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Commit e8cd8169 authored by Al Viro's avatar Al Viro
Browse files

vt: synchronize_rcu() under spinlock is not nice... 



vcs_poll_data_free() calls unregister_vt_notifier(), which calls
atomic_notifier_chain_unregister(), which calls synchronize_rcu().
Do it *after* we'd dropped ->f_lock.

Cc: stable@vger.kernel.org (all kernels since 2.6.37)
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 7ea600b5

drivers/tty/vt/vc_screen.c

+4 −2
Original line number Diff line number Diff line
@@ -93,7 +93,7 @@ vcs_poll_data_free(struct vcs_poll_data *poll) 
static struct vcs_poll_data *

vcs_poll_data_get(struct file *file)

{

	struct vcs_poll_data *poll = file->private_data;

	struct vcs_poll_data *poll = file->private_data, *kill = NULL;



	if (poll)

		return poll;
@@ -122,10 +122,12 @@ vcs_poll_data_get(struct file *file) 
		file->private_data = poll;

	} else {

		/* someone else raced ahead of us */

		vcs_poll_data_free(poll);

		kill = poll;

		poll = file->private_data;

	}

	spin_unlock(&file->f_lock);

	if (kill)

		vcs_poll_data_free(kill);



	return poll;

}