executable with a specific
+   section layout in which .rela.dyn and .rela.plt are not contiguous.
+   For x86 case, readelf will report something like:
+
+   ...
+   [10] .rela.dyn         RELA
+   [11] .bar              PROGBITS
+   [12] .rela.plt         RELA
+   ...
+
+   This is important as this case was not correctly handled by dynamic
+   linker in the bind-now case, and the second section was never
+   processed.  */
+
+#include <stdio.h>
+
+const int __attribute__ ((section(".bar"))) bar = 0x12345678;
+static const char foo[] = "foo";
+
+static int
+do_test (void)
+{
+  printf ("%s %d\n", foo, bar);
+  return 0;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"
diff --git a/sysdeps/x86_64/tst-split-dynreloc.lds b/sysdeps/x86_64/tst-split-dynreloc.lds
new file mode 100644
index 0000000..2229e69
--- /dev/null
+++ b/sysdeps/x86_64/tst-split-dynreloc.lds
@@ -0,0 +1,5 @@
+SECTIONS
+{
+   .bar : { *(.bar) }
+}
+INSERT AFTER .rela.dyn;
-- 
2.4.3


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