From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754076Ab2FRI7L (ORCPT ); Mon, 18 Jun 2012 04:59:11 -0400 Received: from terminus.zytor.com ([198.137.202.10]:40550 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752137Ab2FRI7J (ORCPT ); Mon, 18 Jun 2012 04:59:09 -0400 Date: Mon, 18 Jun 2012 01:58:49 -0700 From: tip-bot for Oleg Nesterov Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org, peterz@infradead.org, ananth@in.ibm.com, anton@redhat.com, srikar@linux.vnet.ibm.com, tglx@linutronix.de, oleg@redhat.com Reply-To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, peterz@infradead.org, ananth@in.ibm.com, anton@redhat.com, srikar@linux.vnet.ibm.com, tglx@linutronix.de, oleg@redhat.com In-Reply-To: <20120615154350.GA9611@redhat.com> References: <20120615154350.GA9611@redhat.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] uprobes: Move BUG_ON(UPROBE_SWBP_INSN_SIZE) from write_opcode() to install_breakpoint() Git-Commit-ID: d9c4a30e82614d43b55893a73f31e7284007ce82 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.6 (terminus.zytor.com [127.0.0.1]); Mon, 18 Jun 2012 01:58:55 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: d9c4a30e82614d43b55893a73f31e7284007ce82 Gitweb: http://git.kernel.org/tip/d9c4a30e82614d43b55893a73f31e7284007ce82 Author: Oleg Nesterov AuthorDate: Fri, 15 Jun 2012 17:43:50 +0200 Committer: Ingo Molnar CommitDate: Sat, 16 Jun 2012 09:10:47 +0200 uprobes: Move BUG_ON(UPROBE_SWBP_INSN_SIZE) from write_opcode() to install_breakpoint() write_opcode() ensures that UPROBE_SWBP_INSN doesn't cross the page boundary. This looks a bit confusing, the check does not depend on vaddr and it is enough to do it only once right after install_breakpoint()->arch_uprobe_analyze_insn(). Signed-off-by: Oleg Nesterov Acked-by: Srikar Dronamraju Acked-by: Ananth N Mavinakayanahalli Cc: Anton Arapov Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20120615154350.GA9611@redhat.com Signed-off-by: Ingo Molnar --- kernel/events/uprobes.c | 11 +++++------ 1 files changed, 5 insertions(+), 6 deletions(-) diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 14c71a2..b9c61bd 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -210,7 +210,6 @@ static int write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm, void *vaddr_old, *vaddr_new; struct vm_area_struct *vma; struct uprobe *uprobe; - unsigned long pgoff; int ret; retry: /* Read the page with vaddr into memory */ @@ -251,11 +250,7 @@ retry: vaddr_new = kmap_atomic(new_page); memcpy(vaddr_new, vaddr_old, PAGE_SIZE); - - /* poke the new insn in, ASSUMES we don't cross page boundary */ - pgoff = (vaddr & ~PAGE_MASK); - BUG_ON(pgoff + UPROBE_SWBP_INSN_SIZE > PAGE_SIZE); - memcpy(vaddr_new + pgoff, &opcode, UPROBE_SWBP_INSN_SIZE); + memcpy(vaddr_new + (vaddr & ~PAGE_MASK), &opcode, UPROBE_SWBP_INSN_SIZE); kunmap_atomic(vaddr_new); kunmap_atomic(vaddr_old); @@ -699,6 +694,10 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, if (ret) return ret; + /* write_opcode() assumes we don't cross page boundary */ + BUG_ON((uprobe->offset & ~PAGE_MASK) + + UPROBE_SWBP_INSN_SIZE > PAGE_SIZE); + uprobe->flags |= UPROBE_COPY_INSN; }