[packages/glibc.git] / glibc-rh-bug-769421.patch

http://sourceware.org/ml/libc-alpha/2012-01/msg00002.html

The following patch:
Has been reported as causing numerous problems in Fedora & Debian.  I
don't think anyone has done any serious analysis of the issue, but the
patch has been pulled from both distributions because of the
instability it's introduced.

https://bugzilla.redhat.com/show_bug.cgi?id=769421
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=651899


commit c5a0802a682dba23f92d47f0f99775aebfbe2539
Author: Andreas Schwab <schwab@redhat.com>
Date:   Mon Nov 28 13:38:19 2011 +0100

    Handle EAGAIN from FUTEX_WAIT_REQUEUE_PI

2011-11-28  Andreas Schwab  <schwab@redhat.com>

	* sysdeps/unix/sysv/linux/i386/i486/pthread_cond_wait.S: Handle
	EAGAIN from FUTEX_WAIT_REQUEUE_PI.
	* sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S: Likewise.

diff --git a/nptl/sysdeps/unix/sysv/linux/i386/i486/pthread_cond_wait.S b/nptl/sysdeps/unix/sysv/linux/i386/i486/pthread_cond_wait.S
index 54590b7..53970d7 100644
--- a/nptl/sysdeps/unix/sysv/linux/i386/i486/pthread_cond_wait.S
+++ b/nptl/sysdeps/unix/sysv/linux/i386/i486/pthread_cond_wait.S
@@ -134,7 +134,6 @@ __pthread_cond_wait:
 	cmpl	$PI_BIT, %eax
 	jne	18f
 
-90:
 	movl	$(FUTEX_WAIT_REQUEUE_PI|FUTEX_PRIVATE_FLAG), %ecx
 	movl	%ebp, %edx
 	xorl	%esi, %esi
@@ -148,9 +147,6 @@ __pthread_cond_wait:
 	sete	16(%esp)
 	je	19f
 
-	cmpl	$-EAGAIN, %eax
-	je	91f
-
 	/* Normal and PI futexes dont mix. Use normal futex functions only
 	   if the kernel does not support the PI futex functions.  */
 	cmpl	$-ENOSYS, %eax
@@ -395,78 +391,6 @@ __pthread_cond_wait:
 #endif
 	call	__lll_unlock_wake
 	jmp	11b
-
-91:
-.LcleanupSTART2:
-	/* FUTEX_WAIT_REQUEUE_PI returned EAGAIN.  We need to
-	   call it again.  */
-
-	/* Get internal lock.  */
-	movl	$1, %edx
-	xorl	%eax, %eax
-	LOCK
-#if cond_lock == 0
-	cmpxchgl %edx, (%ebx)
-#else
-	cmpxchgl %edx, cond_lock(%ebx)
-#endif
-	jz	92f
-
-#if cond_lock == 0
-	movl	%ebx, %edx
-#else
-	leal	cond_lock(%ebx), %edx
-#endif
-#if (LLL_SHARED-LLL_PRIVATE) > 255
-	xorl	%ecx, %ecx
-#endif
-	cmpl	$-1, dep_mutex(%ebx)
-	setne	%cl
-	subl	$1, %ecx
-	andl	$(LLL_SHARED-LLL_PRIVATE), %ecx
-#if LLL_PRIVATE != 0
-	addl	$LLL_PRIVATE, %ecx
-#endif
-	call	__lll_lock_wait
-
-92:
-	/* Increment the cond_futex value again, so it can be used as a new
-	   expected value. */
-	addl	$1, cond_futex(%ebx)
-	movl	cond_futex(%ebx), %ebp
-
-	/* Unlock.  */
-	LOCK
-#if cond_lock == 0
-	subl	$1, (%ebx)
-#else
-	subl	$1, cond_lock(%ebx)
-#endif
-	je	93f
-#if cond_lock == 0
-	movl	%ebx, %eax
-#else
-	leal	cond_lock(%ebx), %eax
-#endif
-#if (LLL_SHARED-LLL_PRIVATE) > 255
-	xorl	%ecx, %ecx
-#endif
-	cmpl	$-1, dep_mutex(%ebx)
-	setne	%cl
-	subl	$1, %ecx
-	andl	$(LLL_SHARED-LLL_PRIVATE), %ecx
-#if LLL_PRIVATE != 0
-	addl	$LLL_PRIVATE, %ecx
-#endif
-	call	__lll_unlock_wake
-
-93:
-	/* Set the rest of SYS_futex args for FUTEX_WAIT_REQUEUE_PI. */
-	xorl	%ecx, %ecx
-	movl	dep_mutex(%ebx), %edi
-	jmp	90b
-.LcleanupEND2:
-
 	.size	__pthread_cond_wait, .-__pthread_cond_wait
 versioned_symbol (libpthread, __pthread_cond_wait, pthread_cond_wait,
 		  GLIBC_2_3_2)
@@ -639,10 +563,6 @@ __condvar_w_cleanup:
 	.long	.LcleanupEND-.Lsub_cond_futex
 	.long	__condvar_w_cleanup-.LSTARTCODE
 	.uleb128  0
-	.long	.LcleanupSTART2-.LSTARTCODE
-	.long	.LcleanupEND2-.LcleanupSTART2
-	.long	__condvar_w_cleanup-.LSTARTCODE
-	.uleb128  0
 	.long	.LcallUR-.LSTARTCODE
 	.long	.LENDCODE-.LcallUR
 	.long	0
diff --git a/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S b/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S
index d837d15..7535baa 100644
--- a/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S
+++ b/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S
@@ -23,7 +23,6 @@
 #include <lowlevelcond.h>
 #include <tcb-offsets.h>
 #include <pthread-pi-defines.h>
-#include <pthread-errnos.h>
 #include <stap-probe.h>
 
