Avoid .symver on common symbols [BZ #21666]

The .symver directive on common symbol just creates a new common symbol,
not an alias and the newer assembler with the bug fix for

https://sourceware.org/bugzilla/show_bug.cgi?id=21661

will issue an error.  Before the fix, we got

$ readelf -sW libc.so | grep "loc[12s]"
  5109: 00000000003a0608     8 OBJECT  LOCAL  DEFAULT   36 loc1
  5188: 00000000003a0610     8 OBJECT  LOCAL  DEFAULT   36 loc2
  5455: 00000000003a0618     8 OBJECT  LOCAL  DEFAULT   36 locs
  6575: 00000000003a05f0     8 OBJECT  GLOBAL DEFAULT   36 locs@GLIBC_2.2.5
  7156: 00000000003a05f8     8 OBJECT  GLOBAL DEFAULT   36 loc1@GLIBC_2.2.5
  7312: 00000000003a0600     8 OBJECT  GLOBAL DEFAULT   36 loc2@GLIBC_2.2.5

in libc.so.  The versioned loc1, loc2 and locs have the wrong addresses.
After the fix, we got

$ readelf -sW libc.so | grep "loc[12s]"
  6570: 000000000039e3b8     8 OBJECT  GLOBAL DEFAULT   34 locs@GLIBC_2.2.5
  7151: 000000000039e3c8     8 OBJECT  GLOBAL DEFAULT   34 loc1@GLIBC_2.2.5
  7307: 000000000039e3c0     8 OBJECT  GLOBAL DEFAULT   34 loc2@GLIBC_2.2.5

	[BZ #21666]
	* misc/regexp.c (loc1): Add __attribute__ ((nocommon));
	(loc2): Likewise.
	(locs): Likewise.

(cherry picked from commit 388b4f1a02f3a801965028bbfcd48d905638b797)

diff --git a/ChangeLog b/ChangeLog
index 2f8f9c606b27985800fdcf8ff5aed744703c5c75..178ffca243b95fe6fc970a487728c333abed9c07 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2017-07-26  H.J. Lu  <hongjiu.lu@intel.com>
+
+       [BZ #21666]
+       * misc/regexp.c (loc1): Add __attribute__ ((nocommon));
+       (loc2): Likewise.
+       (locs): Likewise.
+
 2017-07-12  Szabolcs Nagy  <szabolcs.nagy@arm.com>
 
        * sysdeps/aarch64/dl-machine.h (RTLD_START_1): Change _dl_argv to the

diff --git a/misc/regexp.c b/misc/regexp.c
index 3b3668272f4e8c3a8fb4393f15268da298245843..b2a2c6e6364c7a85cf1dd74a48d6fc23ad167c24 100644 (file)
--- a/misc/regexp.c
+++ b/misc/regexp.c
@@ -29,14 +29,15 @@
 
 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_23)
 
-/* Define the variables used for the interface.  */
-char *loc1;
-char *loc2;
+/* Define the variables used for the interface.  Avoid .symver on common
+   symbol, which just creates a new common symbol, not an alias.  */
+char *loc1 __attribute__ ((nocommon));
+char *loc2 __attribute__ ((nocommon));
 compat_symbol (libc, loc1, loc1, GLIBC_2_0);
 compat_symbol (libc, loc2, loc2, GLIBC_2_0);
 
 /* Although we do not support the use we define this variable as well.  */
-char *locs;
+char *locs __attribute__ ((nocommon));
 compat_symbol (libc, locs, locs, GLIBC_2_0);