vt: selection, push console lock down

commit 4b70dd57a15d2f4685ac6e38056bad93e81e982f upstream.

We need to nest the console lock in sel_lock, so we have to push it down
a bit. Fortunately, the callers of set_selection_* just lock the console
lock around the function call. So moving it down is easy.

In the next patch, we switch the order.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Fixes: 07e6124a1a46 ("vt: selection, close sel_buffer race")
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200228115406.5735-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/speakup/selection.c b/drivers/staging/speakup/selection.c
index a8b4d0c..032f326 100644 (file)
--- a/drivers/staging/speakup/selection.c
+++ b/drivers/staging/speakup/selection.c
@@ -51,9 +51,7 @@ static void __speakup_set_selection(struct work_struct *work)
                goto unref;
        }
 
-       console_lock();
        set_selection_kernel(&sel, tty);
-       console_unlock();
 
 unref:
        tty_kref_put(tty);

diff --git a/drivers/tty/vt/selection.c b/drivers/tty/vt/selection.c
index 0c50d74..9126a01 100644 (file)
--- a/drivers/tty/vt/selection.c
+++ b/drivers/tty/vt/selection.c
@@ -181,7 +181,7 @@ int set_selection_user(const struct tiocl_selection __user *sel,
        return set_selection_kernel(&v, tty);
 }
 
-int set_selection_kernel(struct tiocl_selection *v, struct tty_struct *tty)
+static int __set_selection_kernel(struct tiocl_selection *v, struct tty_struct *tty)
 {
        struct vc_data *vc = vc_cons[fg_console].d;
        int new_sel_start, new_sel_end, spc;
@@ -343,6 +343,17 @@ unlock:
        mutex_unlock(&sel_lock);
        return ret;
 }
+
+int set_selection_kernel(struct tiocl_selection *v, struct tty_struct *tty)
+{
+       int ret;
+
+       console_lock();
+       ret = __set_selection_kernel(v, tty);
+       console_unlock();
+
+       return ret;
+}
 EXPORT_SYMBOL_GPL(set_selection_kernel);
 
 /* Insert the contents of the selection buffer into the

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 3b4ccc2..e9e27ba 100644 (file)
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -3046,10 +3046,8 @@ int tioclinux(struct tty_struct *tty, unsigned long arg)
        switch (type)
        {
                case TIOCL_SETSEL:
-                       console_lock();
                        ret = set_selection_user((struct tiocl_selection
                                                 __user *)(p+1), tty);
-                       console_unlock();
                        break;
                case TIOCL_PASTESEL:
                        ret = paste_selection(tty);