From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030319Ab2HHRmT (ORCPT ); Wed, 8 Aug 2012 13:42:19 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55960 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759052Ab2HHRlC (ORCPT ); Wed, 8 Aug 2012 13:41:02 -0400 Date: Wed, 8 Aug 2012 19:37:39 +0200 From: Oleg Nesterov To: Ingo Molnar , Peter Zijlstra , Srikar Dronamraju Cc: Ananth N Mavinakayanahalli , Anton Arapov , linux-kernel@vger.kernel.org Subject: [PATCH 2/7] uprobes: kill dup_mmap()->uprobe_mmap(), simplify uprobe_mmap/munmap Message-ID: <20120808173739.GA13259@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120808173659.GA13220@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 1. Kill dup_mmap()->uprobe_mmap(), it was only needed to calculate new_mm->uprobes_state.count removed by the previous patch. If the forking process has a pending uprobe (int3) in vma, it will be copied by copy_page_range(), note that it checks vma->anon_vma so "Don't copy ptes" is not possible after install_breakpoint() which does anon_vma_prepare(). 2. Remove is_swbp_at_addr() and "int count" in uprobe_mmap(). Again, this was needed for uprobes_state.count. As a side effect this fixes the bug pointed out by Srikar, this code lacked the necessary put_uprobe(). 3. uprobe_munmap() becomes a nop after the previous patch. Remove the meaningless code but do not remove the helper, we will need it. Signed-off-by: Oleg Nesterov --- kernel/events/uprobes.c | 30 +++--------------------------- kernel/fork.c | 3 --- 2 files changed, 3 insertions(+), 30 deletions(-) diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index f0bb387..08ea627 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1012,7 +1012,7 @@ int uprobe_mmap(struct vm_area_struct *vma) struct list_head tmp_list; struct uprobe *uprobe, *u; struct inode *inode; - int ret, count; + int ret; if (!atomic_read(&uprobe_events) || !valid_vma(vma, true)) return 0; @@ -1025,8 +1025,6 @@ int uprobe_mmap(struct vm_area_struct *vma) build_probe_list(inode, vma, vma->vm_start, vma->vm_end, &tmp_list); ret = 0; - count = 0; - list_for_each_entry_safe(uprobe, u, &tmp_list, pending_list) { if (!ret) { unsigned long vaddr = offset_to_vaddr(vma, uprobe->offset); @@ -1036,19 +1034,11 @@ int uprobe_mmap(struct vm_area_struct *vma) * We can race against uprobe_register(), see the * comment near uprobe_hash(). */ - if (ret == -EEXIST) { + if (ret == -EEXIST) ret = 0; - - if (!is_swbp_at_addr(vma->vm_mm, vaddr)) - continue; - } - - if (!ret) - count++; } put_uprobe(uprobe); } - mutex_unlock(uprobes_mmap_hash(inode)); return ret; @@ -1059,27 +1049,13 @@ int uprobe_mmap(struct vm_area_struct *vma) */ void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end) { - struct list_head tmp_list; - struct uprobe *uprobe, *u; - struct inode *inode; - if (!atomic_read(&uprobe_events) || !valid_vma(vma, false)) return; if (!atomic_read(&vma->vm_mm->mm_users)) /* called by mmput() ? */ return; - inode = vma->vm_file->f_mapping->host; - if (!inode) - return; - - mutex_lock(uprobes_mmap_hash(inode)); - build_probe_list(inode, vma, start, end, &tmp_list); - - list_for_each_entry_safe(uprobe, u, &tmp_list, pending_list) { - put_uprobe(uprobe); - } - mutex_unlock(uprobes_mmap_hash(inode)); + /* TODO: unmapping uprobe(s) will need more work */ } /* Slot allocation for XOL */ diff --git a/kernel/fork.c b/kernel/fork.c index 54bb88a..0e419ab 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -453,9 +453,6 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) if (retval) goto out; - - if (file) - uprobe_mmap(tmp); } /* a new mm has just been created */ arch_dup_mmap(oldmm, mm); -- 1.5.5.1