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authorAl Viro <viro@zeniv.linux.org.uk>2013-03-26 20:30:17 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2013-03-26 20:30:17 -0400
commite8cd81693bbbb15db57d3c9aa7dd90eda4842874 (patch)
treef8ba631b03652f9e570fa1e8bd0395af63cf2bb3
parent7ea600b5314529f9d1b9d6d3c41cb26fce6a7a4a (diff)
downloadlinux-e8cd81693bbbb15db57d3c9aa7dd90eda4842874.tar.bz2
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: Al Viro <viro@zeniv.linux.org.uk>
-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 e4ca345873c3..d7799deacb21 100644
--- a/drivers/tty/vt/vc_screen.c
+++ b/drivers/tty/vt/vc_screen.c
@@ -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;
}