The patch titled
Isolate some explicit usage of task->tgid
has been added to the -mm tree. Its filename is
isolate-some-explicit-usage-of-task-tgid.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: Isolate some explicit usage of task->tgid
From: Pavel Emelyanov <xemul@xxxxxxxxxx>
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 <xemul@xxxxxxxxxx>
Acked-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Sukadev Bhattiprolu <sukadev@xxxxxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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 -puN fs/exec.c~isolate-some-explicit-usage-of-task-tgid fs/exec.c
--- a/fs/exec.c~isolate-some-explicit-usage-of-task-tgid
+++ a/fs/exec.c
@@ -858,8 +858,8 @@ 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 -puN fs/proc/base.c~isolate-some-explicit-usage-of-task-tgid fs/proc/base.c
--- a/fs/proc/base.c~isolate-some-explicit-usage-of-task-tgid
+++ a/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 -puN include/linux/sched.h~isolate-some-explicit-usage-of-task-tgid include/linux/sched.h
--- a/include/linux/sched.h~isolate-some-explicit-usage-of-task-tgid
+++ a/include/linux/sched.h
@@ -1684,6 +1684,12 @@ 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 -puN kernel/posix-cpu-timers.c~isolate-some-explicit-usage-of-task-tgid kernel/posix-cpu-timers.c
--- a/kernel/posix-cpu-timers.c~isolate-some-explicit-usage-of-task-tgid
+++ a/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 -puN kernel/posix-timers.c~isolate-some-explicit-usage-of-task-tgid kernel/posix-timers.c
--- a/kernel/posix-timers.c~isolate-some-explicit-usage-of-task-tgid
+++ a/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;
@@ -608,7 +608,7 @@ static struct k_itimer * lock_timer(time
spin_lock(&timr->it_lock);
if ((timr->it_id != timer_id) || !(timr->it_process) ||
- timr->it_process->tgid != current->tgid) {
+ !same_thread_group(timr->it_process, current)) {
spin_unlock(&timr->it_lock);
spin_unlock_irqrestore(&idr_lock, *flags);
timr = NULL;
diff -puN kernel/ptrace.c~isolate-some-explicit-usage-of-task-tgid kernel/ptrace.c
--- a/kernel/ptrace.c~isolate-some-explicit-usage-of-task-tgid
+++ a/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 -puN kernel/signal.c~isolate-some-explicit-usage-of-task-tgid kernel/signal.c
--- a/kernel/signal.c~isolate-some-explicit-usage-of-task-tgid
+++ a/kernel/signal.c
@@ -1155,7 +1155,7 @@ 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 -puN mm/oom_kill.c~isolate-some-explicit-usage-of-task-tgid mm/oom_kill.c
--- a/mm/oom_kill.c~isolate-some-explicit-usage-of-task-tgid
+++ a/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);
_
Patches currently in -mm which might be from xemul@xxxxxxxxxx are
git-net.patch
pid-namespaces-round-up-the-api.patch
pid-namespaces-make-get_pid_ns-return-the-namespace-itself.patch
pid-namespaces-dynamic-kmem-cache-allocator-for-pid-namespaces.patch
pid-namespaces-dynamic-kmem-cache-allocator-for-pid-namespaces-fix.patch
pid-namespaces-define-and-use-task_active_pid_ns-wrapper.patch
pid-namespaces-rename-child_reaper-function.patch
pid-namespaces-use-task_pid-to-find-leaders-pid.patch
pid-namespaces-define-is_global_init-and-is_container_init.patch
pid-namespaces-move-alloc_pid-to-copy_process.patch
make-access-to-tasks-nsproxy-lighter.patch
pid-namespaces-rework-forget_original_parent.patch
pid-namespaces-move-exit_task_namespaces.patch
pid-namespaces-introduce-ms_kernmount-flag.patch
pid-namespaces-prepare-proc_flust_task-to-flush-entries-from-multiple-proc-trees.patch
pid-namespaces-introduce-struct-upid.patch
pid-namespaces-add-support-for-pid-namespaces-hierarchy.patch
pid-namespaces-make-alloc_pid-free_pid-and-put_pid-work-with-struct-upid.patch
pid-namespaces-helpers-to-obtain-pid-numbers.patch
pid-namespaces-helpers-to-find-the-task-by-its-numerical-ids.patch
pid-namespaces-move-alloc_pid-lower-in-copy_process.patch
pid-namespaces-make-proc-have-multiple-superblocks-one-for-each-namespace.patch
pid-namespaces-miscelaneous-preparations-for-pid-namespaces.patch
pid-namespaces-allow-cloning-of-new-namespace.patch
pid-namespaces-allow-cloning-of-new-namespace-fix-check-for-return-value-of-create_pid_namespace.patch
pid-namespaces-make-proc_flush_task-actually-from-entries-from-multiple-namespaces.patch
pid-namespaces-initialize-the-namespaces-proc_mnt.patch
pid-namespaces-allow-signalling-container-init.patch
pid-namespaces-destroy-pid-namespace-on-inits-death.patch
pid-namespaces-changes-to-show-virtual-ids-to-user.patch
pid-namespaces-changes-to-show-virtual-ids-to-user-fix-the-return-value-of-sys_set_tid_address.patch
pid-namespaces-changes-to-show-virtual-ids-to-user-use-find_task_by_pid_ns-in-places-that-operate-with-virtual.patch
pid-namespaces-remove-the-struct-pid-unneeded-fields.patch
isolate-some-explicit-usage-of-task-tgid.patch
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