Merge branch 'signal-for-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

Pull signal/exit/ptrace updates from Eric Biederman:
 "This set of changes deletes some dead code, makes a lot of cleanups
  which hopefully make the code easier to follow, and fixes bugs found
  along the way.

  The end-game which I have not yet reached yet is for fatal signals
  that generate coredumps to be short-circuit deliverable from
  complete_signal, for force_siginfo_to_task not to require changing
  userspace configured signal delivery state, and for the ptrace stops
  to always happen in locations where we can guarantee on all
  architectures that the all of the registers are saved and available on
  the stack.

  Removal of profile_task_ext, profile_munmap, and profile_handoff_task
  are the big successes for dead code removal this round.

  A bunch of small bug fixes are included, as most of the issues
  reported were small enough that they would not affect bisection so I
  simply added the fixes and did not fold the fixes into the changes
  they were fixing.

  There was a bug that broke coredumps piped to systemd-coredump. I
  dropped the change that caused that bug and replaced it entirely with
  something much more restrained. Unfortunately that required some
  rebasing.

  Some successes after this set of changes: There are few enough calls
  to do_exit to audit in a reasonable amount of time. The lifetime of
  struct kthread now matches the lifetime of struct task, and the
  pointer to struct kthread is no longer stored in set_child_tid. The
  flag SIGNAL_GROUP_COREDUMP is removed. The field group_exit_task is
  removed. Issues where task->exit_code was examined with
  signal->group_exit_code should been examined were fixed.

  There are several loosely related changes included because I am
  cleaning up and if I don't include them they will probably get lost.

  The original postings of these changes can be found at:
     https://lkml.kernel.org/r/87a6ha4zsd.fsf@email.froward.int.ebiederm.org
     https://lkml.kernel.org/r/87bl1kunjj.fsf@email.froward.int.ebiederm.org
     https://lkml.kernel.org/r/87r19opkx1.fsf_-_@email.froward.int.ebiederm.org

  I trimmed back the last set of changes to only the obviously correct
  once. Simply because there was less time for review than I had hoped"

* 'signal-for-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (44 commits)
  ptrace/m68k: Stop open coding ptrace_report_syscall
  ptrace: Remove unused regs argument from ptrace_report_syscall
  ptrace: Remove second setting of PT_SEIZED in ptrace_attach
  taskstats: Cleanup the use of task->exit_code
  exit: Use the correct exit_code in /proc/<pid>/stat
  exit: Fix the exit_code for wait_task_zombie
  exit: Coredumps reach do_group_exit
  exit: Remove profile_handoff_task
  exit: Remove profile_task_exit & profile_munmap
  signal: clean up kernel-doc comments
  signal: Remove the helper signal_group_exit
  signal: Rename group_exit_task group_exec_task
  coredump: Stop setting signal->group_exit_task
  signal: Remove SIGNAL_GROUP_COREDUMP
  signal: During coredumps set SIGNAL_GROUP_EXIT in zap_process
  signal: Make coredump handling explicit in complete_signal
  signal: Have prepare_signal detect coredumps using signal->core_state
  signal: Have the oom killer detect coredumps using signal->core_state
  exit: Move force_uaccess back into do_exit
  exit: Guarantee make_task_dead leaks the tsk when calling do_task_exit
  ...

9 files changed, 20 insertions, 75 deletions

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 77755ac3e189..055eb203c00e 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -187,7 +187,6 @@ static inline void might_fault(void) { }
 #endif
 
 void do_exit(long error_code) __noreturn;
-void complete_and_exit(struct completion *, long) __noreturn;
 
 extern int num_to_str(char *buf, int size,
 		      unsigned long long num, unsigned int width);
diff --git a/include/linux/kthread.h b/include/linux/kthread.h
index db47aae7c481..b6c8aafa8db5 100644
--- a/include/linux/kthread.h
+++ b/include/linux/kthread.h
@@ -33,7 +33,7 @@ struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data),
 					  unsigned int cpu,
 					  const char *namefmt);
 
