From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755989Ab1KJTHv (ORCPT ); Thu, 10 Nov 2011 14:07:51 -0500 Received: from e28smtp07.in.ibm.com ([122.248.162.7]:51839 "EHLO e28smtp07.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753009Ab1KJTHq (ORCPT ); Thu, 10 Nov 2011 14:07:46 -0500 From: Srikar Dronamraju To: Peter Zijlstra , Linus Torvalds Cc: Oleg Nesterov , Andrew Morton , LKML , Linux-mm , Ingo Molnar , Andi Kleen , Christoph Hellwig , Steven Rostedt , Roland McGrath , Thomas Gleixner , Masami Hiramatsu , Arnaldo Carvalho de Melo , Anton Arapov , Ananth N Mavinakayanahalli , Jim Keniston , Stephen Wilson Date: Fri, 11 Nov 2011 00:12:37 +0530 Message-Id: <20111110184237.11361.87061.sendpatchset@srdronam.in.ibm.com> In-Reply-To: <20111110183725.11361.57827.sendpatchset@srdronam.in.ibm.com> References: <20111110183725.11361.57827.sendpatchset@srdronam.in.ibm.com> Subject: [PATCH v6 3.2-rc1 25/28] uprobes: call post_xol() unconditionally x-cbid: 11111019-8878-0000-0000-0000002CF4B1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Kill sstep_complete(), change uprobe_notify_resume() to use post_xol() unconditionally. It is wrong to assume that regs->ip always changes after the step. rep or jmp/call to self for example. We know that this task has already done the step, we can rely on DIE_DEBUG notification. Original-patch-from: Oleg Nesterov Signed-off-by: Srikar Dronamraju --- include/linux/uprobes.h | 3 ++- kernel/uprobes.c | 40 ++++++++++++---------------------------- 2 files changed, 14 insertions(+), 29 deletions(-) diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h index add5222..70d639c 100644 --- a/include/linux/uprobes.h +++ b/include/linux/uprobes.h @@ -74,7 +74,8 @@ struct uprobe { enum uprobe_task_state { UTASK_RUNNING, UTASK_BP_HIT, - UTASK_SSTEP + UTASK_SSTEP, + UTASK_SSTEP_ACK, }; /* diff --git a/kernel/uprobes.c b/kernel/uprobes.c index 9e73cef..13b1d68 100644 --- a/kernel/uprobes.c +++ b/kernel/uprobes.c @@ -1316,24 +1316,6 @@ static int pre_ssout(struct uprobe *uprobe, struct pt_regs *regs, } /* - * Verify from Instruction Pointer if singlestep has indeed occurred. - * If Singlestep has occurred, then do post singlestep fix-ups. - */ -static bool sstep_complete(struct uprobe *uprobe, struct pt_regs *regs) -{ - unsigned long vaddr = instruction_pointer(regs); - - /* - * If we have executed out of line, Instruction pointer - * cannot be same as virtual address of XOL slot. - */ - if (vaddr == current->utask->xol_vaddr) - return false; - post_xol(uprobe, regs); - return true; -} - -/* * uprobe_notify_resume gets called in task context just before returning * to userspace. * @@ -1381,17 +1363,18 @@ void uprobe_notify_resume(struct pt_regs *regs) else /* Cannot Singlestep; re-execute the instruction. */ goto cleanup_ret; - } else if (utask->state == UTASK_SSTEP) { + } else { u = utask->active_uprobe; - if (sstep_complete(u, regs)) { - put_uprobe(u); - utask->active_uprobe = NULL; - utask->state = UTASK_RUNNING; - user_disable_single_step(current); - xol_free_insn_slot(current); - - /* TODO Stop queueing signals. */ - } + if (utask->state == UTASK_SSTEP_ACK) + post_xol(u, regs); + else + WARN_ON_ONCE(1); + + put_uprobe(u); + utask->active_uprobe = NULL; + utask->state = UTASK_RUNNING; + user_disable_single_step(current); + xol_free_insn_slot(current); } return; @@ -1441,6 +1424,7 @@ int uprobe_post_notifier(struct pt_regs *regs) /* task is currently not uprobed */ return 0; + utask->state = UTASK_SSTEP_ACK; set_thread_flag(TIF_UPROBE); return 1; }