From: Florian Weimer <fweimer@redhat.com>
Date: Thu, 4 Feb 2021 14:00:20 +0000 (+0100)
Subject: nptl: Remove private futex optimization [BZ #27304]
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=79c6be6a0ad59e28cfb73ad6cae6b073e22836e3;p=thirdparty%2Fglibc.git

nptl: Remove private futex optimization [BZ #27304]

It is effectively used, unexcept for pthread_cond_destroy, where we do
not want it; see bug 27304.  The internal locks do not support a
process-shared mode.

This fixes commit dc6cfdc934db9997c33728082d63552b9eee4563 ("nptl:
Move pthread_cond_destroy implementation into libc").

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
(cherry picked from commit c4ad832276f4dadfa40904109b26a521468f66bc)
---

diff --git a/NEWS b/NEWS
index 94466f43a5b..62612237f84 100644
--- a/NEWS
+++ b/NEWS
@@ -18,6 +18,7 @@ The following bugs are resolved with this release:
   [18435] pthread_once hangs when init routine throws an exception
   [23462] Static binary with dynamic string tokens ($LIB, $PLATFORM, $ORIGIN)
     crashes
+  [27304] pthread_cond_destroy does not pass private flag to futex system calls
   [27577] elf/ld.so --help doesn't work
 
 Version 2.33
diff --git a/sysdeps/nptl/lowlevellock-futex.h b/sysdeps/nptl/lowlevellock-futex.h
index ecb729da6b8..ca96397a4a9 100644
--- a/sysdeps/nptl/lowlevellock-futex.h
+++ b/sysdeps/nptl/lowlevellock-futex.h
@@ -50,20 +50,8 @@
 #define LLL_SHARED	FUTEX_PRIVATE_FLAG
 
 #ifndef __ASSEMBLER__
-
-# if IS_IN (libc) || IS_IN (rtld)
-/* In libc.so or ld.so all futexes are private.  */
-#  define __lll_private_flag(fl, private)			\
-  ({								\
-    /* Prevent warnings in callers of this macro.  */		\
-    int __lll_private_flag_priv __attribute__ ((unused));	\
-    __lll_private_flag_priv = (private);			\
-    ((fl) | FUTEX_PRIVATE_FLAG);				\
-  })
-# else
-#  define __lll_private_flag(fl, private) \
+# define __lll_private_flag(fl, private) \
   (((fl) | FUTEX_PRIVATE_FLAG) ^ (private))
-# endif
 
 # define lll_futex_syscall(nargs, futexp, op, ...)                      \
   ({                                                                    \