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, 2 insertions, 2 deletions

diff --git a/net/bridge/br_multicast_eht.c b/net/bridge/br_multicast_eht.c
index f91c071d1608..c126aa4e7551 100644
--- a/net/bridge/br_multicast_eht.c
+++ b/net/bridge/br_multicast_eht.c
@@ -142,7 +142,7 @@ static void br_multicast_destroy_eht_set_entry(struct net_bridge_mcast_gc *gc)
 	set_h = container_of(gc, struct net_bridge_group_eht_set_entry, mcast_gc);
 	WARN_ON(!RB_EMPTY_NODE(&set_h->rb_node));
 
-	del_timer_sync(&set_h->timer);
+	timer_shutdown_sync(&set_h->timer);
 	kfree(set_h);
 }
 
@@ -154,7 +154,7 @@ static void br_multicast_destroy_eht_set(struct net_bridge_mcast_gc *gc)
 	WARN_ON(!RB_EMPTY_NODE(&eht_set->rb_node));
 	WARN_ON(!RB_EMPTY_ROOT(&eht_set->entry_tree));
 
-	del_timer_sync(&eht_set->timer);
+	timer_shutdown_sync(&eht_set->timer);
 	kfree(eht_set);
 }