From: "Eric W. Biederman" <ebiederm@xmission.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, Wen Yang <wen.yang99@zte.com.cn>,
majiang <ma.jiang@zte.com.cn>,
"Eric W. Biederman" <ebiederm@xmission.com>
Subject: [PATCH 06/20] pid: Implement PIDTYPE_TGID
Date: Mon, 23 Jul 2018 22:24:05 -0500 [thread overview]
Message-ID: <20180724032419.20231-6-ebiederm@xmission.com> (raw)
In-Reply-To: <87efft5ncd.fsf_-_@xmission.com>
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" <ebiederm@xmission.com>
---
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
next prev parent reply other threads:[~2018-07-24 3:25 UTC|newest]
Thread overview: 96+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <bug-200447-5873-b2kAsSyE1X@https.bugzilla.kernel.org/>
[not found] ` <CA+55aFyOaEGc_wjRuAxYZH7D4zi4xUQTqUwMmUzxFJQ__2pXuQ@mail.gmail.com>
[not found] ` <87h8l9p7bg.fsf@xmission.com>
[not found] ` <20180709104158.GA23796@redhat.com>
[not found] ` <87sh4so5jv.fsf@xmission.com>
[not found] ` <20180709145726.GA26149@redhat.com>
[not found] ` <877em4nxo0.fsf@xmission.com>
[not found] ` <CA+55aFwq90_KeRUesktap7L_4Hp3gatKZ28RYw1jXBYeOqUoeA@mail.gmail.com>
[not found] ` <87lgakm4ol.fsf@xmission.com>
[not found] ` <CA+55aFz1XFvOgJySKVNQD9VS4hys0J7rozxqd3s5ND0z80tfVw@mail.gmail.com>
[not found] ` <20180710134639.GA2453@redhat.com>
2018-07-10 16:00 ` [Bug 200447] infinite loop in fork syscall Eric W. Biederman
2018-07-11 12:08 ` Oleg Nesterov
[not found] ` <CA+55aFxcjSYAj-CZFEuDwiwZyMg+prV_jeP_Vuh06RJA0BboSw@mail.gmail.com>
2018-07-11 2:41 ` [RFC][PATCH 0/11] PIDTYPE_TGID and fewer fork restarts Eric W. Biederman
2018-07-11 2:44 ` [RFC][PATCH 01/11] pids: Initialize leader_pid in init_task Eric W. Biederman
2018-07-11 2:44 ` [RFC][PATCH 02/11] pids: Move task_pid_type into sched/signal.h Eric W. Biederman
2018-07-11 2:44 ` [RFC][PATCH 03/11] pids: Compute task_tgid using signal->leader_pid Eric W. Biederman
2018-07-11 2:44 ` [RFC][PATCH 04/11] kvm: Don't open code task_pid in kvm_vcpu_ioctl Eric W. Biederman
2018-07-11 2:44 ` [RFC][PATCH 05/11] pids: Move the pgrp and session pid pointers from task_struct to signal_struct Eric W. Biederman
2018-07-17 11:59 ` Oleg Nesterov
2018-07-11 2:44 ` [RFC][PATCH 06/11] pid: Implement PIDTYPE_TGID Eric W. Biederman
2018-07-11 2:44 ` [RFC][PATCH 07/11] signal: Deliver group signals via PIDTYPE_TGID not PIDTYPE_PID Eric W. Biederman
2018-07-16 12:51 ` Oleg Nesterov
2018-07-16 14:50 ` Eric W. Biederman
2018-07-16 17:17 ` Linus Torvalds
2018-07-16 18:01 ` Eric W. Biederman
2018-07-16 18:40 ` Linus Torvalds
2018-07-17 9:56 ` Oleg Nesterov
2018-07-17 10:18 ` Oleg Nesterov
2018-07-20 23:41 ` Eric W. Biederman
2018-07-17 16:38 ` Linus Torvalds
2018-07-20 23:27 ` Eric W. Biederman
2018-07-11 2:44 ` [RFC][PATCH 08/11] signal: Use PIDTYPE_TGID to clearly store where file signals will be sent Eric W. Biederman
2018-07-11 2:44 ` [RFC][PATCH 09/11] tty_io: Use do_send_sig_info in __do_SACK to forcibly kill tasks Eric W. Biederman
2018-07-16 14:55 ` Oleg Nesterov
2018-07-16 15:08 ` Eric W. Biederman
2018-07-16 16:50 ` Linus Torvalds
2018-07-16 19:17 ` Eric W. Biederman
2018-07-16 19:36 ` Linus Torvalds
2018-07-17 1:48 ` Eric W. Biederman
2018-07-17 10:58 ` Oleg Nesterov
2018-07-11 2:44 ` [RFC][PATCH 10/11] signal: Push pid type from signal senders down into __send_signal Eric W. Biederman
2018-07-11 3:11 ` Linus Torvalds
2018-07-11 2:44 ` [RFC][PATCH 11/11] signal: Ignore all but multi-process signals that come in during fork Eric W. Biederman
2018-07-11 14:14 ` Oleg Nesterov
2018-07-11 16:02 ` Eric W. Biederman
2018-07-12 13:42 ` Oleg Nesterov
2018-07-12 17:11 ` Eric W. Biederman
2018-07-13 14:51 ` Eric W. Biederman
2018-07-24 3:22 ` [PATCH 00/20] PIDTYPE_TGID removal of fork restarts Eric W. Biederman
2018-07-24 3:24 ` [PATCH 01/20] pids: Initialize leader_pid in init_task Eric W. Biederman
