[PATCH 2/2] exec: Rename group_exit_task group_exec_task and correct the Documentation

From: Eric W. Biederman
Date: Fri Jun 19 2020 - 14:37:43 EST



Rename group_exit_task to group_exec_task to make it clear this
field is only used during exec.

Update the comments for the fields group_exec_task and notify_count as
they are only used by exec. Notifications to the execing task aka
group_exec_task happen at 0 and -1.

Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
---
fs/exec.c | 8 ++++----
include/linux/sched/signal.h | 13 +++++--------
kernel/exit.c | 4 ++--
3 files changed, 11 insertions(+), 14 deletions(-)

diff --git a/fs/exec.c b/fs/exec.c
index e6e8a9a70327..0bf8bde6edfd 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1145,7 +1145,7 @@ static int de_thread(struct task_struct *tsk)
return -EAGAIN;
}

- sig->group_exit_task = tsk;
+ sig->group_exec_task = tsk;
sig->notify_count = zap_other_threads(tsk);
if (!thread_group_leader(tsk))
sig->notify_count--;
@@ -1173,7 +1173,7 @@ static int de_thread(struct task_struct *tsk)
write_lock_irq(&tasklist_lock);
/*
* Do this under tasklist_lock to ensure that
- * exit_notify() can't miss ->group_exit_task
+ * exit_notify() can't miss ->group_exec_task
*/
sig->notify_count = -1;
if (likely(leader->exit_state))
@@ -1240,7 +1240,7 @@ static int de_thread(struct task_struct *tsk)
release_task(leader);
}

- sig->group_exit_task = NULL;
+ sig->group_exec_task = NULL;
sig->notify_count = 0;

no_thread_group:
@@ -1253,7 +1253,7 @@ static int de_thread(struct task_struct *tsk)
killed:
/* protects against exit_notify() and __exit_signal() */
read_lock(&tasklist_lock);
- sig->group_exit_task = NULL;
+ sig->group_exec_task = NULL;
sig->notify_count = 0;
read_unlock(&tasklist_lock);
return -EAGAIN;
diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h
index 92c72f5db111..61019d8fe86b 100644
--- a/include/linux/sched/signal.h
+++ b/include/linux/sched/signal.h
@@ -98,13 +98,10 @@ struct signal_struct {

/* thread group exit support */
int group_exit_code;
- /* overloaded:
- * - notify group_exit_task when ->count is equal to notify_count
- * - everyone except group_exit_task is stopped during signal delivery
- * of fatal signals, group_exit_task processes the signal.
- */
+
+ /* exec support, notify group_exec_task when notify_count is 0 or -1 */
int notify_count;
- struct task_struct *group_exit_task;
+ struct task_struct *group_exec_task;

/* thread group stop support, overloads group_exit_code too */
int group_stop_count;
@@ -262,11 +259,11 @@ static inline void signal_set_stop_flags(struct signal_struct *sig,
sig->flags = (sig->flags & ~SIGNAL_STOP_MASK) | flags;
}

-/* If true, all threads except ->group_exit_task have pending SIGKILL */
+/* If true, all threads except ->group_exec_task have pending SIGKILL */
static inline int signal_group_exit(const struct signal_struct *sig)
{
return (sig->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP)) ||
- (sig->group_exit_task != NULL);
+ (sig->group_exec_task != NULL);
}

extern void flush_signals(struct task_struct *);
diff --git a/kernel/exit.c b/kernel/exit.c
index 727150f28103..4206d33b4904 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -115,7 +115,7 @@ static void __exit_signal(struct task_struct *tsk)
* then notify it:
*/
if (sig->notify_count > 0 && !--sig->notify_count)
- wake_up_process(sig->group_exit_task);
+ wake_up_process(sig->group_exec_task);

if (tsk == sig->curr_target)
sig->curr_target = next_thread(tsk);
@@ -672,7 +672,7 @@ static void exit_notify(struct task_struct *tsk, int group_dead)

/* mt-exec, de_thread() is waiting for group leader */
if (unlikely(tsk->signal->notify_count < 0))
- wake_up_process(tsk->signal->group_exit_task);
+ wake_up_process(tsk->signal->group_exec_task);
write_unlock_irq(&tasklist_lock);

list_for_each_entry_safe(p, n, &dead, ptrace_entry) {
--
2.20.1