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Torvald Riegel 65810f0ef0 robust mutexes: Fix broken x86 assembly by removing it
lll_robust_unlock on i386 and x86_64 first sets the futex word to
FUTEX_WAITERS|0 before calling __lll_unlock_wake, which will set the
futex word to 0.  If the thread is killed between these steps, then the
futex word will be FUTEX_WAITERS|0, and the kernel (at least current
upstream) will not set it to FUTEX_OWNER_DIED|FUTEX_WAITERS because 0 is
not equal to the TID of the crashed thread.

The lll_robust_lock assembly code on i386 and x86_64 is not prepared to
deal with this case because the fastpath tries to only CAS 0 to TID and
not FUTEX_WAITERS|0 to TID; the slowpath simply waits until it can CAS 0
to TID or the futex_word has the FUTEX_OWNER_DIED bit set.

This issue is fixed by removing the custom x86 assembly code and using
the generic C code instead.  However, instead of adding more duplicate
code to the custom x86 lowlevellock.h, the code of the lll_robust* functions
is inlined into the single call sites that exist for each of these functions
in the pthread_mutex_* functions.  The robust mutex paths in the latter
have been slightly reorganized to make them simpler.

This patch is meant to be easy to backport, so C11-style atomics are not
used.

	[BZ #20985]
	* nptl/Makefile: Adapt.
	* nptl/pthread_mutex_cond_lock.c (LLL_ROBUST_MUTEX_LOCK): Remove.
	(LLL_ROBUST_MUTEX_LOCK_MODIFIER): New.
	* nptl/pthread_mutex_lock.c (LLL_ROBUST_MUTEX_LOCK): Remove.
	(LLL_ROBUST_MUTEX_LOCK_MODIFIER): New.
	(__pthread_mutex_lock_full): Inline lll_robust* functions and adapt.
	* nptl/pthread_mutex_timedlock.c (pthread_mutex_timedlock): Inline
	lll_robust* functions and adapt.
	* nptl/pthread_mutex_unlock.c (__pthread_mutex_unlock_full): Likewise.
	* sysdeps/nptl/lowlevellock.h (__lll_robust_lock_wait,
	__lll_robust_lock, lll_robust_cond_lock, __lll_robust_timedlock_wait,
	__lll_robust_timedlock, __lll_robust_unlock): Remove.
	* sysdeps/unix/sysv/linux/i386/lowlevellock.h (lll_robust_lock,
	lll_robust_cond_lock, lll_robust_timedlock, lll_robust_unlock): Remove.
	* sysdeps/unix/sysv/linux/x86_64/lowlevellock.h (lll_robust_lock,
	lll_robust_cond_lock, lll_robust_timedlock, lll_robust_unlock): Remove.
	* sysdeps/unix/sysv/linux/sparc/lowlevellock.h (__lll_robust_lock_wait,
	__lll_robust_lock, lll_robust_cond_lock, __lll_robust_timedlock_wait,
	__lll_robust_timedlock, __lll_robust_unlock): Remove.
	* nptl/lowlevelrobustlock.c: Remove file.
	* nptl/lowlevelrobustlock.sym: Likewise.
	* sysdeps/unix/sysv/linux/i386/lowlevelrobustlock.S: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/lowlevelrobustlock.S: Likewise.
2017-01-13 17:16:07 +01:00
argp Update copyright dates with scripts/update-copyrights. 2017-01-01 00:14:16 +00:00
assert Update copyright dates with scripts/update-copyrights. 2017-01-01 00:14:16 +00:00
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bits Make endian-conversion macros always return correct types (bug 16458). 2017-01-11 15:28:08 +00:00
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elf Fix elf/sotruss-lib format-truncation error. 2017-01-11 13:57:59 +00:00
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iconvdata Increase some test timeouts. 2017-01-05 17:39:38 +00:00
include Use fortify macros for b{zero,copy} along decl from strings.h 2017-01-05 15:54:13 -02:00
inet Make endian-conversion macros always return correct types (bug 16458). 2017-01-11 15:28:08 +00:00
intl Update copyright dates with scripts/update-copyrights. 2017-01-01 00:14:16 +00:00
io Fix MIPS n32 lseek, lseek64 (bug 21019). 2017-01-02 23:09:25 +00:00
libidn Update copyright dates with scripts/update-copyrights. 2017-01-01 00:14:16 +00:00
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malloc Increase some test timeouts. 2017-01-05 17:39:38 +00:00
manual Update copyright dates not handled by scripts/update-copyrights. 2017-01-01 00:26:24 +00:00
math Make fallback fegetexceptflag work with generic fetestexceptflag. 2017-01-12 01:52:37 +00:00
