From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6D7DEC6778A for ; Tue, 24 Jul 2018 03:25:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 24DF520852 for ; Tue, 24 Jul 2018 03:25:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 24DF520852 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=xmission.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388236AbeGXEaA (ORCPT ); Tue, 24 Jul 2018 00:30:00 -0400 Received: from out02.mta.xmission.com ([166.70.13.232]:51280 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388088AbeGXEaA (ORCPT ); Tue, 24 Jul 2018 00:30:00 -0400 Received: from in01.mta.xmission.com ([166.70.13.51]) by out02.mta.xmission.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.87) (envelope-from ) id 1fhnxE-0007VG-5i; Mon, 23 Jul 2018 21:25:40 -0600 Received: from [97.119.167.31] (helo=x220.int.ebiederm.org) by in01.mta.xmission.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.87) (envelope-from ) id 1fhnwy-0008AK-Kz; Mon, 23 Jul 2018 21:25:39 -0600 From: "Eric W. Biederman" To: Linus Torvalds Cc: Oleg Nesterov , Andrew Morton , linux-kernel@vger.kernel.org, Wen Yang , majiang , "Eric W. Biederman" Date: Mon, 23 Jul 2018 22:24:05 -0500 Message-Id: <20180724032419.20231-6-ebiederm@xmission.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <87efft5ncd.fsf_-_@xmission.com> References: <87efft5ncd.fsf_-_@xmission.com> X-XM-SPF: eid=1fhnwy-0008AK-Kz;;;mid=<20180724032419.20231-6-ebiederm@xmission.com>;;;hst=in01.mta.xmission.com;;;ip=97.119.167.31;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX1/NqfuEd6BaDBVpPQkN7E0l4Pi12KaLDPg= X-SA-Exim-Connect-IP: 97.119.167.31 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: [PATCH 06/20] pid: Implement PIDTYPE_TGID X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in01.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Everywhere except in the pid array we distinguish between a tasks pid and a tasks tgid (thread group id). Even in the enumeration we want that distinction sometimes so we have added __PIDTYPE_TGID. With leader_pid we almost have an implementation of PIDTYPE_TGID in struct signal_struct. Add PIDTYPE_TGID as a first class member of the pid_type enumeration and into the pids array. Then remove the __PIDTYPE_TGID special case and the leader_pid in signal_struct. The net size increase is just an extra pointer added to struct pid and an extra pair of pointers of an hlist_node added to task_struct. The effect on code maintenance is the removal of a number of special cases today and the potential to remove many more special cases as PIDTYPE_TGID gets used to it's fullest. The long term potential is allowing zombie thread group leaders to exit, which will remove a lot more special cases in the code. Signed-off-by: "Eric W. Biederman" --- arch/ia64/kernel/asm-offsets.c | 2 +- arch/ia64/kernel/fsys.S | 4 ++-- arch/s390/kernel/perf_cpum_sf.c | 2 +- fs/exec.c | 1 + include/linux/pid.h | 3 +-- include/linux/sched.h | 4 ++-- include/linux/sched/signal.h | 5 ++--- init/init_task.c | 2 +- kernel/events/core.c | 2 +- kernel/exit.c | 1 + kernel/fork.c | 3 ++- kernel/pid.c | 2 -- kernel/time/itimer.c | 5 +++-- kernel/time/posix-cpu-timers.c | 2 +- 14 files changed, 19 insertions(+), 19 deletions(-) diff --git a/arch/ia64/kernel/asm-offsets.c b/arch/ia64/kernel/asm-offsets.c index c1f8a57855af..00e8e2a1eb19 100644 --- a/arch/ia64/kernel/asm-offsets.c +++ b/arch/ia64/kernel/asm-offsets.c @@ -67,7 +67,7 @@ void foo(void) DEFINE(IA64_SIGNAL_GROUP_STOP_COUNT_OFFSET,offsetof (struct signal_struct, group_stop_count)); DEFINE(IA64_SIGNAL_SHARED_PENDING_OFFSET,offsetof (struct