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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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