[PATCH 14/17] signal: Remove zap_other_threads

Eric W. Biederman
2022-01-03T21:34:28Z

The two callers of zap_other_threads want different things. The
function do_group_exit wants to set the exit code and it does not care
about the number of threads exiting. In de_thread the current thread
is not exiting so there is not really an exit code.

Since schedule_task_exit_locked factors out the tricky bits stop
sharing the loop in zap_other_threads between de_thread and
do_group_exit.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
fs/exec.c | 12 +++++++++---
include/linux/sched/signal.h | 1 -
kernel/exit.c | 9 ++++++++-
kernel/signal.c | 17 -----------------
4 files changed, 17 insertions(+), 22 deletions(-)

diff --git a/fs/exec.c b/fs/exec.c
index 82db656ca709..b9f646fddc51 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1037,6 +1037,7 @@ static int de_thread(struct task_struct *tsk)
struct signal_struct *sig = tsk->signal;
struct sighand_struct *oldsighand = tsk->sighand;
spinlock_t *lock = &oldsighand->siglock;
+ struct task_struct *t;

if (thread_group_empty(tsk))
goto no_thread_group;
@@ -1055,9 +1056,14 @@ static int de_thread(struct task_struct *tsk)
}

sig->group_exec_task = tsk;
- sig->notify_count = zap_other_threads(tsk);
- if (!thread_group_leader(tsk))
- sig->notify_count--;
+ sig->group_stop_count = 0;
+ sig->notify_count = 0;
+ __for_each_thread(sig, t) {
+ if (t == tsk)
+ continue;
+ sig->notify_count++;
+ schedule_task_exit_locked(t);
+ }

while (sig->notify_count) {
__set_current_state(TASK_KILLABLE);
diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h
index 7c62b7c29cc0..eed54f9ea2fc 100644
--- a/include/linux/sched/signal.h
+++ b/include/linux/sched/signal.h
@@ -343,7 +343,6 @@ extern void force_sig(int);
extern void force_fatal_sig(int);
extern void force_exit_sig(int);
extern int send_sig(int, struct task_struct *, int);
-extern int zap_other_threads(struct task_struct *p);
extern struct sigqueue *sigqueue_alloc(void);
extern void sigqueue_free(struct sigqueue *);
extern int send_sigqueue(struct sigqueue *, struct pid *, enum pid_type);
diff --git a/kernel/exit.c b/kernel/exit.c
index aedefe5eb0eb..27bc0ccfea78 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -918,9 +918,16 @@ do_group_exit(int exit_code)
else if (sig->group_exec_task)
exit_code = 0;
else {
+ struct task_struct *t;
+
sig->group_exit_code = exit_code;
sig->flags = SIGNAL_GROUP_EXIT;
- zap_other_threads(current);
+ sig->group_stop_count = 0;
+ __for_each_thread(sig, t) {
+ if (t == current)
+ continue;
+ schedule_task_exit_locked(t);
+ }
}
spin_unlock_irq(&sighand->siglock);
}
diff --git a/kernel/signal.c b/kernel/signal.c
index cbfb9020368e..b0201e05be40 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1371,23 +1371,6 @@ void schedule_task_exit_locked(struct task_struct *task)
}
}

-/*
- * Nuke all other threads in the group.
- */
-int zap_other_threads(struct task_struct *p)
-{
- struct task_struct *t = p;
- int count = 0;
-
- p->signal->group_stop_count = 0;
-
- while_each_thread(p, t) {
- count++;
- schedule_task_exit_locked(t);
- }
- return count;
-}
-
struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
unsigned long *flags)
{
--
2.29.2