Chuck Ebbert <[EMAIL PROTECTED]> writes: > > There is a fixup, so this should never happen. But the lock instruction > was replaced with a nop by the altinstruction code, and that makes the fixup > address wrong. AFAICT we don't fix up the exception table when we replace > a lock with a nop, which makes the fixup table point to the nop instead > of the cmpxchg instruction and causes us to miss the fixup.
Indeed. Nasty issue. A quick fix would be to add another fixup to handle both cases I checked the other LOCK_PREFIX users and they look ok. Does this fix it? -Andi (untested) --- Add exception handlers for both the LOCK and no LOCK prefix case in futex. Hopefully fixes https://bugzilla.redhat.com/show_bug.cgi?id=429412 Signed-off-by: Andi Kleen <[EMAIL PROTECTED]> Index: linux/include/asm-x86/futex.h =================================================================== --- linux.orig/include/asm-x86/futex.h +++ linux/include/asm-x86/futex.h @@ -30,7 +30,7 @@ "1: movl %2, %0\n \ movl %0, %3\n" \ insn "\n" \ -"2: " LOCK_PREFIX "cmpxchgl %3, %2\n \ +"2: " LOCK_PREFIX "\n5: cmpxchgl %3, %2\n \ jnz 1b\n \ 3: .section .fixup,\"ax\"\n \ 4: mov %5, %1\n \ @@ -38,7 +38,7 @@ .previous\n \ .section __ex_table,\"a\"\n \ .align 8\n" \ - _ASM_PTR "1b,4b,2b,4b\n \ + _ASM_PTR "1b,4b,2b,4b,5b,4b\n \ .previous" \ : "=&a" (oldval), "=&r" (ret), "+m" (*uaddr), \ "=&r" (tem) \ -- 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/
