[PATCH] serport oops fix

serport - avoid calling serio_interrupt or serio_write_wakeup on unregistered
port.  Also fix memory leak which could happen if serport was left unused by
moving serio allocation down to serport_ldisc_read.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Cc: Vojtech Pavlik <vojtech@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 68 insertions, 30 deletions

diff --git a/drivers/input/serio/serport.c b/drivers/input/serio/serport.c
index 22f73683952b..f6b85222ba3d 100644
--- a/drivers/input/serio/serport.c
+++ b/drivers/input/serio/serport.c
@@ -27,11 +27,15 @@ MODULE_LICENSE("GPL");
 MODULE_ALIAS_LDISC(N_MOUSE);
 
 #define SERPORT_BUSY    1
+#define SERPORT_ACTIVE  2
+#define SERPORT_DEAD    3
 
 struct serport {
         struct tty_struct *tty;
         wait_queue_head_t wait;
         struct serio *serio;
+        struct serio_device_id id;
+        spinlock_t lock;
         unsigned long flags;
 };
 
@@ -45,11 +49,29 @@ static int serport_serio_write(struct serio *serio, unsigned char data)
         return -(serport->tty->driver->write(serport->tty, &data, 1) != 1);
 }
 
+static int serport_serio_open(struct serio *serio)
+{
+        struct serport *serport = serio->port_data;
+        unsigned long flags;
+
+        spin_lock_irqsave(&serport->lock, flags);
+        set_bit(SERPORT_ACTIVE, &serport->flags);
+        spin_unlock_irqrestore(&serport->lock, flags);
+
+        return 0;
+}
+
+
 static void serport_serio_close(struct serio *serio)
 {
         struct serport *serport = serio->port_data;
+        unsigned long flags;
+
+        spin_lock_irqsave(&serport->lock, flags);
+        clear_bit(SERPORT_ACTIVE, &serport->flags);
+        set_bit(SERPORT_DEAD, &serport->flags);
+        spin_unlock_irqrestore(&serport->lock, flags);
 
-        serport->serio->id.type = 0;
         wake_up_interruptible(&serport->wait);
 }
 
@@ -61,36 +83,21 @@ static void serport_serio_close(struct serio *serio)
 static int serport_ldisc_open(struct tty_struct *tty)
 {
         struct serport *serport;
-        struct serio *serio;
-        char name[64];
 
         if (!capable(CAP_SYS_ADMIN))
                 return -EPERM;
 
-        serport = kmalloc(sizeof(struct serport), GFP_KERNEL);
-        serio = kmalloc(sizeof(struct serio), GFP_KERNEL);
-        if (unlikely(!serport || !serio)) {
-                kfree(serport);
-                kfree(serio);
+        serport = kcalloc(1, sizeof(struct serport), GFP_KERNEL);
+        if (!serport)
                 return -ENOMEM;
-        }
 
-        memset(serport, 0, sizeof(struct serport));
-        serport->serio = serio;
-        set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
         serport->tty = tty;
-        tty->disc_data = serport;
-
-        memset(serio, 0, sizeof(struct serio));
-        strlcpy(serio->name, "Serial port", sizeof(serio->name));
-        snprintf(serio->phys, sizeof(serio->phys), "%s/serio0", tty_name(tty, name));
-        serio->id.type = SERIO_RS232;
-        serio->write = serport_serio_write;
-        serio->close = serport_serio_close;
-        serio->port_data = serport;
-
+        spin_lock_init(&serport->lock);
         init_waitqueue_head(&serport->wait);
 
+        tty->disc_data = serport;
+        set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
+
         return 0;
 }
 
@@ -100,7 +107,8 @@ static int serport_ldisc_open(struct tty_struct *tty)
 
 static void serport_ldisc_close(struct tty_struct *tty)
 {
-        struct serport *serport = (struct serport*) tty->disc_data;
+        struct serport *serport = (struct serport *) tty->disc_data;
+
         kfree(serport);
 }
 
