--- releng/8.1/sys/amd64/amd64/trap.c 2012/06/18 20:19:07 237240 +++ releng/8.1/sys/amd64/amd64/trap.c 2012/06/18 20:48:21 237241 @@ -972,23 +972,6 @@ ksi.ksi_code = TRAP_TRACE; ksi.ksi_addr = (void *)frame->tf_rip; trapsignal(td, &ksi); - - /* - * If the user-supplied value of %rip is not a canonical - * address, then some CPUs will trigger a ring 0 #GP during - * the sysret instruction. However, the fault handler would - * execute with the user's %gs and %rsp in ring 0 which would - * not be safe. Instead, preemptively kill the thread with a - * SIGBUS. - */ - if (td->td_frame->tf_rip >= VM_MAXUSER_ADDRESS) { - ksiginfo_init_trap(&ksi); - ksi.ksi_signo = SIGBUS; - ksi.ksi_code = BUS_OBJERR; - ksi.ksi_trapno = T_PROTFLT; - ksi.ksi_addr = (void *)td->td_frame->tf_rip; - trapsignal(td, &ksi); - } } /* @@ -1027,4 +1010,21 @@ STOPEVENT(p, S_SCX, sa.code); PTRACESTOP_SC(p, td, S_PT_SCX); + + /* + * If the user-supplied value of %rip is not a canonical + * address, then some CPUs will trigger a ring 0 #GP during + * the sysret instruction. However, the fault handler would + * execute with the user's %gs and %rsp in ring 0 which would + * not be safe. Instead, preemptively kill the thread with a + * SIGBUS. + */ + if (td->td_frame->tf_rip >= VM_MAXUSER_ADDRESS) { + ksiginfo_init_trap(&ksi); + ksi.ksi_signo = SIGBUS; + ksi.ksi_code = BUS_OBJERR; + ksi.ksi_trapno = T_PROTFLT; + ksi.ksi_addr = (void *)td->td_frame->tf_rip; + trapsignal(td, &ksi); + } }