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Subject[PATCH 4.14 104/126] vt: selection, push console lock down
Date
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/tty/vt/selection.c | 13 ++++++++++++-
drivers/tty/vt/vt.c | 2 --
2 files changed, 12 insertions(+), 3 deletions(-)

--- a/drivers/tty/vt/selection.c
+++ b/drivers/tty/vt/selection.c
@@ -157,7 +157,7 @@ static int store_utf8(u16 c, char *p)
* The entire selection process is managed under the console_lock. It's
* a lot under the lock but its hardly a performance path
*/
-int set_selection(const struct tiocl_selection __user *sel, struct tty_struct *tty)
+static int __set_selection(const struct tiocl_selection __user *sel, struct tty_struct *tty)
{
struct vc_data *vc = vc_cons[fg_console].d;
int sel_mode, new_sel_start, new_sel_end, spc;
@@ -333,6 +333,17 @@ unlock:
return ret;
}

+int set_selection(const struct tiocl_selection __user *v, struct tty_struct *tty)
+{
+ int ret;
+
+ console_lock();
+ ret = __set_selection(v, tty);
+ console_unlock();
+
+ return ret;
+}
+
/* Insert the contents of the selection buffer into the
* queue of the tty associated with the current console.
* Invoked by ioctl().
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -2688,9 +2688,7 @@ int tioclinux(struct tty_struct *tty, un
switch (type)
{
case TIOCL_SETSEL:
- console_lock();
ret = set_selection((struct tiocl_selection __user *)(p+1), tty);
- console_unlock();
break;
case TIOCL_PASTESEL:
ret = paste_selection(tty);

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