FAILED: patch "[PATCH] batman-adv: tp_meter: directly shut down timer on cleanup" failed to apply to 6.6-stable tree

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x d5487249a81ea658717614009c8f46acc5b7101a
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026052842-auction-seducing-6981@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From d5487249a81ea658717614009c8f46acc5b7101a Mon Sep 17 00:00:00 2001
From: Sven Eckelmann <[email protected]>
Date: Wed, 13 May 2026 10:43:54 +0200
Subject: [PATCH] batman-adv: tp_meter: directly shut down timer on cleanup

batadv_tp_sender_cleanup() was calling timer_delete_sync() followed by timer_delete() to guard against the timer handler re-arming itself between the two calls. This double-deletion hack relied on the sending status being set to 0 to suppress re-arming.

Replace both calls with a single timer_shutdown_sync(). This function both waits for any running timer callback to complete (like timer_delete_sync()) and permanently disarms the timer so it cannot be re-armed afterwards, making re-arming prevention unconditional and self-documenting.

The re-arming property is also required because otherwise:

1. context 0 (batadv_tp_recv_ack()) checks in batadv_tp_reset_sender_timer() if sending is still 1 -> it is
2. context 1 changes in batadv_tp_sender_shutdown() sending to 0 and in this process forces the kthread to stop timer in batadv_tp_sender_cleanup()
3. context 0 continues in batadv_tp_reset_sender_timer() and rearms the timer -> but the reference for it is already gone

index a3593d104caa..1fd1526059d8 100644
@@ -401,13 +401,7 @@ static void batadv_tp_sender_cleanup(struct batadv_tp_vars *tp_vars)
 	batadv_tp_list_detach(tp_vars);
 
 	/* kill the timer and remove its reference */
-	timer_delete_sync(&tp_vars->timer);
-	/* the worker might have rearmed itself therefore we kill it again. Note
-	 * that if the worker should run again before invoking the following
-	 * timer_delete(), it would not re-arm itself once again because the status
-	 * is OFF now
-	 */
-	timer_delete(&tp_vars->timer);
+	timer_shutdown_sync(&tp_vars->timer);
 	batadv_tp_vars_put(tp_vars);
 }
 

commit d5487249a81ea658717614009c8f46acc5b7101a upstream.

batadv_tp_sender_cleanup() was calling timer_delete_sync() followed by timer_delete() to guard against the timer handler re-arming itself between the two calls. This double-deletion hack relied on the sending status being set to 0 to suppress re-arming.

Replace both calls with a single timer_shutdown_sync(). This function both waits for any running timer callback to complete (like timer_delete_sync()) and permanently disarms the timer so it cannot be re-armed afterwards, making re-arming prevention unconditional and self-documenting.

The re-arming property is also required because otherwise:

1. context 0 (batadv_tp_recv_ack()) checks in batadv_tp_reset_sender_timer() if sending is still 1 -> it is
2. context 1 changes in batadv_tp_sender_shutdown() sending to 0 and in this process forces the kthread to stop timer in batadv_tp_sender_cleanup()
3. context 0 continues in batadv_tp_reset_sender_timer() and rearms the timer -> but the reference for it is already gone

---
 net/batman-adv/tp_meter.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

index 87797969c220..bdafdec93a18 100644
@@ -400,13 +400,7 @@ static void batadv_tp_sender_cleanup(struct batadv_tp_vars *tp_vars)
 	batadv_tp_list_detach(tp_vars);
 
 	/* kill the timer and remove its reference */
-	del_timer_sync(&tp_vars->timer);
-	/* the worker might have rearmed itself therefore we kill it again. Note
-	 * that if the worker should run again before invoking the following
-	 * del_timer(), it would not re-arm itself once again because the status
-	 * is OFF now
-	 */
-	del_timer(&tp_vars->timer);
+	timer_shutdown_sync(&tp_vars->timer);
 	batadv_tp_vars_put(tp_vars);
 }
 

2.47.3