[PATCH] Don't use SYSGOOD for ptrace singlestep

The ptrace single step mode should not use the SYSGOOD bit and should not
report SIGTRAP|0x80 to the ptrace parent.  The following patch add an
explicit check and to not add 0x80 in this is a singlestep trap.
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/i386/kernel/ptrace.c

@@ -546,8 +546,8 @@ void do_syscall_trace(struct pt_regs *regs, int entryexit)
 		return;
 	/* the 0x80 provides a way for the tracing parent to distinguish
 	   between a syscall stop and SIGTRAP delivery */
-	ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
-				 ? 0x80 : 0));
+	ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) &&
+				 !test_thread_flag(TIF_SINGLESTEP) ? 0x80 : 0));
 
 	/*
 	 * this isn't the same as continuing with a signal, but it will do