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authorLinus Torvalds <torvalds@linux-foundation.org>2018-08-21 13:47:29 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-08-21 13:47:29 -0700
commit0214f46b3a0383d6e33c297e7706216b6a550e4b (patch)
tree98f94fa818963d4c2b5ad2a16cd97ec19d036dce /include/linux/sched
parent40fafdcbcd7a74e80ab0229b35bf6e497831e28f (diff)
parent84fe4cc09abc1a5ef3a282db3ed10f4d3f1e6a0b (diff)
Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull core signal handling updates from Eric Biederman: "It was observed that a periodic timer in combination with a sufficiently expensive fork could prevent fork from every completing. This contains the changes to remove the need for that restart. This set of changes is split into several parts: - The first part makes PIDTYPE_TGID a proper pid type instead something only for very special cases. The part starts using PIDTYPE_TGID enough so that in __send_signal where signals are actually delivered we know if the signal is being sent to a a group of processes or just a single process. - With that prep work out of the way the logic in fork is modified so that fork logically makes signals received while it is running appear to be received after the fork completes" * 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (22 commits) signal: Don't send signals to tasks that don't exist signal: Don't restart fork when signals come in. fork: Have new threads join on-going signal group stops fork: Skip setting TIF_SIGPENDING in ptrace_init_task signal: Add calculate_sigpending() fork: Unconditionally exit if a fatal signal is pending fork: Move and describe why the code examines PIDNS_ADDING signal: Push pid type down into complete_signal. signal: Push pid type down into __send_signal signal: Push pid type down into send_signal signal: Pass pid type into do_send_sig_info signal: Pass pid type into send_sigio_to_task & send_sigurg_to_task signal: Pass pid type into group_send_sig_info signal: Pass pid and pid type into send_sigqueue posix-timers: Noralize good_sigevent signal: Use PIDTYPE_TGID to clearly store where file signals will be sent pid: Implement PIDTYPE_TGID pids: Move the pgrp and session pid pointers from task_struct to signal_struct kvm: Don't open code task_pid in kvm_vcpu_ioctl pids: Compute task_tgid using signal->leader_pid ...
Diffstat (limited to 'include/linux/sched')
-rw-r--r--include/linux/sched/signal.h49
1 files changed, 46 insertions, 3 deletions
diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h
index 113d1ad1ced7..4e9b77fb702d 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;
@@ -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