Date: Mon, 25 Jun 2012 09:41:48 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-9@freebsd.org Subject: svn commit: r237559 - stable/9/sys/amd64/amd64 Message-ID: <201206250941.q5P9fmFS063468@svn.freebsd.org>
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Author: kib Date: Mon Jun 25 09:41:47 2012 New Revision: 237559 URL: http://svn.freebsd.org/changeset/base/237559 Log: MFC r237243: Adjust the fix in r236953, by not generating the signal manually, but performing the return to usermode using full return path. Modified: stable/9/sys/amd64/amd64/trap.c Directory Properties: stable/9/sys/ (props changed) Modified: stable/9/sys/amd64/amd64/trap.c ============================================================================== --- stable/9/sys/amd64/amd64/trap.c Mon Jun 25 08:34:14 2012 (r237558) +++ stable/9/sys/amd64/amd64/trap.c Mon Jun 25 09:41:47 2012 (r237559) @@ -982,16 +982,10 @@ amd64_syscall(struct thread *td, int tra * 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. + * execute in ring 0 with the user's %gs and %rsp which would + * not be safe. Instead, use the full return path which + * catches the problem safely. */ - 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); - } + if (td->td_frame->tf_rip >= VM_MAXUSER_ADDRESS) + set_pcb_flags(td->td_pcb, PCB_FULL_IRET); }
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