Commit 5876700c authored Mar 28, 2006 by Oleg Nesterov Committed by Linus Torvalds Mar 28, 2006

[PATCH] do __unhash_process() under ->siglock



This patch moves __unhash_process() call from realease_task() to
__exit_signal(), so __detach_pid() is called with ->siglock held.

This means we don't need tasklist_lock to iterate over thread group anymore:

	copy_process() was already changed to do attach_pid()
	under ->siglock.

	Eric's "pidhash-kill-switch_exec_pids.patch" from -mm
	changed de_thread() so it doesn't touch PIDTYPE_TGID.

NOTE: de_thread() still needs some attention.  It still changes task->pid
lockless.  Taking ->sighand.siglock here allows to do more tasklist_lock
removals.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent 35f5cad8

kernel/exit.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -112,6 +112,8 @@ static void __exit_signal(struct task_struct *tsk)
		sig = NULL; /* Marker for below. */
		}

		__unhash_process(tsk);

		tsk->signal = NULL;
		cleanup_sighand(tsk);
		spin_unlock(&sighand->siglock);
		@@ -140,8 +142,6 @@ repeat:
		BUG_ON(!list_empty(&p->ptrace_list) \|\| !list_empty(&p->ptrace_children));
		__exit_signal(p);

		__unhash_process(p);

		/*
		* If we are the last non-leader member of the thread
		* group, and the leader is zombie, then notify the

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