From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760271AbZE1LmZ (ORCPT ); Thu, 28 May 2009 07:42:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755762AbZE1Lkf (ORCPT ); Thu, 28 May 2009 07:40:35 -0400 Received: from mx2.redhat.com ([66.187.237.31]:57809 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755545AbZE1Lkc (ORCPT ); Thu, 28 May 2009 07:40:32 -0400 Date: Thu, 28 May 2009 13:35:54 +0200 From: Oleg Nesterov To: Roland McGrath Cc: Christoph Hellwig , Ingo Molnar , linux-kernel@vger.kernel.org Subject: [RFC PATCH 8/12 v2] ptrace: mv task->parent ptrace_ctx->tracer Message-ID: <20090528113554.GA18712@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline 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 Move task_struct->parent into ptrace_ctx->tracer and change the users accordingly. The next patch will add the helper to simplify/cleanup the usage of ->tracer. include/linux/sched.h | 8 +------- include/linux/init_task.h | 1 - include/linux/ptrace.h | 18 ++++++++++-------- include/linux/tracehook.h | 4 ++-- kernel/ptrace.c | 8 ++++---- kernel/exit.c | 6 +----- kernel/signal.c | 20 +++++++++++++------- 7 files changed, 31 insertions(+), 34 deletions(-) --- PTRACE/include/linux/sched.h~7_MV_PARENT 2009-05-28 08:23:13.000000000 +0200 +++ PTRACE/include/linux/sched.h 2009-05-28 08:41:11.000000000 +0200 @@ -1186,13 +1186,7 @@ struct task_struct { /* Canary value for the -fstack-protector gcc feature */ unsigned long stack_canary; - /* - * pointers to (original) parent process, youngest child, younger sibling, - * older sibling, respectively. (p->father can be replaced with - * p->real_parent->pid) - */ - struct task_struct *real_parent; /* real parent process */ - struct task_struct *parent; /* recipient of SIGCHLD, wait4() reports */ + struct task_struct *real_parent; /* parent process */ /* * children/sibling forms the list of my natural children */ --- PTRACE/include/linux/init_task.h~7_MV_PARENT 2009-05-28 04:12:02.000000000 +0200 +++ PTRACE/include/linux/init_task.h 2009-05-28 08:41:11.000000000 +0200 @@ -139,7 +139,6 @@ extern struct cred init_cred; .ptraced = LIST_HEAD_INIT(tsk.ptraced), \ .ptrace_entry = LIST_HEAD_INIT(tsk.ptrace_entry), \ .real_parent = &tsk, \ - .parent = &tsk, \ .children = LIST_HEAD_INIT(tsk.children), \ .sibling = LIST_HEAD_INIT(tsk.sibling), \ .group_leader = &tsk, \ --- PTRACE/include/linux/ptrace.h~7_MV_PARENT 2009-05-28 08:35:41.000000000 +0200 +++ PTRACE/include/linux/ptrace.h 2009-05-28 08:41:11.000000000 +0200 @@ -76,7 +76,8 @@ #include /* For struct task_struct. */ struct ptrace_context { - unsigned long flags; + unsigned long flags; + struct task_struct *tracer; }; extern int alloc_ptrace_context(struct task_struct *child); @@ -103,11 +104,6 @@ extern int __ptrace_may_access(struct ta /* Returns true on success, false on denial. */ extern bool ptrace_may_access(struct task_struct *task, unsigned int mode); -static inline int ptrace_reparented(struct task_struct *child) -{ - return child->real_parent != child->parent; -} - /** * task_ptrace - return %PT_* flags that apply to a task * @task: pointer to &task_struct in question @@ -123,6 +119,12 @@ static inline int task_ptrace(struct tas task->ptrace_ctx->flags : 0; } +static inline int ptrace_reparented(struct task_struct *child) +{ + return unlikely(task_ptrace(child)) && + child->ptrace_ctx->tracer != child->real_parent; +} + static inline void ptrace_unlink(struct task_struct *child) { if (unlikely(task_ptrace(child))) @@ -167,10 +169,10 @@ static inline void ptrace_init_task(stru { INIT_LIST_HEAD(&child->ptrace_entry); INIT_LIST_HEAD(&child->ptraced); - child->parent = child->real_parent; if (unlikely(child->ptrace_ctx) && task_ptrace(current)) - ptrace_link(child, task_ptrace(current), current->parent); + ptrace_link(child, task_ptrace(current), + current->ptrace_ctx->tracer); } /** --- PTRACE/include/linux/tracehook.h~7_MV_PARENT 2009-05-28 08:19:16.000000000 +0200 +++ PTRACE/include/linux/tracehook.h 2009-05-28 08:41:11.000000000 +0200 @@ -171,8 +171,8 @@ static inline int tracehook_unsafe_exec( */ static inline struct task_struct *tracehook_tracer_task(struct task_struct *tsk) { - if (task_ptrace(tsk) & PT_PTRACED) - return rcu_dereference(tsk->parent); + if (tsk->ptrace_ctx) + return rcu_dereference(tsk->ptrace_ctx->tracer); return NULL; } --- PTRACE/kernel/ptrace.c~7_MV_PARENT 