-void set_kthread_struct(struct task_struct *p);
+bool set_kthread_struct(struct task_struct *p);
 
 void kthread_set_per_cpu(struct task_struct *k, int cpu);
 bool kthread_is_per_cpu(struct task_struct *k);
@@ -95,6 +95,8 @@ void *kthread_probe_data(struct task_struct *k);
 int kthread_park(struct task_struct *k);
 void kthread_unpark(struct task_struct *k);
 void kthread_parkme(void);
+void kthread_exit(long result) __noreturn;
+void kthread_complete_and_exit(struct completion *, long) __noreturn;
 
 int kthreadd(void *unused);
 extern struct task_struct *kthreadd_task;
diff --git a/include/linux/module.h b/include/linux/module.h
index c9f1200b2312..f03be97e9ec1 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -595,9 +595,9 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
 /* Look for this name: can be of form module:name. */
 unsigned long module_kallsyms_lookup_name(const char *name);
 
-extern void __noreturn __module_put_and_exit(struct module *mod,
+extern void __noreturn __module_put_and_kthread_exit(struct module *mod,
 			long code);
-#define module_put_and_exit(code) __module_put_and_exit(THIS_MODULE, code)
+#define module_put_and_kthread_exit(code) __module_put_and_kthread_exit(THIS_MODULE, code)
 
 #ifdef CONFIG_MODULE_UNLOAD
 int module_refcount(struct module *mod);
@@ -790,7 +790,7 @@ static inline int unregister_module_notifier(struct notifier_block *nb)
 	return 0;
 }
 
-#define module_put_and_exit(code) do_exit(code)
+#define module_put_and_kthread_exit(code) kthread_exit(code)
 
 static inline void print_modules(void)
 {
diff --git a/include/linux/profile.h b/include/linux/profile.h
index fd18ca96f557..11db1ec516e2 100644
--- a/include/linux/profile.h
+++ b/include/linux/profile.h
@@ -31,11 +31,6 @@ static inline int create_proc_profile(void)
 }
 #endif
 
-enum profile_type {
-	PROFILE_TASK_EXIT,
-	PROFILE_MUNMAP
-};
-
 #ifdef CONFIG_PROFILING
 
 extern int prof_on __read_mostly;
@@ -66,23 +61,6 @@ static inline void profile_hit(int type, void *ip)
 struct task_struct;
 struct mm_struct;
 
-/* task is in do_exit() */
-void profile_task_exit(struct task_struct * task);
-
-/* task is dead, free task struct ? Returns 1 if
- * the task was taken, 0 if the task should be freed.
- */
-int profile_handoff_task(struct task_struct * task);
-
-/* sys_munmap */
-void profile_munmap(unsigned long addr);
-
-int task_handoff_register(struct notifier_block * n);
-int task_handoff_unregister(struct notifier_block * n);
-
-int profile_event_register(enum profile_type, struct notifier_block * n);
-int profile_event_unregister(enum profile_type, struct notifier_block * n);
-
 #else
 
 #define prof_on 0
@@ -107,29 +85,6 @@ static inline void profile_hit(int type, void *ip)
 	return;
 }
 
-static inline int task_handoff_register(struct notifier_block * n)
-{
-	return -ENOSYS;
-}
-
-static inline int task_handoff_unregister(struct notifier_block * n)
-{
-	return -ENOSYS;
-}
-
-static inline int profile_event_register(enum profile_type t, struct notifier_block * n)
-{
-	return -ENOSYS;
-}
-
-static inline int profile_event_unregister(enum profile_type t, struct notifier_block * n)
-{
-	return -ENOSYS;
-}
-
-#define profile_task_exit(a) do { } while (0)
-#define profile_handoff_task(a) (0)
-#define profile_munmap(a) do { } while (0)
 
 #endif /* CONFIG_PROFILING */
 
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 7a1f16df66e3..a6a2db5f85ac 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -991,8 +991,8 @@ struct task_struct {
 	/* CLONE_CHILD_CLEARTID: */
 	int __user			*clear_child_tid;
 