2018-07-24 3:24 ` [PATCH 02/20] pids: Move task_pid_type into sched/signal.h Eric W. Biederman
2018-07-24 3:24 ` [PATCH 03/20] pids: Compute task_tgid using signal->leader_pid Eric W. Biederman
2018-07-24 3:24 ` [PATCH 04/20] kvm: Don't open code task_pid in kvm_vcpu_ioctl Eric W. Biederman
2018-07-24 3:24 ` [PATCH 05/20] pids: Move the pgrp and session pid pointers from task_struct to signal_struct Eric W. Biederman
2018-07-24 3:24 ` Eric W. Biederman [this message]
2018-07-24 3:24 ` [PATCH 07/20] signal: Use PIDTYPE_TGID to clearly store where file signals will be sent Eric W. Biederman
2018-08-16 4:04 ` [PATCH] signal: Don't send signals to tasks that don't exist Eric W. Biederman
2018-08-17 17:34 ` Dmitry Vyukov
2018-08-17 18:46 ` Eric W. Biederman
2018-08-17 19:24 ` Andrew Morton
2018-08-18 5:51 ` Eric W. Biederman
2018-08-20 19:26 ` J. Bruce Fields
2018-07-24 3:24 ` [PATCH 08/20] posix-timers: Noralize good_sigevent Eric W. Biederman
2018-07-24 3:24 ` [PATCH 09/20] signal: Pass pid and pid type into send_sigqueue Eric W. Biederman
2018-07-24 3:24 ` [PATCH 10/20] signal: Pass pid type into group_send_sig_info Eric W. Biederman
2018-07-24 3:24 ` [PATCH 11/20] signal: Pass pid type into send_sigio_to_task & send_sigurg_to_task Eric W. Biederman
2018-07-24 3:24 ` [PATCH 12/20] signal: Pass pid type into do_send_sig_info Eric W. Biederman
2018-07-24 3:24 ` [PATCH 13/20] signal: Push pid type down into send_signal Eric W. Biederman
2018-07-24 3:24 ` [PATCH 14/20] signal: Push pid type down into __send_signal Eric W. Biederman
2018-07-24 3:24 ` [PATCH 15/20] signal: Push pid type down into complete_signal Eric W. Biederman
2018-07-24 3:24 ` [PATCH 16/20] fork: Move and describe why the code examines PIDNS_ADDING Eric W. Biederman
2018-07-24 3:24 ` [PATCH 17/20] fork: Unconditionally exit if a fatal signal is pending Eric W. Biederman
2018-07-24 3:24 ` [PATCH 18/20] signal: Add calculate_sigpending() Eric W. Biederman
2018-07-26 13:20 ` Oleg Nesterov
2018-07-26 15:13 ` Eric W. Biederman
2018-07-26 16:24 ` Oleg Nesterov
2018-07-24 3:24 ` [PATCH 19/20] fork: Have new threads join on-going signal group stops Eric W. Biederman
2018-07-24 3:24 ` [PATCH 20/20] signal: Don't restart fork when signals come in Eric W. Biederman
2018-07-24 17:27 ` Linus Torvalds
2018-07-24 17:58 ` Eric W. Biederman
2018-07-24 18:29 ` Linus Torvalds
2018-07-24 20:05 ` Eric W. Biederman
2018-07-24 20:15 ` Linus Torvalds
2018-07-24 20:40 ` [PATCH v2 " Eric W. Biederman
2018-07-24 20:56 ` Linus Torvalds
2018-07-24 21:24 ` Eric W. Biederman
2018-07-25 3:56 ` [PATCH v3 " Eric W. Biederman
2018-07-26 13:41 ` Oleg Nesterov
2018-07-26 14:42 ` Eric W. Biederman
2018-07-26 15:55 ` Oleg Nesterov
2018-08-09 6:19 ` Eric W. Biederman
2018-07-26 16:21 ` Oleg Nesterov
2018-07-24 17:29 ` [PATCH 00/20] PIDTYPE_TGID removal of fork restarts Linus Torvalds
2018-07-25 16:05 ` Oleg Nesterov
2018-07-25 16:58 ` Eric W. Biederman
2018-08-09 6:53 ` [PATCH v5 0/6] Not restarting for due to signals Eric W. Biederman
2018-08-09 6:56 ` [PATCH v5 1/6] fork: Move and describe why the code examines PIDNS_ADDING Eric W. Biederman
2018-08-09 6:56 ` [PATCH v5 2/6] fork: Unconditionally exit if a fatal signal is pending Eric W. Biederman
2018-08-09 6:56 ` [PATCH v5 3/6] signal: Add calculate_sigpending() Eric W. Biederman
2018-08-09 6:56 ` [PATCH v5 4/6] fork: Skip setting TIF_SIGPENDING in ptrace_init_task Eric W. Biederman
2018-08-09 6:56 ` [PATCH v5 5/6] fork: Have new threads join on-going signal group stops Eric W. Biederman
2018-08-09 6:56 ` [PATCH v5 6/6] signal: Don't restart fork when signals come in Eric W. Biederman
2018-08-09 17:15 ` Linus Torvalds
2018-08-09 17:42 ` Eric W. Biederman
2018-08-09 18:09 ` [PATCH v6 " Eric W. Biederman
2018-08-09 17:16 ` [PATCH v5 0/6] Not restarting for due to signals Linus Torvalds
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