@@ -116,9 +124,19 @@ static void serport_ldisc_close(struct tty_struct *tty)
 static void serport_ldisc_receive(struct tty_struct *tty, const unsigned char *cp, char *fp, int count)
 {
         struct serport *serport = (struct serport*) tty->disc_data;
+        unsigned long flags;
         int i;
+
+        spin_lock_irqsave(&serport->lock, flags);
+
+        if (!test_bit(SERPORT_ACTIVE, &serport->flags))
+                goto out;
+
         for (i = 0; i < count; i++)
                 serio_interrupt(serport->serio, cp[i], 0, NULL);
+
+out:
+        spin_unlock_irqrestore(&serport->lock, flags);
 }
 
 /*
@@ -141,16 +159,33 @@ static int serport_ldisc_room(struct tty_struct *tty)
 static ssize_t serport_ldisc_read(struct tty_struct * tty, struct file * file, unsigned char __user * buf, size_t nr)
 {
         struct serport *serport = (struct serport*) tty->disc_data;
+        struct serio *serio;
         char name[64];
 
         if (test_and_set_bit(SERPORT_BUSY, &serport->flags))
                 return -EBUSY;
 
+        serport->serio = serio = kcalloc(1, sizeof(struct serio), GFP_KERNEL);
+        if (!serio)
+                return -ENOMEM;
+
+        strlcpy(serio->name, "Serial port", sizeof(serio->name));
+        snprintf(serio->phys, sizeof(serio->phys), "%s/serio0", tty_name(tty, name));
+        serio->id = serport->id;
+        serio->id.type = SERIO_RS232;
+        serio->write = serport_serio_write;
+        serio->open = serport_serio_open;
+        serio->close = serport_serio_close;
+        serio->port_data = serport;
+
         serio_register_port(serport->serio);
         printk(KERN_INFO "serio: Serial port %s\n", tty_name(tty, name));
-        wait_event_interruptible(serport->wait, !serport->serio->id.type);
+
+        wait_event_interruptible(serport->wait, test_bit(SERPORT_DEAD, &serport->flags));
         serio_unregister_port(serport->serio);
+        serport->serio = NULL;
 
+        clear_bit(SERPORT_DEAD, &serport->flags);
         clear_bit(SERPORT_BUSY, &serport->flags);
 
         return 0;
@@ -163,16 +198,15 @@ static ssize_t serport_ldisc_read(struct tty_struct * tty, struct file * file, u
 static int serport_ldisc_ioctl(struct tty_struct * tty, struct file * file, unsigned int cmd, unsigned long arg)
 {
         struct serport *serport = (struct serport*) tty->disc_data;
-        struct serio *serio = serport->serio;
         unsigned long type;
 
         if (cmd == SPIOCSTYPE) {
                 if (get_user(type, (unsigned long __user *) arg))
                         return -EFAULT;
 
-                serio->id.proto = type & 0x000000ff;
-                serio->id.id    = (type & 0x0000ff00) >> 8;
-                serio->id.extra = (type & 0x00ff0000) >> 16;
+                serport->id.proto = type & 0x000000ff;
+                serport->id.id    = (type & 0x0000ff00) >> 8;
+                serport->id.extra = (type & 0x00ff0000) >> 16;
 
                 return 0;
         }
@@ -182,9 +216,13 @@ static int serport_ldisc_ioctl(struct tty_struct * tty, struct file * file, unsi
 
 static void serport_ldisc_write_wakeup(struct tty_struct * tty)
 {
-        struct serport *sp = (struct serport *) tty->disc_data;
+        struct serport *serport = (struct serport *) tty->disc_data;
+        unsigned long flags;
 
-        serio_drv_write_wakeup(sp->serio);
+        spin_lock_irqsave(&serport->lock, flags);
+        if (test_bit(SERPORT_ACTIVE, &serport->flags))
+                serio_drv_write_wakeup(serport->serio);
+        spin_unlock_irqrestore(&serport->lock, flags);
 }
 
 /*