2009-05-28 08:35:41.000000000 +0200 +++ PTRACE/kernel/ptrace.c 2009-05-28 08:41:11.000000000 +0200 @@ -47,7 +47,7 @@ void ptrace_link(struct task_struct *chi BUG_ON(!list_empty(&child->ptrace_entry)); list_add(&child->ptrace_entry, &tracer->ptraced); - child->parent = tracer; + child->ptrace_ctx->tracer = tracer; } /* @@ -85,7 +85,7 @@ void __ptrace_unlink(struct task_struct BUG_ON(!task_ptrace(child)); child->ptrace_ctx->flags = 0; - child->parent = child->real_parent; + child->ptrace_ctx->tracer = NULL; list_del_init(&child->ptrace_entry); arch_ptrace_untrace(child); @@ -108,7 +108,7 @@ int ptrace_check_attach(struct task_stru * be changed by us so it's not changing right after this. */ read_lock(&tasklist_lock); - if (task_ptrace(child) && child->parent == current) { + if (task_ptrace(child) && child->ptrace_ctx->tracer == current) { ret = 0; /* * child->sighand can't be NULL, release_task() @@ -268,7 +268,7 @@ int ptrace_traceme(void) write_lock_irq(&tasklist_lock); /* Are we already being traced? */ if (!task_ptrace(current)) { - ret = security_ptrace_traceme(current->parent); + ret = security_ptrace_traceme(current->real_parent); /* * Check PF_EXITING to ensure ->real_parent has not passed * exit_ptrace(). Otherwise we don't report the error but --- PTRACE/kernel/exit.c~7_MV_PARENT 2009-05-28 04:12:02.000000000 +0200 +++ PTRACE/kernel/exit.c 2009-05-28 08:41:11.000000000 +0200 @@ -336,7 +336,7 @@ static void reparent_to_kthreadd(void) ptrace_unlink(current); /* Reparent to init */ - current->real_parent = current->parent = kthreadd_task; + current->real_parent = kthreadd_task; list_move_tail(¤t->sibling, ¤t->real_parent->children); /* Set the exit signal to SIGCHLD so we signal init on exit */ @@ -780,10 +780,6 @@ static void forget_original_parent(struc list_for_each_entry_safe(p, n, &father->children, sibling) { p->real_parent = reaper; - if (p->parent == father) { - BUG_ON(task_ptrace(p)); - p->parent = p->real_parent; - } reparent_thread(father, p, &dead_children); } write_unlock_irq(&tasklist_lock); --- PTRACE/kernel/signal.c~7_MV_PARENT 2009-05-28 04:14:38.000000000 +0200 +++ PTRACE/kernel/signal.c 2009-05-28 08:43:12.000000000 +0200 @@ -1399,6 +1399,7 @@ int do_notify_parent(struct task_struct { struct siginfo info; unsigned long flags; + struct task_struct *parent; struct sighand_struct *psig; int ret = sig; @@ -1410,6 +1411,11 @@ int do_notify_parent(struct task_struct BUG_ON(!task_ptrace(tsk) && (tsk->group_leader != tsk || !thread_group_empty(tsk))); + if (task_ptrace(tsk)) + parent = tsk->ptrace_ctx->tracer; + else + parent = tsk->real_parent; + info.si_signo = sig; info.si_errno = 0; /* @@ -1425,7 +1431,7 @@ int do_notify_parent(struct task_struct * correct to rely on this */ rcu_read_lock(); - info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns); + info.si_pid = task_pid_nr_ns(tsk, parent->nsproxy->pid_ns); info.si_uid = __task_cred(tsk)->uid; rcu_read_unlock(); @@ -1444,7 +1450,7 @@ int do_notify_parent(struct task_struct info.si_status = tsk->exit_code >> 8; } - psig = tsk->parent->sighand; + psig = parent->sighand; spin_lock_irqsave(&psig->siglock, flags); if (!task_ptrace(tsk) && sig == SIGCHLD && (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN || @@ -1469,8 +1475,8 @@ int do_notify_parent(struct task_struct sig = -1; } if (valid_signal(sig) && sig > 0) - __group_send_sig_info(sig, &info, tsk->parent); - __wake_up_parent(tsk, tsk->parent); + __group_send_sig_info(sig, &info, parent); + __wake_up_parent(tsk, parent); spin_unlock_irqrestore(&psig->siglock, flags); return ret; @@ -1484,7 +1490,7 @@ static void do_notify_parent_cldstop(str struct sighand_struct *sighand; if (task_ptrace(tsk)) - parent = tsk->parent; + parent = tsk->ptrace_ctx->tracer; else { tsk = tsk->group_leader; parent = tsk->real_parent; @@ -1544,7 +1550,7 @@ static inline int may_ptrace_stop(void) * is safe to enter schedule(). */ if (unlikely(current->mm->core_state) && - unlikely(current->mm == current->parent->mm)) + unlikely(current->mm == current->ptrace_ctx->tracer->mm)) return 0; return 1; @@ -1777,7 +1783,7 @@ static int ptrace_signal(int signr, sigi info->si_code = SI_USER; rcu_read_lock(); - tracer = current->parent; + tracer = current->ptrace_ctx->tracer; if (task_ptrace(current)) { info->si_pid = task_pid_vnr(tracer); info->si_uid = task_uid(tracer);