-	/* PF_IO_WORKER */
-	void				*pf_io_worker;
+	/* PF_KTHREAD | PF_IO_WORKER */
+	void				*worker_private;
 
 	u64				utime;
 	u64				stime;
diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h
index 33a50642cf41..b6ecb9fc4cd2 100644
--- a/include/linux/sched/signal.h
+++ b/include/linux/sched/signal.h
@@ -109,13 +109,9 @@ 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.
-	 */
+	/* notify group_exec_task when notify_count is less or equal to 0 */
 	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;
@@ -256,7 +252,6 @@ struct signal_struct {
 #define SIGNAL_STOP_STOPPED	0x00000001 /* job control stop in effect */
 #define SIGNAL_STOP_CONTINUED	0x00000002 /* SIGCONT since WCONTINUED reap */
 #define SIGNAL_GROUP_EXIT	0x00000004 /* group exit in progress */
-#define SIGNAL_GROUP_COREDUMP	0x00000008 /* coredump in progress */
 /*
  * Pending notifications to parent.
  */
@@ -272,31 +267,25 @@ struct signal_struct {
 static inline void signal_set_stop_flags(struct signal_struct *sig,
 					 unsigned int flags)
 {
-	WARN_ON(sig->flags & (SIGNAL_GROUP_EXIT|SIGNAL_GROUP_COREDUMP));
+	WARN_ON(sig->flags & SIGNAL_GROUP_EXIT);
 	sig->flags = (sig->flags & ~SIGNAL_STOP_MASK) | flags;
 }
 
-/* If true, all threads except ->group_exit_task have pending SIGKILL */
-static inline int signal_group_exit(const struct signal_struct *sig)
-{
-	return	(sig->flags & SIGNAL_GROUP_EXIT) ||
-		(sig->group_exit_task != NULL);
-}
-
 extern void flush_signals(struct task_struct *);
 extern void ignore_signals(struct task_struct *);
 extern void flush_signal_handlers(struct task_struct *, int force_default);
-extern int dequeue_signal(struct task_struct *task,
-			  sigset_t *mask, kernel_siginfo_t *info);
+extern int dequeue_signal(struct task_struct *task, sigset_t *mask,
+			  kernel_siginfo_t *info, enum pid_type *type);
 
 static inline int kernel_dequeue_signal(void)
 {
 	struct task_struct *task = current;
 	kernel_siginfo_t __info;
+	enum pid_type __type;
 	int ret;
 
 	spin_lock_irq(&task->sighand->siglock);
-	ret = dequeue_signal(task, &task->blocked, &__info);
+	ret = dequeue_signal(task, &task->blocked, &__info, &__type);
 	spin_unlock_irq(&task->sighand->siglock);
 
 	return ret;
diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h
index 058d7f371e25..b9198a1b3a84 100644
--- a/include/linux/sched/task.h
+++ b/include/linux/sched/task.h
@@ -59,6 +59,7 @@ extern void sched_post_fork(struct task_struct *p,
 extern void sched_dead(struct task_struct *p);
 
 void __noreturn do_task_dead(void);
+void __noreturn make_task_dead(int signr);
 
 extern void proc_caches_init(void);
 
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index cf175d47c6b7..f35c22b3355f 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -65,7 +65,7 @@ struct svc_serv_ops {
 	void		(*svo_enqueue_xprt)(struct svc_xprt *);
 
 	/* optional module to count when adding threads.
-	 * Thread function must call module_put_and_exit() to exit.
+	 * Thread function must call module_put_and_kthread_exit() to exit.
 	 */
 	struct module	*svo_module;
 };
diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h
index 2564b7434b4d..88c007ab5ebc 100644
--- a/include/linux/tracehook.h
+++ b/include/linux/tracehook.h
@@ -54,8 +54,7 @@ struct linux_binprm;
 /*
  * ptrace report for syscall entry and exit looks identical.
  */
-static inline int ptrace_report_syscall(struct pt_regs *regs,
-					unsigned long message)
+static inline int ptrace_report_syscall(unsigned long message)
 {
 	int ptrace = current->ptrace;
 
@@ -102,7 +101,7 @@ static inline int ptrace_report_syscall(struct pt_regs *regs,
 static inline __must_check int tracehook_report_syscall_entry(
 	struct pt_regs *regs)
 {
-	return ptrace_report_syscall(regs, PTRACE_EVENTMSG_SYSCALL_ENTRY);
+	return ptrace_report_syscall(PTRACE_EVENTMSG_SYSCALL_ENTRY);
 }
 
 /**
@@ -127,7 +126,7 @@ static inline void tracehook_report_syscall_exit(struct pt_regs *regs, int step)
 	if (step)
 		user_single_step_report(regs);
 	else
-		ptrace_report_syscall(regs, PTRACE_EVENTMSG_SYSCALL_EXIT);
+		ptrace_report_syscall(PTRACE_EVENTMSG_SYSCALL_EXIT);
 }
 
 /**