[PATCH 4/9] signal: Factor start_group_exit out of complete_signal

Eric W. Biederman
2021-06-24T19:01:31Z

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
include/linux/sched/signal.h | 2 ++
kernel/signal.c | 52 +++++++++++++++++++++++++-----------
2 files changed, 39 insertions(+), 15 deletions(-)

diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h
index 774be5d3ac3e..c007e55cb119 100644
--- a/include/linux/sched/signal.h
+++ b/include/linux/sched/signal.h
@@ -428,6 +428,8 @@ static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume)
signal_wake_up_state(t, resume ? __TASK_TRACED : 0);
}

+void start_group_exit(int exit_code);
+
void task_join_group_stop(struct task_struct *task);

#ifdef TIF_RESTORE_SIGMASK
diff --git a/kernel/signal.c b/kernel/signal.c
index da37cc4515f2..c79c010ca5f3 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1027,6 +1027,42 @@ static inline bool wants_signal(int sig, struct task_struct *p)
return task_curr(p) || !task_sigpending(p);
}

+static void start_group_exit_locked(struct signal_struct *signal, int exit_code)
+{
+ /*
+ * Start a group exit and wake everybody up.
+ * This way we don't have other threads
+ * running and doing things after a slower
+ * thread has the fatal signal pending.
+ */
+ struct task_struct *t;
+
+ signal->flags = SIGNAL_GROUP_EXIT;
+ signal->group_exit_code = exit_code;
+ signal->group_stop_count = 0;
+ __for_each_thread(signal, t) {
+ task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
+
+ /* Don't bother with already dead threads */
+ if (t->exit_state)
+ continue;
+ sigaddset(&t->pending.signal, SIGKILL);
+ signal_wake_up(t, 1);
+ }
+}
+
+void start_group_exit(int exit_code)
+{
+ if (!fatal_signal_pending(current)) {
+ struct sighand_struct *const sighand = current->sighand;
+
+ spin_lock_irq(&sighand->siglock);
+ if (!fatal_signal_pending(current))
+ start_group_exit_locked(current->signal, exit_code);
+ spin_unlock_irq(&sighand->siglock);
+ }
+}
+
static void complete_signal(int sig, struct task_struct *p, enum pid_type type)
{
struct signal_struct *signal = p->signal;
@@ -1076,21 +1112,7 @@ static void complete_signal(int sig, struct task_struct *p, enum pid_type type)
* This signal will be fatal to the whole group.
*/
if (!sig_kernel_coredump(sig)) {
- /*
- * Start a group exit and wake everybody up.
- * This way we don't have other threads
- * running and doing things after a slower
- * thread has the fatal signal pending.
- */
- signal->flags = SIGNAL_GROUP_EXIT;
- signal->group_exit_code = sig;
- signal->group_stop_count = 0;
- t = p;
- do {
- task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
- sigaddset(&t->pending.signal, SIGKILL);
- signal_wake_up(t, 1);
- } while_each_thread(p, t);
+ start_group_exit_locked(signal, sig);
return;
}
}
--
2.20.1