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Diffstat (limited to 'kernel/fork.c')
-rw-r--r--kernel/fork.c75
1 files changed, 54 insertions, 21 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index 5ee74c113381..ff5037be7771 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1487,6 +1487,7 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
init_waitqueue_head(&sig->wait_chldexit);
sig->curr_target = tsk;
init_sigpending(&sig->shared_pending);
+ INIT_HLIST_HEAD(&sig->multiprocess);
seqlock_init(&sig->stats_lock);
prev_cputime_init(&sig->prev_cputime);
@@ -1580,10 +1581,22 @@ static void posix_cpu_timers_init(struct task_struct *tsk)
static inline void posix_cpu_timers_init(struct task_struct *tsk) { }
#endif
+static inline void init_task_pid_links(struct task_struct *task)
+{
+ enum pid_type type;
+
+ for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type) {
+ INIT_HLIST_NODE(&task->pid_links[type]);
+ }
+}
+
static inline void
init_task_pid(struct task_struct *task, enum pid_type type, struct pid *pid)
{
- task->pids[type].pid = pid;
+ if (type == PIDTYPE_PID)
+ task->thread_pid = pid;
+ else
+ task->signal->pids[type] = pid;
}
static inline void rcu_copy_process(struct task_struct *p)
@@ -1621,6 +1634,7 @@ static __latent_entropy struct task_struct *copy_process(
{
int retval;
struct task_struct *p;
+ struct multiprocess_signals delayed;
/*
* Don't allow sharing the root directory with processes in a different
@@ -1668,6 +1682,24 @@ static __latent_entropy struct task_struct *copy_process(
return ERR_PTR(-EINVAL);
}
+ /*
+ * Force any signals received before this point to be delivered
+ * before the fork happens. Collect up signals sent to multiple
+ * processes that happen during the fork and delay them so that
+ * they appear to happen after the fork.
+ */
+ sigemptyset(&delayed.signal);
+ INIT_HLIST_NODE(&delayed.node);
+
+ spin_lock_irq(&current->sighand->siglock);
+ if (!(clone_flags & CLONE_THREAD))
+ hlist_add_head(&delayed.node, &current->signal->multiprocess);
+ recalc_sigpending();
+ spin_unlock_irq(&current->sighand->siglock);
+ retval = -ERESTARTNOINTR;
+ if (signal_pending(current))
+ goto fork_out;
+
retval = -ENOMEM;
p = dup_task_struct(current, node);
if (!p)
@@ -1941,29 +1973,26 @@ static __latent_entropy struct task_struct *copy_process(
rseq_fork(p, clone_flags);
- /*
- * Process group and session signals need to be delivered to just the
- * parent before the fork or both the parent and the child after the
- * fork. Restart if a signal comes in before we add the new process to
- * it's process group.
- * A fatal signal pending means that current will exit, so the new
- * thread can't slip out of an OOM kill (or normal SIGKILL).
- */
- recalc_sigpending();
- if (signal_pending(current)) {
- retval = -ERESTARTNOINTR;
- goto bad_fork_cancel_cgroup;
- }
+ /* Don't start children in a dying pid namespace */
if (unlikely(!(ns_of_pid(pid)->pid_allocated & PIDNS_ADDING))) {
retval = -ENOMEM;
goto bad_fork_cancel_cgroup;
}
+ /* Let kill terminate clone/fork in the middle */
+ if (fatal_signal_pending(current)) {
+ retval = -EINTR;
+ goto bad_fork_cancel_cgroup;
+ }
+
+
+ init_task_pid_links(p);
if (likely(p->pid)) {
ptrace_init_task(p, (clone_flags & CLONE_PTRACE) || trace);
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));
@@ -1971,8 +2000,7 @@ static __latent_entropy struct task_struct *copy_process(
ns_of_pid(pid)->child_reaper = p;
p->signal->flags |= SIGNAL_UNKILLABLE;
}
-
- p->signal->leader_pid = pid;
+ p->signal->shared_pending.signal = delayed.signal;
p->signal->tty = tty_kref_get(current->signal->tty);
/*
* Inherit has_child_subreaper flag under the same
@@ -1983,6 +2011,7 @@ 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);
@@ -1990,6 +2019,7 @@ static __latent_entropy struct task_struct *copy_process(
current->signal->nr_threads++;
atomic_inc(&current->signal->live);
atomic_inc(&current->signal->sigcnt);
+ task_join_group_stop(p);
list_add_tail_rcu(&p->thread_group,
&p->group_leader->thread_group);
list_add_tail_rcu(&p->thread_node,
@@ -1998,8 +2028,8 @@ static __latent_entropy struct task_struct *copy_process(
attach_pid(p, PIDTYPE_PID);
nr_threads++;
}
-
total_forks++;
+ hlist_del_init(&delayed.node);
spin_unlock(&current->sighand->siglock);
syscall_tracepoint_update(p);
write_unlock_irq(&tasklist_lock);
@@ -2064,16 +2094,19 @@ bad_fork_free:
put_task_stack(p);
free_task(p);
fork_out:
+ spin_lock_irq(&current->sighand->siglock);
+ hlist_del_init(&delayed.node);
+ spin_unlock_irq(&current->sighand->siglock);
return ERR_PTR(retval);
}
-static inline void init_idle_pids(struct pid_link *links)
+static inline void init_idle_pids(struct task_struct *idle)
{
enum pid_type type;
for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type) {
- INIT_HLIST_NODE(&links[type].node); /* not really needed */
- links[type].pid = &init_struct_pid;
+ INIT_HLIST_NODE(&idle->pid_links[type]); /* not really needed */
+ init_task_pid(idle, type, &init_struct_pid);
}
}
@@ -2083,7 +2116,7 @@ struct task_struct *fork_idle(int cpu)
task = copy_process(CLONE_VM, 0, 0, NULL, &init_struct_pid, 0, 0,
cpu_to_node(cpu));
if (!IS_ERR(task)) {
- init_idle_pids(task->pids);
+ init_idle_pids(task);
init_idle(task, cpu);
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-16 11:36:09 +0000