 #include <kernel-features.h>
@@ -134,14 +133,11 @@ __pthread_cond_wait:
 	cmpl	$PI_BIT, %eax
 	jne	61f
 
-90:
 	movl	$(FUTEX_WAIT_REQUEUE_PI|FUTEX_PRIVATE_FLAG), %esi
 	movl	$SYS_futex, %eax
 	syscall
 
 	movl	$1, %r8d
-	cmpq	$-EAGAIN, %rax
-	je	91f
 #ifdef __ASSUME_REQUEUE_PI
 	jmp	62f
 #else
@@ -328,70 +324,6 @@ __pthread_cond_wait:
 
 13:	movq	%r10, %rax
 	jmp	14b
-
-91:
-.LcleanupSTART2:
-	/* FUTEX_WAIT_REQUEUE_PI returned EAGAIN.  We need to
-	   call it again.  */
-	movq	8(%rsp), %rdi
-
-	/* Get internal lock.  */
-	movl	$1, %esi
-	xorl	%eax, %eax
-	LOCK
-#if cond_lock == 0
-	cmpxchgl %esi, (%rdi)
-#else
-	cmpxchgl %esi, cond_lock(%rdi)
-#endif
-	jz	92f
-
-#if cond_lock != 0
-	addq	$cond_lock, %rdi
-#endif
-	LP_OP(cmp) $-1, dep_mutex-cond_lock(%rdi)
-	movl	$LLL_PRIVATE, %eax
-	movl	$LLL_SHARED, %esi
-	cmovne	%eax, %esi
-	callq	__lll_lock_wait
-#if cond_lock != 0
-	subq	$cond_lock, %rdi
-#endif
-92:
-	/* Increment the cond_futex value again, so it can be used as a new
-	   expected value. */
-	incl	cond_futex(%rdi)
-	movl	cond_futex(%rdi), %edx
-
-	/* Release internal lock.  */
-	LOCK
-#if cond_lock == 0
-	decl	(%rdi)
-#else
-	decl	cond_lock(%rdi)
-#endif
-	jz	93f
-
-#if cond_lock != 0
-	addq	$cond_lock, %rdi
-#endif
-	LP_OP(cmp) $-1, dep_mutex-cond_lock(%rdi)
-	movl	$LLL_PRIVATE, %eax
-	movl	$LLL_SHARED, %esi
-	cmovne	%eax, %esi
-	/* The call preserves %rdx.  */
-	callq	__lll_unlock_wake
-#if cond_lock != 0
-	subq	$cond_lock, %rdi
-#endif
-93:
-	/* Set the rest of SYS_futex args for FUTEX_WAIT_REQUEUE_PI. */
-	xorq	%r10, %r10
-	mov	dep_mutex(%rdi), %R8_LP
-	leaq	cond_futex(%rdi), %rdi
-	jmp	90b
-.LcleanupEND2:
-
 	.size	__pthread_cond_wait, .-__pthread_cond_wait
 versioned_symbol (libpthread, __pthread_cond_wait, pthread_cond_wait,
 		  GLIBC_2_3_2)
@@ -544,15 +476,11 @@ __condvar_cleanup1:
 	.uleb128 .LcleanupSTART-.LSTARTCODE
 	.uleb128 .LcleanupEND-.LcleanupSTART
 	.uleb128 __condvar_cleanup1-.LSTARTCODE
-	.uleb128 0
-	.uleb128 .LcleanupSTART2-.LSTARTCODE
-	.uleb128 .LcleanupEND2-.LcleanupSTART2
-	.uleb128 __condvar_cleanup1-.LSTARTCODE
-	.uleb128 0
+	.uleb128  0
 	.uleb128 .LcallUR-.LSTARTCODE
 	.uleb128 .LENDCODE-.LcallUR
 	.uleb128 0
-	.uleb128 0
+	.uleb128  0
 .Lcstend:
Commit	Line	Data
0f2e926c AM	1	http://sourceware.org/ml/libc-alpha/2012-01/msg00002.html
	2
	3	The following patch:
