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authorAl Viro <viro@zeniv.linux.org.uk>2013-03-26 20:30:17 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-04-05 10:16:36 -0700
commit8cc034e4c1b7901787bbf72908bc584c055b5e09 (patch)
treea6434b15e0fb353c800568358fcfd22ae50bad59
parent19c85a53434ec90c1c6d6b0717e1eb37c5f2f84d (diff)
downloadlinux-linaro-stable-8cc034e4c1b7901787bbf72908bc584c055b5e09.tar.gz
vt: synchronize_rcu() under spinlock is not nice...
commit e8cd81693bbbb15db57d3c9aa7dd90eda4842874 upstream. 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. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/tty/vt/vc_screen.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/tty/vt/vc_screen.c b/drivers/tty/vt/vc_screen.c
index 66825c9f516a..ab2320112bfe 100644
--- a/drivers/tty/vt/vc_screen.c
+++ b/drivers/tty/vt/vc_screen.c
@@ -92,7 +92,7 @@ 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;
@@ -121,10 +121,12 @@ 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;
}