Commit e572410e authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'signal-for-v5.20' of... 

Merge tag 'signal-for-v5.20' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

Pull ptrace update from Eric Biederman:
 "ptrace: Stop supporting SIGKILL for PTRACE_EVENT_EXIT

  Recently I had a conversation where it was pointed out to me that
  SIGKILL sent to a tracee stropped in PTRACE_EVENT_EXIT is quite
  difficult for a tracer to handle.

  Keeping SIGKILL working after the process has been killed is pain from
  an implementation point of view.

  So since the debuggers don't want this behavior let's see if we can
  remove this wart for the userspace API

  If a regression is detected it should only need to be the last change
  that is the reverted. The other two are just general cleanups that
  make the last patch simpler"

* tag 'signal-for-v5.20' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  signal: Drop signals received after a fatal signal has been processed
  signal: Guarantee that SIGNAL_GROUP_EXIT is set on process exit
  signal: Ensure SIGNAL_GROUP_EXIT gets set in do_group_exit
parents 86fb9c53 9a95f78e

fs/coredump.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -354,7 +354,7 @@ static int zap_process(struct task_struct *start, int exit_code) 
	struct task_struct *t;

	struct task_struct *t;

	int nr = 0;

	int nr = 0;





	/* ignore all signals except SIGKILL, see prepare_signal() */

	/* Allow SIGKILL, see prepare_signal() */

	start->signal->flags = SIGNAL_GROUP_EXIT;

	start->signal->flags = SIGNAL_GROUP_EXIT;

	start->signal->group_exit_code = exit_code;

	start->signal->group_exit_code = exit_code;

	start->signal->group_stop_count = 0;

	start->signal->group_stop_count = 0;

include/linux/sched/signal.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -94,6 +94,7 @@ struct signal_struct { 
	refcount_t		sigcnt;

	refcount_t		sigcnt;

	atomic_t		live;

	atomic_t		live;

	int			nr_threads;

	int			nr_threads;

	int			quick_threads;

	struct list_head	thread_head;

	struct list_head	thread_head;





	wait_queue_head_t	wait_chldexit;	/* for wait4() */

	wait_queue_head_t	wait_chldexit;	/* for wait4() */

kernel/exit.c

+19 −1
Original line number Original line Diff line number Diff line
@@ -733,11 +733,29 @@ static void check_stack_usage(void) 
static inline void check_stack_usage(void) {}

static inline void check_stack_usage(void) {}

#endif

#endif





static void synchronize_group_exit(struct task_struct *tsk, long code)

{

	struct sighand_struct *sighand = tsk->sighand;

	struct signal_struct *signal = tsk->signal;



	spin_lock_irq(&sighand->siglock);

	signal->quick_threads--;

	if ((signal->quick_threads == 0) &&

	    !(signal->flags & SIGNAL_GROUP_EXIT)) {

		signal->flags = SIGNAL_GROUP_EXIT;

		signal->group_exit_code = code;

		signal->group_stop_count = 0;

	}

	spin_unlock_irq(&sighand->siglock);

}



void __noreturn do_exit(long code)

void __noreturn do_exit(long code)

{

{

	struct task_struct *tsk = current;

	struct task_struct *tsk = current;

	int group_dead;

	int group_dead;





	synchronize_group_exit(tsk, code);



	WARN_ON(tsk->plug);

	WARN_ON(tsk->plug);





	kcov_task_exit(tsk);

	kcov_task_exit(tsk);
@@ -905,7 +923,7 @@ do_group_exit(int exit_code) 
		exit_code = sig->group_exit_code;

		exit_code = sig->group_exit_code;

	else if (sig->group_exec_task)

	else if (sig->group_exec_task)

		exit_code = 0;

		exit_code = 0;

	else if (!thread_group_empty(current)) {

	else {

		struct sighand_struct *const sighand = current->sighand;

		struct sighand_struct *const sighand = current->sighand;





		spin_lock_irq(&sighand->siglock);

		spin_lock_irq(&sighand->siglock);

kernel/fork.c

+2 −0
Original line number Original line Diff line number Diff line
@@ -1693,6 +1693,7 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk) 
		return -ENOMEM;

		return -ENOMEM;





	sig->nr_threads = 1;

	sig->nr_threads = 1;

	sig->quick_threads = 1;

	atomic_set(&sig->live, 1);

	atomic_set(&sig->live, 1);

	refcount_set(&sig->sigcnt, 1);

	refcount_set(&sig->sigcnt, 1);
@@ -2460,6 +2461,7 @@ static __latent_entropy struct task_struct *copy_process( 
			__this_cpu_inc(process_counts);

			__this_cpu_inc(process_counts);

		} else {

		} else {

			current->signal->nr_threads++;

			current->signal->nr_threads++;

			current->signal->quick_threads++;

			atomic_inc(&current->signal->live);

			atomic_inc(&current->signal->live);

			refcount_inc(&current->signal->sigcnt);

			refcount_inc(&current->signal->sigcnt);

			task_join_group_stop(p);

			task_join_group_stop(p);

kernel/signal.c

+2 −1
Original line number Original line Diff line number Diff line
@@ -913,8 +913,9 @@ static bool prepare_signal(int sig, struct task_struct *p, bool force) 
		if (signal->core_state)

		if (signal->core_state)

			return sig == SIGKILL;

			return sig == SIGKILL;

		/*

		/*

		 * The process is in the middle of dying, nothing to do.

		 * The process is in the middle of dying, drop the signal.

		 */

		 */

		return false;

	} else if (sig_kernel_stop(sig)) {

	} else if (sig_kernel_stop(sig)) {

		/*

		/*

		 * This is a stop signal.  Remove SIGCONT from all queues.

		 * This is a stop signal.  Remove SIGCONT from all queues.