[PATCH 5.4 086/168] vt: selection, push console lock down

Greg Kroah-Hartman
2020-03-10T12:51:49Z

From: Jiri Slaby <jslaby@suse.cz>

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>

---
drivers/staging/speakup/selection.c | 2 --
drivers/tty/vt/selection.c | 13 ++++++++++++-
drivers/tty/vt/vt.c | 2 --
3 files changed, 12 insertions(+), 5 deletions(-)

--- a/drivers/staging/speakup/selection.c
+++ b/drivers/staging/speakup/selection.c
@@ -51,9 +51,7 @@ static void __speakup_set_selection(stru
goto unref;
}

- console_lock();
set_selection_kernel(&sel, tty);
- console_unlock();

unref:
tty_kref_put(tty);
--- a/drivers/tty/vt/selection.c
+++ b/drivers/tty/vt/selection.c
@@ -181,7 +181,7 @@ int set_selection_user(const struct tioc
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
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -3046,10 +3046,8 @@ int tioclinux(struct tty_struct *tty, un
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);