treewide: Convert del_timer*() to timer_shutdown*()

Due to several bugs caused by timers being re-armed after they are
shutdown and just before they are freed, a new state of timers was added
called "shutdown".  After a timer is set to this state, then it can no
longer be re-armed.

The following script was run to find all the trivial locations where
del_timer() or del_timer_sync() is called in the same function that the
object holding the timer is freed.  It also ignores any locations where
the timer->function is modified between the del_timer*() and the free(),
as that is not considered a "trivial" case.

This was created by using a coccinelle script and the following
commands:

    $ cat timer.cocci
    @@
    expression ptr, slab;
    identifier timer, rfield;
    @@
    (
    -       del_timer(&ptr->timer);
    +       timer_shutdown(&ptr->timer);
    |
    -       del_timer_sync(&ptr->timer);
    +       timer_shutdown_sync(&ptr->timer);
    )
      ... when strict
          when != ptr->timer
    (
            kfree_rcu(ptr, rfield);
    |
            kmem_cache_free(slab, ptr);
    |
            kfree(ptr);
    )

    $ spatch timer.cocci . > /tmp/t.patch
    $ patch -p1 < /tmp/t.patch

Link: https://lore.kernel.org/lkml/20221123201306.823305113@linutronix.de/
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Pavel Machek <pavel@ucw.cz> [ LED ]
Acked-by: Kalle Valo <kvalo@kernel.org> [ wireless ]
Acked-by: Paolo Abeni <pabeni@redhat.com> [ networking ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/drivers/atm/idt77252.c b/drivers/atm/idt77252.c
index 681cb3786794..eec0cc2144e0 100644
--- a/drivers/atm/idt77252.c
+++ b/drivers/atm/idt77252.c
@@ -2213,7 +2213,7 @@ idt77252_init_ubr(struct idt77252_dev *card, struct vc_map *vc,
 	}
 	spin_unlock_irqrestore(&vc->lock, flags);
 	if (est) {
-		del_timer_sync(&est->timer);
+		timer_shutdown_sync(&est->timer);
 		kfree(est);
 	}
 
@@ -2530,7 +2530,7 @@ done:
 		vc->tx_vcc = NULL;
 
 		if (vc->estimator) {
-			del_timer(&vc->estimator->timer);
+			timer_shutdown(&vc->estimator->timer);
 			kfree(vc->estimator);
 			vc->estimator = NULL;
 		}
@@ -3752,7 +3752,7 @@ static void __exit idt77252_exit(void)
 		card = idt77252_chain;
 		dev = card->atmdev;
 		idt77252_chain = card->next;
-		del_timer_sync(&card->tst_timer);
+		timer_shutdown_sync(&card->tst_timer);
 
 		if (dev->phy->stop)
 			dev->phy->stop(dev);