musl: fix failure to obtain EOWNERDEAD status for process-shared robust mutexes

Added upstream patch:

Linux's documentation (robust-futex-ABI.txt) claims that, when a
process dies with a futex on the robust list, bit 30 (0x40000000) is
set to indicate the status. however, what actually happens is that
bits 0-30 are replaced with the value 0x40000000, i.e. bits 0-29
(containing the old owner tid) are cleared at the same time bit 30 is
set.

our userspace-side code for robust mutexes was written based on that
documentation, assuming that kernel would never produce a futex value
of 0x40000000, since the low (owner) bits would always be non-zero.
commit d338b506e39b1e2c68366b12be90704c635602ce introduced this
assumption explicitly while fixing another bug in how non-recoverable
status for robust mutexes was tracked. presumably the tests conducted
at that time only checked non-process-shared robust mutexes, which are
handled in pthread_exit (which implemented the documented kernel
protocol, not the actual one) rather than by the kernel.

change pthread_exit robust list processing to match the kernel
behavior, clearing bits 0-29 while setting bit 30, and use the value
0x7fffffff instead of 0x40000000 to encode non-recoverable status. the
choice of value here is arbitrary; any value with at least one of bits
0-29 set should work just as well,

fixes #4392

srcpkgs/musl-bootstrap/template

@@ -1,7 +1,7 @@
 # Template file for 'musl-bootstrap'.
 pkgname=musl-bootstrap
 version=1.1.14
-revision=3
+revision=4
 lib32disabled=yes
 wrksrc="musl-${version}"
 build_style=configure

srcpkgs/musl/patches/fix-failure-to-obtain-EOWNERDEAD-status-for-process-shared-robust-mutexes.patch

@@ -0,0 +1,76 @@
+From 384d103d94dba0472a587861f67d7ed6e8955f86 Mon Sep 17 00:00:00 2001
+From: Rich Felker <dalias@aerifal.cx>
+Date: Mon, 27 Jun 2016 15:18:13 -0400
+Subject: fix failure to obtain EOWNERDEAD status for process-shared robust
+ mutexes
+
+Linux's documentation (robust-futex-ABI.txt) claims that, when a
+process dies with a futex on the robust list, bit 30 (0x40000000) is
+set to indicate the status. however, what actually happens is that
+bits 0-30 are replaced with the value 0x40000000, i.e. bits 0-29
+(containing the old owner tid) are cleared at the same time bit 30 is
+set.
+
+our userspace-side code for robust mutexes was written based on that
+documentation, assuming that kernel would never produce a futex value
+of 0x40000000, since the low (owner) bits would always be non-zero.
+commit d338b506e39b1e2c68366b12be90704c635602ce introduced this
+assumption explicitly while fixing another bug in how non-recoverable
+status for robust mutexes was tracked. presumably the tests conducted
+at that time only checked non-process-shared robust mutexes, which are
+handled in pthread_exit (which implemented the documented kernel
+protocol, not the actual one) rather than by the kernel.
+
+change pthread_exit robust list processing to match the kernel
+behavior, clearing bits 0-29 while setting bit 30, and use the value
+0x7fffffff instead of 0x40000000 to encode non-recoverable status. the
+choice of value here is arbitrary; any value with at least one of bits
+0-29 set should work just as well,
+---
+ src/thread/pthread_create.c        | 2 +-
+ src/thread/pthread_mutex_trylock.c | 2 +-
+ src/thread/pthread_mutex_unlock.c  | 2 +-
+ 3 files changed, 3 insertions(+), 3 deletions(-)
+
+diff --git src/thread/pthread_create.c src/thread/pthread_create.c
+index e7df34a..9f6b98e 100644
+--- src/thread/pthread_create.c
++++ src/thread/pthread_create.c
+@@ -79,7 +79,7 @@ _Noreturn void __pthread_exit(void *result)
+ 		int priv = (m->_m_type & 128) ^ 128;
+ 		self->robust_list.pending = rp;
+ 		self->robust_list.head = *rp;
+-		int cont = a_swap(&m->_m_lock, self->tid|0x40000000);
++		int cont = a_swap(&m->_m_lock, 0x40000000);
+ 		self->robust_list.pending = 0;
+ 		if (cont < 0 || waiters)
+ 			__wake(&m->_m_lock, 1, priv);
+diff --git src/thread/pthread_mutex_trylock.c src/thread/pthread_mutex_trylock.c
+index 0df3ce2..54876a6 100644
+--- src/thread/pthread_mutex_trylock.c
++++ src/thread/pthread_mutex_trylock.c
+@@ -14,7 +14,7 @@ int __pthread_mutex_trylock_owner(pthread_mutex_t *m)
+ 		m->_m_count++;
+ 		return 0;
+ 	}
+-	if (own == 0x40000000) return ENOTRECOVERABLE;
++	if (own == 0x7fffffff) return ENOTRECOVERABLE;
+ 
+ 	if (m->_m_type & 128) {
+ 		if (!self->robust_list.off) {
+diff --git src/thread/pthread_mutex_unlock.c src/thread/pthread_mutex_unlock.c
+index 02da92a..7dd00d2 100644
+--- src/thread/pthread_mutex_unlock.c
++++ src/thread/pthread_mutex_unlock.c
+@@ -24,7 +24,7 @@ int __pthread_mutex_unlock(pthread_mutex_t *m)
+ 		if (next != &self->robust_list.head) *(volatile void *volatile *)
+ 			((char *)next - sizeof(void *)) = prev;
+ 	}
+-	cont = a_swap(&m->_m_lock, (type & 8) ? 0x40000000 : 0);
++	cont = a_swap(&m->_m_lock, (type & 8) ? 0x7fffffff : 0);
+ 	if (type != PTHREAD_MUTEX_NORMAL && !priv) {
+ 		self->robust_list.pending = 0;
+ 		__vm_unlock();
+-- 
+cgit v0.11.2
+

srcpkgs/musl/template

@@ -1,7 +1,7 @@
 # Template file for 'musl'.
 pkgname=musl
 version=1.1.14
-revision=1
+revision=2
 build_style=gnu-configure
 configure_args="--prefix=/usr --disable-gcc-wrapper"
 conflicts="glibc>=0"