Commit fc321d2e authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
Browse files

handle_stop_signal: unify partial/full stop handling 



Now that handle_stop_signal() doesn't drop ->siglock, we can't see both
->group_stop_count && SIGNAL_STOP_STOPPED.  Merge two "if" branches.

As Roland pointed out, we never actually needed 2 do_notify_parent_cldstop()
calls.

Signed-off-by: default avatarOleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 6ca25b55

kernel/signal.c

+19 −26
Original line number Diff line number Diff line
@@ -585,33 +585,16 @@ static void handle_stop_signal(int sig, struct task_struct *p) 
			t = next_thread(t);

		} while (t != p);

	} else if (sig == SIGCONT) {

		unsigned int why;

		/*

		 * Remove all stop signals from all queues,

		 * and wake all threads.

		 */

		if (unlikely(p->signal->group_stop_count > 0)) {

			/*

			 * There was a group stop in progress.  We'll

			 * pretend it finished before we got here.  We are

			 * obliged to report it to the parent: if the

			 * SIGSTOP happened "after" this SIGCONT, then it

			 * would have cleared this pending SIGCONT.  If it

			 * happened "before" this SIGCONT, then the parent

			 * got the SIGCHLD about the stop finishing before

			 * the continue happened.  We do the notification

			 * now, and it's as if the stop had finished and

			 * the SIGCHLD was pending on entry to this kill.

			 */

			p->signal->group_stop_count = 0;

			p->signal->flags = SIGNAL_STOP_CONTINUED |

						SIGNAL_CLD_STOPPED;

		}

		rm_from_queue(SIG_KERNEL_STOP_MASK, &p->signal->shared_pending);

		t = p;

		do {

			unsigned int state;

			rm_from_queue(SIG_KERNEL_STOP_MASK, &t->pending);

			

			/*

			 * If there is a handler for SIGCONT, we must make

			 * sure that no thread returns to user mode before
@@ -636,13 +619,23 @@ static void handle_stop_signal(int sig, struct task_struct *p) 
			t = next_thread(t);

		} while (t != p);



		if (p->signal->flags & SIGNAL_STOP_STOPPED) {

		/*

			 * We were in fact stopped, and are now continued.

			 * Notify the parent with CLD_CONTINUED.

			 */

			p->signal->flags = SIGNAL_STOP_CONTINUED |

						SIGNAL_CLD_CONTINUED;

		 * Notify the parent with CLD_CONTINUED if we were stopped.

		 *

		 * If we were in the middle of a group stop, we pretend it

		 * was already finished, and then continued. Since SIGCHLD

		 * doesn't queue we report only CLD_STOPPED, as if the next

		 * CLD_CONTINUED was dropped.

		 */

		why = 0;

		if (p->signal->flags & SIGNAL_STOP_STOPPED)

			why |= SIGNAL_CLD_CONTINUED;

		else if (p->signal->group_stop_count)

			why |= SIGNAL_CLD_STOPPED;



		if (why) {

			p->signal->flags = why | SIGNAL_STOP_CONTINUED;

			p->signal->group_stop_count = 0;

			p->signal->group_exit_code = 0;

		} else {

			/*

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