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authorPaolo Bonzini <pbonzini@redhat.com>2016-03-09 13:50:42 +0300
committerPaolo Bonzini <pbonzini@redhat.com>2016-03-09 13:50:42 +0300
commitab92f30875a7ec3e84644a5494febd8901e66742 (patch)
tree5254eb36b20b0d1c584c15d0bf3d6a5a9c1bb451 /drivers/tty/pty.c
parentbb9eadf0c35f2e7eb5ca6468f46ebb7473b85537 (diff)
parentb40c4892d175874d118860c8282a85ee7b64bcbb (diff)
downloadlinux-ab92f30875a7ec3e84644a5494febd8901e66742.tar.xz
Merge tag 'kvm-arm-for-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/ARM updates for 4.6 - VHE support so that we can run the kernel at EL2 on ARMv8.1 systems - PMU support for guests - 32bit world switch rewritten in C - Various optimizations to the vgic save/restore code Conflicts: include/uapi/linux/kvm.h
Diffstat (limited to 'drivers/tty/pty.c')
-rw-r--r--drivers/tty/pty.c21
1 files changed, 20 insertions, 1 deletions
diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index b3110040164a..2348fa613707 100644
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -681,7 +681,14 @@ static void pty_unix98_remove(struct tty_driver *driver, struct tty_struct *tty)
/* this is called once with whichever end is closed last */
static void pty_unix98_shutdown(struct tty_struct *tty)
{
- devpts_kill_index(tty->driver_data, tty->index);
+ struct inode *ptmx_inode;
+
+ if (tty->driver->subtype == PTY_TYPE_MASTER)
+ ptmx_inode = tty->driver_data;
+ else
+ ptmx_inode = tty->link->driver_data;
+ devpts_kill_index(ptmx_inode, tty->index);
+ devpts_del_ref(ptmx_inode);
}
static const struct tty_operations ptm_unix98_ops = {
@@ -773,6 +780,18 @@ static int ptmx_open(struct inode *inode, struct file *filp)
set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */
tty->driver_data = inode;
+ /*
+ * In the case where all references to ptmx inode are dropped and we
+ * still have /dev/tty opened pointing to the master/slave pair (ptmx
+ * is closed/released before /dev/tty), we must make sure that the inode
+ * is still valid when we call the final pty_unix98_shutdown, thus we
+ * hold an additional reference to the ptmx inode. For the same /dev/tty
+ * last close case, we also need to make sure the super_block isn't
+ * destroyed (devpts instance unmounted), before /dev/tty is closed and
+ * on its release devpts_kill_index is called.
+ */
+ devpts_add_ref(inode);
+
tty_add_file(tty, filp);
slave_inode = devpts_pty_new(inode,