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nptl robust mutexes: Fix broken x86 assembly by removing it 2017-01-13 17:16:07 +01:00
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scripts Make build-many-glibcs.py work on python3.2 2017-01-11 10:30:40 -02:00
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stdio-common Fix testsuite build for GCC 7 -Wformat-truncation. 2017-01-11 14:02:23 +00:00
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string Make endian-conversion macros always return correct types (bug 16458). 2017-01-11 15:28:08 +00:00
sunrpc Update copyright dates with scripts/update-copyrights. 2017-01-01 00:14:16 +00:00
support support: struct netent portability fix for support_format_netent 2017-01-01 09:35:45 +01:00
sysdeps robust mutexes: Fix broken x86 assembly by removing it 2017-01-13 17:16:07 +01:00
sysvipc Fix test-sysvsem on some platforms 2017-01-02 18:53:50 -02:00
termios Update copyright dates with scripts/update-copyrights. 2017-01-01 00:14:16 +00:00
time Fix testsuite build for GCC 7 -Wformat-truncation. 2017-01-11 14:02:23 +00:00
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wcsmbs Fix testsuite build for GCC 7 -Wformat-truncation. 2017-01-11 14:02:23 +00:00
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.gitattributes Assume __NR_openat is always defined 2016-03-23 23:35:08 +01:00
.gitignore
abi-tags
aclocal.m4 Work even with compilers which enable -fstack-protector by default [BZ #7065] 2016-12-26 10:10:58 +01:00
BUGS
ChangeLog robust mutexes: Fix broken x86 assembly by removing it 2017-01-13 17:16:07 +01:00
ChangeLog.1
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ChangeLog.8 ChangeLog: change Winblowz to Windows 2016-08-10 00:49:28 +08:00
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ChangeLog.11 ChangeLog: change Winblowz to Windows 2016-08-10 00:49:28 +08:00
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ChangeLog.old-ports-tile
config.h.in Add framework for tunables 2016-12-31 23:49:24 +05:30
config.make.in Initialize tunable list with the GLIBC_TUNABLES environment variable 2016-12-31 23:49:24 +05:30
configure Enhance --enable-tunables to select tunables frontend at build time 2016-12-31 23:49:24 +05:30
configure.ac Enhance --enable-tunables to select tunables frontend at build time 2016-12-31 23:49:24 +05:30
CONFORMANCE
COPYING
COPYING.LIB
cppflags-iterator.mk
extra-lib.mk support: Introduce new subdirectory for test infrastructure 2016-12-09 08:18:27 +01:00
extra-modules.mk
gen-locales.mk
INSTALL Enhance --enable-tunables to select tunables frontend at build time 2016-12-31 23:49:24 +05:30
libc-abis
LICENSES
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Makefile.in New make target to only build benchmark binaries 2016-04-20 10:23:28 +05:30
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NAMESPACE
NEWS Update copyright dates not handled by scripts/update-copyrights. 2017-01-01 00:26:24 +00:00
o-iterator.mk
README Require Linux 3.2 except on x86 / x86_64, 3.2 headers everywhere. 2016-02-24 17:15:12 +00:00
README.pretty-printers Fix failing pretty printer tests when CPPFLAGS has optimizations. 2016-12-23 13:46:56 -05:00
README.tunables Add framework for tunables 2016-12-31 23:49:24 +05:30
Rules Update copyright dates with scripts/update-copyrights. 2017-01-01 00:14:16 +00:00
shlib-versions
test-skeleton.c Update copyright dates with scripts/update-copyrights. 2017-01-01 00:14:16 +00:00
version.h Open development for 2.25. 2016-08-01 23:00:21 -04:00
WUR-REPORT

This directory contains the sources of the GNU C Library.
See the file "version.h" for what release version you have.

The GNU C Library is the standard system C library for all GNU systems,
and is an important part of what makes up a GNU system.  It provides the
system API for all programs written in C and C-compatible languages such
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The GNU C Library implements much of the POSIX.1 functionality in the
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When working with Linux kernels, this version of the GNU C Library
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