	4	Has been reported as causing numerous problems in Fedora & Debian. I
	5	don't think anyone has done any serious analysis of the issue, but the
	6	patch has been pulled from both distributions because of the
	7	instability it's introduced.
	8
	9	https://bugzilla.redhat.com/show_bug.cgi?id=769421
	10	http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=651899
	11
	12
	13	commit c5a0802a682dba23f92d47f0f99775aebfbe2539
	14	Author: Andreas Schwab <schwab@redhat.com>
	15	Date: Mon Nov 28 13:38:19 2011 +0100
	16
	17	Handle EAGAIN from FUTEX_WAIT_REQUEUE_PI
	18
	19	2011-11-28 Andreas Schwab <schwab@redhat.com>
	20
	21	* sysdeps/unix/sysv/linux/i386/i486/pthread_cond_wait.S: Handle
	22	EAGAIN from FUTEX_WAIT_REQUEUE_PI.
	23	* sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S: Likewise.
	24
	25	diff --git a/nptl/sysdeps/unix/sysv/linux/i386/i486/pthread_cond_wait.S b/nptl/sysdeps/unix/sysv/linux/i386/i486/pthread_cond_wait.S
583469ac	26	index 54590b7..53970d7 100644
0f2e926c AM	27	--- a/nptl/sysdeps/unix/sysv/linux/i386/i486/pthread_cond_wait.S
0f2e926c AM	28	+++ b/nptl/sysdeps/unix/sysv/linux/i386/i486/pthread_cond_wait.S
583469ac AM	29	@@ -134,7 +134,6 @@ __pthread_cond_wait:
	30	cmpl $PI_BIT, %eax
	31	jne 18f
	32
	33	-90:
	34	movl $(FUTEX_WAIT_REQUEUE_PI\|FUTEX_PRIVATE_FLAG), %ecx
	35	movl %ebp, %edx
	36	xorl %esi, %esi
	37	@@ -148,9 +147,6 @@ __pthread_cond_wait:
	38	sete 16(%esp)
	39	je 19f
	40
	41	- cmpl $-EAGAIN, %eax
	42	- je 91f
	43	-
	44	/* Normal and PI futexes dont mix. Use normal futex functions only
	45	if the kernel does not support the PI futex functions. */
	46	cmpl $-ENOSYS, %eax
	47	@@ -395,78 +391,6 @@ __pthread_cond_wait:
	48	#endif
	49	call __lll_unlock_wake
	50	jmp 11b
	51	-
	52	-91:
	53	-.LcleanupSTART2:
	54	- /* FUTEX_WAIT_REQUEUE_PI returned EAGAIN. We need to
	55	- call it again. */
	56	-
	57	- /* Get internal lock. */
	58	- movl $1, %edx
	59	- xorl %eax, %eax
	60	- LOCK
	61	-#if cond_lock == 0
	62	- cmpxchgl %edx, (%ebx)
	63	-#else
	64	- cmpxchgl %edx, cond_lock(%ebx)
	65	-#endif
	66	- jz 92f
	67	-
	68	-#if cond_lock == 0
	69	- movl %ebx, %edx
	70	-#else
	71	- leal cond_lock(%ebx), %edx
	72	-#endif
	73	-#if (LLL_SHARED-LLL_PRIVATE) > 255
	74	- xorl %ecx, %ecx
	75	-#endif
	76	- cmpl $-1, dep_mutex(%ebx)
	77	- setne %cl
	78	- subl $1, %ecx
	79	- andl $(LLL_SHARED-LLL_PRIVATE), %ecx
	80	-#if LLL_PRIVATE != 0
	81	- addl $LLL_PRIVATE, %ecx
