Re: [patch 0/8] 2.6.23-stable review

From: Chuck Ebbert
Date: Sat Feb 23 2008 - 11:57:40 EST


On 02/22/2008 07:17 PM, Greg KH wrote:
> This is the start of the stable review cycle for the 2.6.23.17 release.
> There are 8 patches in this series, all will be posted as a response
> to this one. If anyone has any issues with these being applied, please
> let us know. If anyone is a maintainer of the proper subsystem, and
> wants to add a Signed-off-by: line to the patch, please respond with it.
>
> These patches are sent out with a number of different people on the
> Cc: line. If you wish to be a reviewer, please email stable@xxxxxxxxxx
> to add your name to the list. If you want to be off the reviewer list,
> also email us.
>
> Responses should be made by Tuesday, Feb 25, 2008, 00:10:00 UTC.
> Anything received after that time might be too late.
>

Still missing this one? (trivial backport)

Gitweb: http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=9d55b9923a1b7ea8193b8875c57ec940dc2ff027
Commit: 9d55b9923a1b7ea8193b8875c57ec940dc2ff027
Parent: 5df7fa1c62146a0933767d040d400013310dbcc7
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Fri Feb 1 17:45:14 2008 +0100
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Fri Feb 1 17:45:14 2008 +0100

x86: replace LOCK_PREFIX in futex.h

The exception fixup for the futex macros __futex_atomic_op1/2 and
futex_atomic_cmpxchg_inatomic() is missing an entry when the lock
prefix is replaced by a NOP via SMP alternatives.

Chuck Ebert tracked this down from the information provided in:
https://bugzilla.redhat.com/show_bug.cgi?id=429412

A possible solution would be to add another fixup after the
LOCK_PREFIX, so both the LOCK and NOP case have their own entry in the
exception table, but it's not really worth the trouble.

Simply replace LOCK_PREFIX with lock and keep those untouched by SMP
alternatives.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

Signed-off-by: Ingo Molnar <mingo@xxxxxxx>

[cebbert@xxxxxxxxxx: backport to 2.6.23]

---
include/asm-i386/futex.h | 6 +++---
include/asm-x86_64/futex.h | 6 +++---
2 files changed, 6 insertions(+), 6 deletions(-)

--- vanilla.orig/include/asm-i386/futex.h
+++ vanilla/include/asm-i386/futex.h
@@ -28,7 +28,7 @@
"1: movl %2, %0\n\
movl %0, %3\n" \
insn "\n" \
-"2: " LOCK_PREFIX "cmpxchgl %3, %2\n\
+"2: lock ; cmpxchgl %3, %2\n\
jnz 1b\n\
3: .section .fixup,\"ax\"\n\
4: mov %5, %1\n\
@@ -68,7 +68,7 @@ futex_atomic_op_inuser (int encoded_op,
#endif
switch (op) {
case FUTEX_OP_ADD:
- __futex_atomic_op1(LOCK_PREFIX "xaddl %0, %2", ret,
+ __futex_atomic_op1("lock ; xaddl %0, %2", ret,
oldval, uaddr, oparg);
break;
case FUTEX_OP_OR:
@@ -111,7 +111,7 @@ futex_atomic_cmpxchg_inatomic(int __user
return -EFAULT;

__asm__ __volatile__(
- "1: " LOCK_PREFIX "cmpxchgl %3, %1 \n"
+ "1: lock ; cmpxchgl %3, %1 \n"

"2: .section .fixup, \"ax\" \n"
"3: mov %2, %0 \n"
--- vanilla.orig/include/asm-x86_64/futex.h
+++ vanilla/include/asm-x86_64/futex.h
@@ -27,7 +27,7 @@
"1: movl %2, %0\n\
movl %0, %3\n" \
insn "\n" \
-"2: " LOCK_PREFIX "cmpxchgl %3, %2\n\
+"2: lock ; cmpxchgl %3, %2\n\
jnz 1b\n\
3: .section .fixup,\"ax\"\n\
4: mov %5, %1\n\
@@ -62,7 +62,7 @@ futex_atomic_op_inuser (int encoded_op,
__futex_atomic_op1("xchgl %0, %2", ret, oldval, uaddr, oparg);
break;
case FUTEX_OP_ADD:
- __futex_atomic_op1(LOCK_PREFIX "xaddl %0, %2", ret, oldval,
+ __futex_atomic_op1("lock ; xaddl %0, %2", ret, oldval,
uaddr, oparg);
break;
case FUTEX_OP_OR:
@@ -101,7 +101,7 @@ futex_atomic_cmpxchg_inatomic(int __user
return -EFAULT;

__asm__ __volatile__(
- "1: " LOCK_PREFIX "cmpxchgl %3, %1 \n"
+ "1: lock ; cmpxchgl %3, %1 \n"

"2: .section .fixup, \"ax\" \n"
"3: mov %2, %0 \n"


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