signal_struct, shared_pending)); - DEFINE(IA64_SIGNAL_LEADER_PID_OFFSET, offsetof (struct signal_struct, leader_pid)); + DEFINE(IA64_SIGNAL_PIDS_TGID_OFFSET, offsetof (struct signal_struct, pids[PIDTYPE_TGID])); BLANK(); diff --git a/arch/ia64/kernel/fsys.S b/arch/ia64/kernel/fsys.S index e85ebdac678b..d80c99a5f55d 100644 --- a/arch/ia64/kernel/fsys.S +++ b/arch/ia64/kernel/fsys.S @@ -68,10 +68,10 @@ ENTRY(fsys_getpid) add r9=TI_FLAGS+IA64_TASK_SIZE,r16 ;; ld4 r9=[r9] - add r17=IA64_SIGNAL_LEADER_PID_OFFSET,r17 + add r17=IA64_SIGNAL_PIDS_TGID_OFFSET,r17 ;; and r9=TIF_ALLWORK_MASK,r9 - ld8 r17=[r17] // r17 = current->signal->leader_pid + ld8 r17=[r17] // r17 = current->signal->pids[PIDTYPE_TGID] ;; add r8=IA64_PID_LEVEL_OFFSET,r17 ;; diff --git a/arch/s390/kernel/perf_cpum_sf.c b/arch/s390/kernel/perf_cpum_sf.c index 0292d68e7dde..ca0b7ae894bb 100644 --- a/arch/s390/kernel/perf_cpum_sf.c +++ b/arch/s390/kernel/perf_cpum_sf.c @@ -665,7 +665,7 @@ static void cpumsf_output_event_pid(struct perf_event *event, goto out; /* Update the process ID (see also kernel/events/core.c) */ - data->tid_entry.pid = cpumsf_pid_type(event, pid, __PIDTYPE_TGID); + data->tid_entry.pid = cpumsf_pid_type(event, pid, PIDTYPE_TGID); data->tid_entry.tid = cpumsf_pid_type(event, pid, PIDTYPE_PID); perf_output_sample(&handle, &header, data, event); diff --git a/fs/exec.c b/fs/exec.c index 2d4e0075bd24..79a11fbded7a 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1146,6 +1146,7 @@ static int de_thread(struct task_struct *tsk) */ tsk->pid = leader->pid; change_pid(tsk, PIDTYPE_PID, task_pid(leader)); + transfer_pid(leader, tsk, PIDTYPE_TGID); transfer_pid(leader, tsk, PIDTYPE_PGID); transfer_pid(leader, tsk, PIDTYPE_SID); diff --git a/include/linux/pid.h b/include/linux/pid.h index 3d4c504dcc8c..14a9a39da9c7 100644 --- a/include/linux/pid.h +++ b/include/linux/pid.h @@ -7,11 +7,10 @@ enum pid_type { PIDTYPE_PID, + PIDTYPE_TGID, PIDTYPE_PGID, PIDTYPE_SID, PIDTYPE_MAX, - /* only valid to __task_pid_nr_ns() */ - __PIDTYPE_TGID }; /* diff --git a/include/linux/sched.h b/include/linux/sched.h index 445bdf5b1f64..06b4e3bda93a 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1275,12 +1275,12 @@ static inline pid_t task_session_vnr(struct task_struct *tsk) static inline pid_t task_tgid_nr_ns(struct task_struct *tsk, struct pid_namespace *ns) { - return __task_pid_nr_ns(tsk, __PIDTYPE_TGID, ns); + return __task_pid_nr_ns(tsk, PIDTYPE_TGID, ns); } static inline pid_t task_tgid_vnr(struct task_struct *tsk) { - return __task_pid_nr_ns(tsk, __PIDTYPE_TGID, NULL); + return __task_pid_nr_ns(tsk, PIDTYPE_TGID, NULL); } static inline pid_t task_ppid_nr_ns(const struct task_struct *tsk, struct pid_namespace *ns) diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h index 2dcded16eb1e..ee30a5ba475f 100644 --- a/include/linux/sched/signal.h +++ b/include/linux/sched/signal.h @@ -147,7 +147,6 @@ struct signal_struct { #endif /* PID/PID hash table linkage. */ - struct pid *leader_pid; struct pid *pids[PIDTYPE_MAX]; #ifdef CONFIG_NO_HZ_FULL @@ -571,7 +570,7 @@ struct pid *task_pid_type(struct task_struct *task, enum pid_type type) static inline struct pid *task_tgid(struct task_struct *task) { - return task->signal->leader_pid; + return task->signal->pids[PIDTYPE_TGID]; } /* @@ -607,7 +606,7 @@ static inline bool thread_group_leader(struct task_struct *p) */ static inline bool has_group_leader_pid(struct task_struct *p) { - return task_pid(p) == p->signal->leader_pid; + return task_pid(p) == task_tgid(p); } static inline diff --git a/init/init_task.c b/init/init_task.c index db12a61259f1..4f97846256d7 100644 --- a/init/init_task.c +++ b/init/init_task.c @@ -33,9 +33,9 @@ static struct signal_struct init_signals = { }, #endif INIT_CPU_TIMERS(init_signals) - .leader_pid = &init_struct_pid, .pids = { [PIDTYPE_PID] = &init_struct_pid, + [PIDTYPE_TGID] = &init_struct_pid, [PIDTYPE_PGID] = &init_struct_pid, [PIDTYPE_SID] = &init_struct_pid, }, diff --git a/kernel/events/core.c b/kernel/events/core.c index 80cca2b30c4f..9025b1796ca8 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -1334,7 +1334,7 @@ static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p, static u32 perf_event_pid(struct perf_event *event, struct task_struct *p) { - return perf_event_pid_type(event, p, __PIDTYPE_TGID); + return perf_event_pid_type(event, p, PIDTYPE_TGID); } static u32 perf_event_tid(struct perf_event *event, struct task_struct *p) diff --git a/kernel/exit.c b/kernel/exit.c index 16432428fc6c..25582b442955 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -73,6 +73,7 @@ static void __unhash_process(struct task_struct *p, bool group_dead) nr_threads--; detach_pid(p, PIDTYPE_PID); if (group_dead) { + detach_pid(p, PIDTYPE_TGID); detach_pid(p, PIDTYPE_PGID); detach_pid(p, PIDTYPE_SID); diff --git a/kernel/fork.c b/kernel/fork.c index d2952162399b..cc5be0d01ce6 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1946,6 +1946,7 @@ static __latent_entropy struct task_struct *copy_process( init_task_pid(p, PIDTYPE_PID, pid); if (thread_group_leader(p)) { + init_task_pid(p, PIDTYPE_TGID, pid); init_task_pid(p, PIDTYPE_PGID, task_pgrp(current)); init_task_pid(p, PIDTYPE_SID, task_session(current)); @@ -1954,7 +1955,6 @@ static __latent_entropy struct task_struct *copy_process( p->signal->flags |= SIGNAL_UNKILLABLE; } - p->signal->leader_pid = pid; p->signal->tty = tty_kref_get(current->signal->tty); /* * Inherit has_child_subreaper flag under the same @@ -1965,6 +1965,7 @@ static __latent_entropy struct task_struct *copy_process( p->real_parent->signal->is_child_subreaper; list_add_tail(&p->sibling, &p->real_parent->children); list_add_tail_rcu(&p->tasks, &init_task.tasks); + attach_pid(p, PIDTYPE_TGID); attach_pid(p, PIDTYPE_PGID); attach_pid(p, PIDTYPE_SID); __this_cpu_inc(process_counts); diff --git a/kernel/pid.c b/kernel/pid.c index f8486d2e2346..de1cfc4f75a2 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -269,8 +269,6 @@ static struct pid **task_pid_ptr(struct task_struct *task, enum pid_type type) { return (type == PIDTYPE_PID) ? &task->thread_pid : - (type == __PIDTYPE_TGID) ? - &task->signal->leader_pid : &task->signal->pids[type]; } diff --git a/kernel/time/itimer.c b/kernel/time/itimer.c index f26acef5d7b4..9a65713c8309 100644 --- a/kernel/time/itimer.c +++ b/kernel/time/itimer.c @@ -139,9 +139,10 @@ enum hrtimer_restart it_real_fn(struct hrtimer *timer) { struct signal_struct *sig = container_of(timer, struct signal_struct, real_timer); + struct pid *leader_pid = sig->pids[PIDTYPE_TGID]; - trace_itimer_expire(ITIMER_REAL, sig->leader_pid, 0); - kill_pid_info(SIGALRM, SEND_SIG_PRIV, sig->leader_pid); + trace_itimer_expire(ITIMER_REAL, leader_pid, 0); + kill_pid_info(SIGALRM, SEND_SIG_PRIV, leader_pid); return HRTIMER_NORESTART; } diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c index 5a6251ac6f7a..40e6fae46cec 100644 --- a/kernel/time/posix-cpu-timers.c +++ b/kernel/time/posix-cpu-timers.c @@ -895,7 +895,7 @@ static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it, trace_itimer_expire(signo == SIGPROF ? ITIMER_PROF : ITIMER_VIRTUAL, - tsk->signal->leader_pid, cur_time); + task_tgid(tsk), cur_time); __group_send_sig_info(signo, SEND_SIG_PRIV, tsk); } -- 2.17.1