From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751618Ab2I3TlQ (ORCPT ); Sun, 30 Sep 2012 15:41:16 -0400 Received: from mx1.redhat.com ([209.132.183.28]:24005 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751515Ab2I3Tkj (ORCPT ); Sun, 30 Sep 2012 15:40:39 -0400 Date: Sun, 30 Sep 2012 21:42:04 +0200 From: Oleg Nesterov To: Ingo Molnar , Peter Zijlstra , Srikar Dronamraju Cc: Ananth N Mavinakayanahalli , Anton Arapov , Sebastian Andrzej Siewior , linux-kernel@vger.kernel.org Subject: [PATCH 3/7] uprobes: Do not delete uprobe if uprobe_unregister() fails Message-ID: <20120930194204.GA11326@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120930194119.GA11278@redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org delete_uprobe() must not be called if register_for_each_vma(false) fails to remove all breakpoints, __uprobe_unregister() is correct. The problem is that register_for_each_vma(false) always returns 0 and thus this logic does not work. 1. Change verify_opcode() to return 0 rather than -EINVAL when unregister detects the !is_swbp insn, we can treat this case as success and currently unregister paths ignore the error code anyway. 2. Change remove_breakpoint() to propagate the error code from write_opcode(). 3. Change register_for_each_vma(is_register => false) to remove as much breakpoints as possible but return non-zero if remove_breakpoint() fails at least once. Signed-off-by: Oleg Nesterov --- kernel/events/uprobes.c | 12 ++++++------ 1 files changed, 6 insertions(+), 6 deletions(-) diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 3ec114c..6058231 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -203,7 +203,7 @@ static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t return 0; } else { if (!is_swbp) /* unregister: was it changed by us? */ - return -EINVAL; + return 0; } return 1; @@ -616,15 +616,15 @@ install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, return ret; } -static void +static int remove_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, unsigned long vaddr) { /* can happen if uprobe_register() fails */ if (!test_bit(MMF_HAS_UPROBES, &mm->flags)) - return; + return 0; set_bit(MMF_RECALC_UPROBES, &mm->flags); - set_orig_insn(&uprobe->arch, mm, vaddr); + return set_orig_insn(&uprobe->arch, mm, vaddr); } /* @@ -740,7 +740,7 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register) struct mm_struct *mm = info->mm; struct vm_area_struct *vma; - if (err) + if (err && is_register) goto free; down_write(&mm->mmap_sem); @@ -756,7 +756,7 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register) if (is_register) err = install_breakpoint(uprobe, mm, vma, info->vaddr); else - remove_breakpoint(uprobe, mm, info->vaddr); + err |= remove_breakpoint(uprobe, mm, info->vaddr); unlock: up_write(&mm->mmap_sem); -- 1.5.5.1