On 01/22/2008 07:35 AM, Thomas Gleixner wrote: > > That's a long standing bug in both the PI futex and the standard futex > code. Needs to go to stable as well. >
Here's the 2.6.23 version: Subject: x86: fix missing exception entry for SMP alternatives in futex macros From: Thomas Gleixner <[EMAIL PROTECTED]> The exception fixup for the futex macros __futex_atomic_op2 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 The solution is to add another fixup after the LOCK_PREFIX, so both the LOCK and NOP case have their own entry in the exception table. The solution was pointed out by Andi Kleen. Signed-off-by: Thomas Gleixner <[EMAIL PROTECTED]> Acked-by: Ingo Molnar <[EMAIL PROTECTED]> --- include/asm-i386/futex.h | 8 ++++---- include/asm-x86_64/futex.h | 8 ++++---- 2 files changed, 8 insertions(+), 8 deletions(-) Index: linux-2.6/include/asm-i386/futex.h =================================================================== --- linux-2.6.orig/include/asm-i386/futex.h 2008-01-22 13:13:10.000000000 +0100 +++ linux-2.6/include/asm-i386/futex.h 2008-01-22 13:13:49.000000000 +0100 @@ -28,7 +28,7 @@ "1: movl %2, %0\n\ movl %0, %3\n" \ insn "\n" \ -"2: " LOCK_PREFIX "cmpxchgl %3, %2\n\ +"2: " LOCK_PREFIX "\n 5: cmpxchgl %3, %2\n\ jnz 1b\n\ 3: .section .fixup,\"ax\"\n\ 4: mov %5, %1\n\ @@ -36,7 +36,7 @@ .previous\n\ .section __ex_table,\"a\"\n\ .align 8\n\ - .long 1b,4b,2b,4b\n\ + .long 1b,4b,2b,4b,5b,4b\n\ .previous" \ : "=&a" (oldval), "=&r" (ret), "+m" (*uaddr), \ "=&r" (tem) \ @@ -111,7 +111,7 @@ futex_atomic_cmpxchg_inatomic(int __user return -EFAULT; __asm__ __volatile__( - "1: " LOCK_PREFIX "cmpxchgl %3, %1 \n" + "1: " LOCK_PREFIX "\n 4: cmpxchgl %3, %1 \n" "2: .section .fixup, \"ax\" \n" "3: mov %2, %0 \n" @@ -120,7 +120,7 @@ futex_atomic_cmpxchg_inatomic(int __user " .section __ex_table, \"a\" \n" " .align 8 \n" - " .long 1b,3b \n" + " .long 1b,3b,4b,3b \n" " .previous \n" : "=a" (oldval), "+m" (*uaddr) Index: linux-2.6/include/asm-x86_64/futex.h =================================================================== --- linux-2.6.orig/include/asm-x86_64/futex.h 2008-01-22 13:13:10.000000000 +0100 +++ linux-2.6/include/asm-x86_64/futex.h 2008-01-22 13:13:49.000000000 +0100 @@ -27,7 +27,7 @@ "1: movl %2, %0\n\ movl %0, %3\n" \ insn "\n" \ -"2: " LOCK_PREFIX "cmpxchgl %3, %2\n\ +"2: " LOCK_PREFIX "\n 5: cmpxchgl %3, %2\n\ jnz 1b\n\ 3: .section .fixup,\"ax\"\n\ 4: mov %5, %1\n\ @@ -35,7 +35,7 @@ .previous\n\ .section __ex_table,\"a\"\n\ .align 8\n\ - .quad 1b,4b,2b,4b\n\ + .quad 1b,4b,2b,4b,5b,4b\n\ .previous" \ : "=&a" (oldval), "=&r" (ret), "=m" (*uaddr), \ "=&r" (tem) \ @@ -101,7 +101,7 @@ futex_atomic_cmpxchg_inatomic(int __user return -EFAULT; __asm__ __volatile__( - "1: " LOCK_PREFIX "cmpxchgl %3, %1 \n" + "1: " LOCK_PREFIX "\n 4: cmpxchgl %3, %1 \n" "2: .section .fixup, \"ax\" \n" "3: mov %2, %0 \n" @@ -110,7 +110,7 @@ futex_atomic_cmpxchg_inatomic(int __user " .section __ex_table, \"a\" \n" " .align 8 \n" - " .quad 1b,3b \n" + " .quad 1b,3b,4b,3b \n" " .previous \n" : "=a" (oldval), "=m" (*uaddr) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
