Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758671AbXHQO5v (ORCPT ); Fri, 17 Aug 2007 10:57:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753713AbXHQO5m (ORCPT ); Fri, 17 Aug 2007 10:57:42 -0400 Received: from mailhub.sw.ru ([195.214.233.200]:5600 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752895AbXHQO5l (ORCPT ); Fri, 17 Aug 2007 10:57:41 -0400 Message-ID: <46C5B6AB.6070201@openvz.org> Date: Fri, 17 Aug 2007 18:54:35 +0400 From: Pavel Emelyanov User-Agent: Thunderbird 2.0.0.6 (X11/20070728) MIME-Version: 1.0 To: Oleg Nesterov , Andrew Morton CC: Linux Kernel Mailing List , Sukadev Bhattiprolu , devel@openvz.org Subject: Re: [PATCH] Isolate some explicit usage of task->tgid References: <46C5AD92.70909@openvz.org> <20070817144813.GA347@tv-sign.ru> In-Reply-To: <20070817144813.GA347@tv-sign.ru> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6507 Lines: 199 Oleg Nesterov wrote: > On 08/17, Pavel Emelyanov wrote: >> Actually the p->tgid == pid has to be changed to has_group_leader_pid(), >> but Oleg pointed out that this is the same and thread_group_leader() >> is more preferable. > > No, no, sorry for confusion! I was not clear. I meant that thread_group_leader() > is imho better for posix timers, but Oh! Sorry, new patch is included: From: Pavel Emelyanov With pid namespaces this field is now dangerous to use explicitly, so hide it behind the helpers. Also the pid and pgrp fields o task_struct and signal_struct are to be deprecated. Unfortunately this patch cannot be sent right now as this leads to tons of warnings, so start isolating them, and deprecate later. Actually the p->tgid == pid has to be changed to has_group_leader_pid(), but Oleg pointed out that in case of posix cpu timers this is the same, and thread_group_leader() is more preferable. Signed-off-by: Pavel Emelyanov Acked-by: Oleg Nesterov --- fs/exec.c | 4 ++-- fs/proc/base.c | 2 +- include/linux/sched.h | 6 ++++++ kernel/posix-cpu-timers.c | 12 ++++++------ kernel/posix-timers.c | 4 ++-- kernel/ptrace.c | 2 +- kernel/signal.c | 2 +- mm/oom_kill.c | 2 +- 8 files changed, 20 insertions(+), 14 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index f8cebf8..24b669d 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1691,6 +1691,12 @@ static inline int has_group_leader_pid(s return p->pid == p->tgid; } +static inline +int same_thread_group(struct task_struct *p1, struct task_struct *p2) +{ + return p1->tgid == p2->tgid; +} + static inline struct task_struct *next_thread(const struct task_struct *p) { return list_entry(rcu_dereference(p->thread_group.next), diff --git a/fs/exec.c b/fs/exec.c index 35013f2..796453b 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -865,8 +865,8 @@ static int de_thread(struct task_struct write_lock_irq(&tasklist_lock); - BUG_ON(leader->tgid != tsk->tgid); - BUG_ON(tsk->pid == tsk->tgid); + BUG_ON(!same_thread_group(leader, tsk)); + BUG_ON(has_group_leader_pid(tsk)); /* * An exec() starts a new thread group with the * TGID of the previous thread group. Rehash the diff --git a/fs/proc/base.c b/fs/proc/base.c index e3009ab..6dce57c 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -2474,7 +2474,7 @@ static struct dentry *proc_task_lookup(s rcu_read_unlock(); if (!task) goto out; - if (leader->tgid != task->tgid) + if (!same_thread_group(leader, task)) goto out_drop_task; result = proc_task_instantiate(dir, dentry, task, NULL); diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c index b53c8fc..68c9637 100644 --- a/kernel/posix-cpu-timers.c +++ b/kernel/posix-cpu-timers.c @@ -21,8 +21,8 @@ static int check_clock(const clockid_t w read_lock(&tasklist_lock); p = find_task_by_pid(pid); - if (!p || (CPUCLOCK_PERTHREAD(which_clock) ? - p->tgid != current->tgid : p->tgid != pid)) { + if (!p || !(CPUCLOCK_PERTHREAD(which_clock) ? + same_thread_group(p, current) : thread_group_leader(p))) { error = -EINVAL; } read_unlock(&tasklist_lock); @@ -308,13 +308,13 @@ int posix_cpu_clock_get(const clockid_t p = find_task_by_pid(pid); if (p) { if (CPUCLOCK_PERTHREAD(which_clock)) { - if (p->tgid == current->tgid) { + if (same_thread_group(p, current)) { error = cpu_clock_sample(which_clock, p, &rtn); } } else { read_lock(&tasklist_lock); - if (p->tgid == pid && p->signal) { + if (thread_group_leader(p) && p->signal) { error = cpu_clock_sample_group(which_clock, p, &rtn); @@ -355,7 +355,7 @@ int posix_cpu_timer_create(struct k_itim p = current; } else { p = find_task_by_pid(pid); - if (p && p->tgid != current->tgid) + if (p && !same_thread_group(p, current)) p = NULL; } } else { @@ -363,7 +363,7 @@ int posix_cpu_timer_create(struct k_itim p = current->group_leader; } else { p = find_task_by_pid(pid); - if (p && p->tgid != pid) + if (p && !thread_group_leader(p)) p = NULL; } } diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c index 8d2cb05..bc77ba8 100644 --- a/kernel/posix-timers.c +++ b/kernel/posix-timers.c @@ -404,7 +404,7 @@ static struct task_struct * good_sigeven if ((event->sigev_notify & SIGEV_THREAD_ID ) && (!(rtn = find_task_by_pid(event->sigev_notify_thread_id)) || - rtn->tgid != current->tgid || + !same_thread_group(rtn, current) || (event->sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_SIGNAL)) return NULL; @@ -609,7 +609,7 @@ static struct k_itimer * lock_timer(time spin_unlock(&idr_lock); if ((timr->it_id != timer_id) || !(timr->it_process) || - timr->it_process->tgid != current->tgid) { + !same_thread_group(timr->it_process, current)) { unlock_timer(timr, *flags); timr = NULL; } diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 0d7fd07..f90207a 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -169,7 +169,7 @@ int ptrace_attach(struct task_struct *ta retval = -EPERM; if (task->pid <= 1) goto out; - if (task->tgid == current->tgid) + if (same_thread_group(task, current)) goto out; repeat: diff --git a/kernel/signal.c b/kernel/signal.c index d6ca591..df785a7 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1145,7 +1145,7 @@ static int kill_something_info(int sig, read_lock(&tasklist_lock); for_each_process(p) { - if (p->pid > 1 && p->tgid != current->tgid) { + if (p->pid > 1 && !same_thread_group(p, current)) { int err = group_send_sig_info(sig, info, p); ++count; if (err != -EPERM) diff --git a/mm/oom_kill.c b/mm/oom_kill.c index e276a3c..1a2f687 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -330,7 +330,7 @@ static int oom_kill_task(struct task_str * to memory reserves though, otherwise we might deplete all memory. */ do_each_thread(g, q) { - if (q->mm == mm && q->tgid != p->tgid) + if (q->mm == mm && !same_thread_group(q, p)) force_sig(SIGKILL, q); } while_each_thread(g, q); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/