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-rw-r--r--kernel/exit.c148
1 files changed, 97 insertions, 51 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index 531aadca5530..bc0ec674d3f4 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -29,8 +29,11 @@
#include <linux/cpuset.h>
#include <linux/syscalls.h>
#include <linux/signal.h>
+#include <linux/posix-timers.h>
#include <linux/cn_proc.h>
#include <linux/mutex.h>
+#include <linux/futex.h>
+#include <linux/compat.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
@@ -48,15 +51,80 @@ static void __unhash_process(struct task_struct *p)
{
nr_threads--;
detach_pid(p, PIDTYPE_PID);
- detach_pid(p, PIDTYPE_TGID);
if (thread_group_leader(p)) {
detach_pid(p, PIDTYPE_PGID);
detach_pid(p, PIDTYPE_SID);
- if (p->pid)
- __get_cpu_var(process_counts)--;
+
+ list_del_init(&p->tasks);
+ __get_cpu_var(process_counts)--;
}
+ list_del_rcu(&p->thread_group);
+ remove_parent(p);
+}
+
+/*
+ * This function expects the tasklist_lock write-locked.
+ */
+static void __exit_signal(struct task_struct *tsk)
+{
+ struct signal_struct *sig = tsk->signal;
+ struct sighand_struct *sighand;
+
+ BUG_ON(!sig);
+ BUG_ON(!atomic_read(&sig->count));
+
+ rcu_read_lock();
+ sighand = rcu_dereference(tsk->sighand);
+ spin_lock(&sighand->siglock);
- REMOVE_LINKS(p);
+ posix_cpu_timers_exit(tsk);
+ if (atomic_dec_and_test(&sig->count))
+ posix_cpu_timers_exit_group(tsk);
+ else {
+ /*
+ * If there is any task waiting for the group exit
+ * then notify it:
+ */
+ if (sig->group_exit_task && atomic_read(&sig->count) == sig->notify_count) {
+ wake_up_process(sig->group_exit_task);
+ sig->group_exit_task = NULL;
+ }
+ if (tsk == sig->curr_target)
+ sig->curr_target = next_thread(tsk);
+ /*
+ * Accumulate here the counters for all threads but the
+ * group leader as they die, so they can be added into
+ * the process-wide totals when those are taken.
+ * The group leader stays around as a zombie as long
+ * as there are other threads. When it gets reaped,
+ * the exit.c code will add its counts into these totals.
+ * We won't ever get here for the group leader, since it
+ * will have been the last reference on the signal_struct.
+ */
+ sig->utime = cputime_add(sig->utime, tsk->utime);
+ sig->stime = cputime_add(sig->stime, tsk->stime);
+ sig->min_flt += tsk->min_flt;
+ sig->maj_flt += tsk->maj_flt;
+ sig->nvcsw += tsk->nvcsw;
+ sig->nivcsw += tsk->nivcsw;
+ sig->sched_time += tsk->sched_time;
+ sig = NULL; /* Marker for below. */
+ }
+
+ __unhash_process(tsk);
+
+ tsk->signal = NULL;
+ tsk->sighand = NULL;
+ spin_unlock(&sighand->siglock);
+ rcu_read_unlock();
+
+ __cleanup_sighand(sighand);
+ clear_tsk_thread_flag(tsk,TIF_SIGPENDING);
+ flush_sigqueue(&tsk->pending);
+ if (sig) {
+ flush_sigqueue(&sig->shared_pending);
+ __cleanup_signal(sig);
+ }
}
void release_task(struct task_struct * p)
@@ -65,21 +133,14 @@ void release_task(struct task_struct * p)
task_t *leader;
struct dentry *proc_dentry;
-repeat:
+repeat:
atomic_dec(&p->user->processes);
spin_lock(&p->proc_lock);
proc_dentry = proc_pid_unhash(p);
write_lock_irq(&tasklist_lock);
- if (unlikely(p->ptrace))
- __ptrace_unlink(p);
+ ptrace_unlink(p);
BUG_ON(!list_empty(&p->ptrace_list) || !list_empty(&p->ptrace_children));
__exit_signal(p);
- /*
- * Note that the fastpath in sys_times depends on __exit_signal having
- * updated the counters before a task is removed from the tasklist of
- * the process by __unhash_process.
- */
- __unhash_process(p);
/*
* If we are the last non-leader member of the thread
@@ -114,21 +175,6 @@ repeat:
goto repeat;
}
-/* we are using it only for SMP init */
-
-void unhash_process(struct task_struct *p)
-{
- struct dentry *proc_dentry;
-
- spin_lock(&p->proc_lock);
- proc_dentry = proc_pid_unhash(p);
- write_lock_irq(&tasklist_lock);
- __unhash_process(p);
- write_unlock_irq(&tasklist_lock);
- spin_unlock(&p->proc_lock);
- proc_pid_flush(proc_dentry);
-}
-
/*
* This checks not only the pgrp, but falls back on the pid if no
* satisfactory pgrp is found. I dunno - gdb doesn't work correctly
@@ -236,10 +282,10 @@ static void reparent_to_init(void)
ptrace_unlink(current);
/* Reparent to init */
- REMOVE_LINKS(current);
+ remove_parent(current);
current->parent = child_reaper;
current->real_parent = child_reaper;
- SET_LINKS(current);
+ add_parent(current);
/* Set the exit signal to SIGCHLD so we signal init on exit */
current->exit_signal = SIGCHLD;
@@ -345,9 +391,9 @@ void daemonize(const char *name, ...)
