1 files changed, 47 insertions, 4 deletions

diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h
index 113d1ad1ced7..1be35729c2c5 100644
--- a/include/linux/sched/signal.h
+++ b/include/linux/sched/signal.h
@@ -69,6 +69,11 @@ struct thread_group_cputimer {
         bool checking_timer;
 };
 
+struct multiprocess_signals {
+        sigset_t signal;
+        struct hlist_node node;
+};
+
 /*
  * NOTE! "signal_struct" does not have its own
  * locking, because a shared signal_struct always
@@ -90,6 +95,9 @@ struct signal_struct {
         /* shared signal handling: */
         struct sigpending       shared_pending;
 
+        /* For collecting multiprocess signals during fork */
+        struct hlist_head       multiprocess;
+
         /* thread group exit support */
         int                     group_exit_code;
         /* overloaded:
@@ -146,7 +154,8 @@ struct signal_struct {
 
 #endif
 
-        struct pid *leader_pid;
+        /* PID/PID hash table linkage. */
+        struct pid *pids[PIDTYPE_MAX];
 
 #ifdef CONFIG_NO_HZ_FULL
         atomic_t tick_dep_mask;
@@ -314,7 +323,7 @@ int force_sig_pkuerr(void __user *addr, u32 pkey);
 int force_sig_ptrace_errno_trap(int errno, void __user *addr);
 
 extern int send_sig_info(int, struct siginfo *, struct task_struct *);
-extern int force_sigsegv(int, struct task_struct *);
+extern void force_sigsegv(int sig, struct task_struct *p);
 extern int force_sig_info(int, struct siginfo *, struct task_struct *);
 extern int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp);
 extern int kill_pid_info(int sig, struct siginfo *info, struct pid *pid);
@@ -329,7 +338,7 @@ 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 task_struct *, int group);
+extern int send_sigqueue(struct sigqueue *, struct pid *, enum pid_type);
 extern int do_sigaction(int, struct k_sigaction *, struct k_sigaction *);
 
 static inline int restart_syscall(void)
@@ -371,6 +380,7 @@ static inline int signal_pending_state(long state, struct task_struct *p)
  */
 extern void recalc_sigpending_and_wake(struct task_struct *t);
 extern void recalc_sigpending(void);
+extern void calculate_sigpending(void);
 
 extern void signal_wake_up_state(struct task_struct *t, unsigned int state);
 
@@ -383,6 +393,8 @@ static inline void ptrace_signal_wake_up(struct task_struct *t, bool resume)
         signal_wake_up_state(t, resume ? __TASK_TRACED : 0);
 }
 
+void task_join_group_stop(struct task_struct *task);
+
 #ifdef TIF_RESTORE_SIGMASK
 /*
  * Legacy restore_sigmask accessors.  These are inefficient on
@@ -556,6 +568,37 @@ extern bool current_is_single_threaded(void);
 typedef int (*proc_visitor)(struct task_struct *p, void *data);
 void walk_process_tree(struct task_struct *top, proc_visitor, void *);
 
+static inline
+struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
+{
+        struct pid *pid;
+        if (type == PIDTYPE_PID)
+                pid = task_pid(task);
+        else
+                pid = task->signal->pids[type];
+        return pid;
+}
+
+static inline struct pid *task_tgid(struct task_struct *task)
+{
+        return task->signal->pids[PIDTYPE_TGID];
+}
+
+/*
+ * Without tasklist or RCU lock it is not safe to dereference
+ * the result of task_pgrp/task_session even if task == current,
+ * we can race with another thread doing sys_setsid/sys_setpgid.
+ */
+static inline struct pid *task_pgrp(struct task_struct *task)
+{
+        return task->signal->pids[PIDTYPE_PGID];
+}
+
+static inline struct pid *task_session(struct task_struct *task)
+{
+        return task->signal->pids[PIDTYPE_SID];
+}
+
 static inline int get_nr_threads(struct task_struct *tsk)
 {
         return tsk->signal->nr_threads;
@@ -574,7 +617,7 @@ static inline bool thread_group_leader(struct task_struct *p)
  */
 static inline bool has_group_leader_pid(struct task_struct *p)
 {
-        return task_pid(p) == p->signal->leader_pid;
+        return task_pid(p) == task_tgid(p);
 }
 
 static inline