	82	-#endif
	83	- call __lll_lock_wait
	84	-
	85	-92:
	86	- /* Increment the cond_futex value again, so it can be used as a new
	87	- expected value. */
	88	- addl $1, cond_futex(%ebx)
	89	- movl cond_futex(%ebx), %ebp
	90	-
	91	- /* Unlock. */
	92	- LOCK
93	-#if cond_lock == 0
94	- subl $1, (%ebx)
95	-#else
96	- subl $1, cond_lock(%ebx)
97	-#endif
98	- je 93f
99	-#if cond_lock == 0
100	- movl %ebx, %eax
101	-#else
102	- leal cond_lock(%ebx), %eax
103	-#endif
104	-#if (LLL_SHARED-LLL_PRIVATE) > 255
105	- xorl %ecx, %ecx
106	-#endif
107	- cmpl $-1, dep_mutex(%ebx)
108	- setne %cl
109	- subl $1, %ecx
110	- andl $(LLL_SHARED-LLL_PRIVATE), %ecx
111	-#if LLL_PRIVATE != 0
112	- addl $LLL_PRIVATE, %ecx
113	-#endif
114	- call __lll_unlock_wake
115	-
116	-93:
117	- /* Set the rest of SYS_futex args for FUTEX_WAIT_REQUEUE_PI. */
118	- xorl %ecx, %ecx
119	- movl dep_mutex(%ebx), %edi
120	- jmp 90b
121	-.LcleanupEND2:
122	-
123	.size __pthread_cond_wait, .-__pthread_cond_wait
124	versioned_symbol (libpthread, __pthread_cond_wait, pthread_cond_wait,
125	GLIBC_2_3_2)
126	@@ -639,10 +563,6 @@ __condvar_w_cleanup:
127	.long .LcleanupEND-.Lsub_cond_futex
128	.long __condvar_w_cleanup-.LSTARTCODE
129	.uleb128 0
130	- .long .LcleanupSTART2-.LSTARTCODE
131	- .long .LcleanupEND2-.LcleanupSTART2
132	- .long __condvar_w_cleanup-.LSTARTCODE
133	- .uleb128 0
134	.long .LcallUR-.LSTARTCODE
135	.long .LENDCODE-.LcallUR
136	.long 0
0f2e926c	137	diff --git a/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S b/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S
583469ac	138	index d837d15..7535baa 100644
0f2e926c AM	139	--- a/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S
0f2e926c AM	140	+++ b/nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S
583469ac AM	141	@@ -23,7 +23,6 @@
	142	#include <lowlevelcond.h>
	143	#include <tcb-offsets.h>
	144	#include <pthread-pi-defines.h>
	145	-#include <pthread-errnos.h>
0f2e926c	146	#include <stap-probe.h>
583469ac AM	147
583469ac AM	148	#include <kernel-features.h>
583469ac AM	149	@@ -134,14 +133,11 @@ __pthread_cond_wait:
	150	cmpl $PI_BIT, %eax
	151	jne 61f
	152
	153	-90:
	154	movl $(FUTEX_WAIT_REQUEUE_PI\|FUTEX_PRIVATE_FLAG), %esi
	155	movl $SYS_futex, %eax
	156	syscall
	157
	158	movl $1, %r8d
	159	- cmpq $-EAGAIN, %rax
	160	- je 91f
	161	#ifdef __ASSUME_REQUEUE_PI
	162	jmp 62f
	163	#else