exit_mm(current);
set_special_pids(1, 1);
- down(&tty_sem);
+ mutex_lock(&tty_mutex);
current->signal->tty = NULL;
- up(&tty_sem);
+ mutex_unlock(&tty_mutex);
/* Block and flush all signals */
sigfillset(&blocked);
@@ -536,13 +582,13 @@ static void exit_mm(struct task_struct * tsk)
mmput(mm);
}
-static inline void choose_new_parent(task_t *p, task_t *reaper, task_t *child_reaper)
+static inline void choose_new_parent(task_t *p, task_t *reaper)
{
/*
* Make sure we're not reparenting to ourselves and that
* the parent is not a zombie.
*/
- BUG_ON(p == reaper || reaper->exit_state >= EXIT_ZOMBIE);
+ BUG_ON(p == reaper || reaper->exit_state);
p->real_parent = reaper;
}
@@ -567,9 +613,9 @@ static void reparent_thread(task_t *p, task_t *father, int traced)
* anyway, so let go of it.
*/
p->ptrace = 0;
- list_del_init(&p->sibling);
+ remove_parent(p);
p->parent = p->real_parent;
- list_add_tail(&p->sibling, &p->parent->children);
+ add_parent(p);
/* If we'd notified the old parent about this child's death,
* also notify the new parent.
@@ -643,7 +689,7 @@ static void forget_original_parent(struct task_struct * father,
if (father == p->real_parent) {
/* reparent with a reaper, real father it's us */
- choose_new_parent(p, reaper, child_reaper);
+ choose_new_parent(p, reaper);
reparent_thread(p, father, 0);
} else {
/* reparent ptraced task to its real parent */
@@ -664,7 +710,7 @@ static void forget_original_parent(struct task_struct * father,
}
list_for_each_safe(_p, _n, &father->ptrace_children) {
p = list_entry(_p,struct task_struct,ptrace_list);
- choose_new_parent(p, reaper, child_reaper);
+ choose_new_parent(p, reaper);
reparent_thread(p, father, 1);
}
}
@@ -805,10 +851,8 @@ fastcall NORET_TYPE void do_exit(long code)
panic("Aiee, killing interrupt handler!");
if (unlikely(!tsk->pid))
panic("Attempted to kill the idle task!");
- if (unlikely(tsk->pid == 1))
+ if (unlikely(tsk == child_reaper))
panic("Attempted to kill init!");
- if (tsk->io_context)
- exit_io_context();
if (unlikely(current->ptrace & PT_TRACE_EXIT)) {
current->ptrace_message = code;
@@ -822,6 +866,8 @@ fastcall NORET_TYPE void do_exit(long code)
if (unlikely(tsk->flags & PF_EXITING)) {
printk(KERN_ALERT
"Fixing recursive fault but reboot is needed!\n");
+ if (tsk->io_context)
+ exit_io_context();
set_current_state(TASK_UNINTERRUPTIBLE);
schedule();
}
@@ -852,6 +898,12 @@ fastcall NORET_TYPE void do_exit(long code)
exit_itimers(tsk->signal);
acct_process(code);
}
+ if (unlikely(tsk->robust_list))
+ exit_robust_list(tsk);
+#ifdef CONFIG_COMPAT
+ if (unlikely(tsk->compat_robust_list))
+ compat_exit_robust_list(tsk);
+#endif
exit_mm(tsk);
exit_sem(tsk);
@@ -881,6 +933,9 @@ fastcall NORET_TYPE void do_exit(long code)
*/
mutex_debug_check_no_locks_held(tsk);
+ if (tsk->io_context)
+ exit_io_context();
+
/* PF_DEAD causes final put_task_struct after we schedule. */
preempt_disable();
BUG_ON(tsk->flags & PF_DEAD);
@@ -909,13 +964,6 @@ asmlinkage long sys_exit(int error_code)
do_exit((error_code&0xff)<<8);
}
-task_t fastcall *next_thread(const task_t *p)
-{
- return pid_task(p->pids[PIDTYPE_TGID].pid_list.next, PIDTYPE_TGID);
-}
-
-EXPORT_SYMBOL(next_thread);
-
/*
* Take down every thread in the group. This is called by fatal signals
* as well as by sys_exit_group (below).
@@ -930,7 +978,6 @@ do_group_exit(int exit_code)
else if (!thread_group_empty(current)) {
struct signal_struct *const sig = current->signal;
struct sighand_struct *const sighand = current->sighand;
- read_lock(&tasklist_lock);
spin_lock_irq(&sighand->siglock);
if (sig->flags & SIGNAL_GROUP_EXIT)
/* Another thread got here before we took the lock. */
@@ -940,7 +987,6 @@ do_group_exit(int exit_code)
zap_other_threads(current);
}
spin_unlock_irq(&sighand->siglock);
- read_unlock(&tasklist_lock);
}
do_exit(exit_code);
@@ -1270,7 +1316,7 @@ bail_ref:
/* move to end of parent's list to avoid starvation */
remove_parent(p);
- add_parent(p, p->parent);
+ add_parent(p);
write_unlock_irq(&tasklist_lock);
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-14 18:19:52 +0000