	164	@@ -328,70 +324,6 @@ __pthread_cond_wait:
	165
	166	13: movq %r10, %rax
	167	jmp 14b
	168	-
	169	-91:
	170	-.LcleanupSTART2:
	171	- /* FUTEX_WAIT_REQUEUE_PI returned EAGAIN. We need to
	172	- call it again. */
	173	- movq 8(%rsp), %rdi
	174	-
	175	- /* Get internal lock. */
	176	- movl $1, %esi
	177	- xorl %eax, %eax
	178	- LOCK
	179	-#if cond_lock == 0
	180	- cmpxchgl %esi, (%rdi)
	181	-#else
	182	- cmpxchgl %esi, cond_lock(%rdi)
	183	-#endif
	184	- jz 92f
	185	-
	186	-#if cond_lock != 0
	187	- addq $cond_lock, %rdi
	188	-#endif
0f2e926c	189	- LP_OP(cmp) $-1, dep_mutex-cond_lock(%rdi)
583469ac AM	190	- movl $LLL_PRIVATE, %eax
	191	- movl $LLL_SHARED, %esi
	192	- cmovne %eax, %esi
	193	- callq __lll_lock_wait
	194	-#if cond_lock != 0
	195	- subq $cond_lock, %rdi
	196	-#endif
	197	-92:
	198	- /* Increment the cond_futex value again, so it can be used as a new
	199	- expected value. */
	200	- incl cond_futex(%rdi)
	201	- movl cond_futex(%rdi), %edx
	202	-
	203	- /* Release internal lock. */
	204	- LOCK
	205	-#if cond_lock == 0
	206	- decl (%rdi)
	207	-#else
	208	- decl cond_lock(%rdi)
	209	-#endif
	210	- jz 93f
	211	-
	212	-#if cond_lock != 0
	213	- addq $cond_lock, %rdi
	214	-#endif
0f2e926c	215	- LP_OP(cmp) $-1, dep_mutex-cond_lock(%rdi)
583469ac AM	216	- movl $LLL_PRIVATE, %eax
	217	- movl $LLL_SHARED, %esi
	218	- cmovne %eax, %esi
	219	- /* The call preserves %rdx. */
	220	- callq __lll_unlock_wake
	221	-#if cond_lock != 0
	222	- subq $cond_lock, %rdi
	223	-#endif
	224	-93:
	225	- /* Set the rest of SYS_futex args for FUTEX_WAIT_REQUEUE_PI. */
	226	- xorq %r10, %r10
0f2e926c	227	- mov dep_mutex(%rdi), %R8_LP
583469ac AM	228	- leaq cond_futex(%rdi), %rdi
	229	- jmp 90b
	230	-.LcleanupEND2:
	231	-
	232	.size __pthread_cond_wait, .-__pthread_cond_wait
	233	versioned_symbol (libpthread, __pthread_cond_wait, pthread_cond_wait,
	234	GLIBC_2_3_2)
	235	@@ -544,15 +476,11 @@ __condvar_cleanup1:
	236	.uleb128 .LcleanupSTART-.LSTARTCODE
	237	.uleb128 .LcleanupEND-.LcleanupSTART
	238	.uleb128 __condvar_cleanup1-.LSTARTCODE
	239	- .uleb128 0
	240	- .uleb128 .LcleanupSTART2-.LSTARTCODE
	241	- .uleb128 .LcleanupEND2-.LcleanupSTART2
	242	- .uleb128 __condvar_cleanup1-.LSTARTCODE
	243	- .uleb128 0
	244	+ .uleb128 0
	245	.uleb128 .LcallUR-.LSTARTCODE
	246	.uleb128 .LENDCODE-.LcallUR
	247	.uleb128 0
	248	- .uleb128 0
	249	+ .uleb128 0
	250	.Lcstend:
	251
	252