FAILED: patch "[PATCH] batman-adv: tp_meter: fix tp_num leak on kmalloc failure" failed to apply to 6.18-stable tree

FAILED: patch "[PATCH] batman-adv: tp_meter: fix tp_num leak on kmalloc failure" failed to apply to 6.18-stable tree

[gregkh]

The patch below does not apply to the 6.18-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 <stable@vger.kernel.org>.

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-6.18.y
git checkout FETCH_HEAD
git cherry-pick -x ce425dd05d0fe7594930a0fb103634f35ac47bb6
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026051519-award-matron-543d@gregkh' --subject-prefix 'PATCH 6.18.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

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

From ce425dd05d0fe7594930a0fb103634f35ac47bb6 Mon Sep 17 00:00:00 2001
From: Sven Eckelmann <sven@narfation.org>
Date: Wed, 6 May 2026 22:20:49 +0200
Subject: [PATCH] batman-adv: tp_meter: fix tp_num leak on kmalloc failure

When batadv_tp_start() or batadv_tp_init_recv() fail to allocate a new
tp_vars object, the previously incremented bat_priv->tp_num counter is
never decremented. This causes tp_num to drift upward on each allocation
failure. Since only BATADV_TP_MAX_NUM sessions can be started and the count
is never reduced for these failed allocations, it causes to an exhaustion
of throughput meter sessions. In worst case, no new throughput meter
session can be started until the mesh interface is removed.

The error handling must decrement tp_num releasing the lock and aborting
the creation of an throughput meter session

Cc: stable@kernel.org
Fixes: 33a3bb4a3345 ("batman-adv: throughput meter implementation")
Signed-off-by: Sven Eckelmann <sven@narfation.org>

diff --git a/net/batman-adv/tp_meter.c b/net/batman-adv/tp_meter.c
index 58ca59a2799e..066c76113fc4 100644
--- a/net/batman-adv/tp_meter.c
+++ b/net/batman-adv/tp_meter.c
@@ -994,6 +994,7 @@ void batadv_tp_start(struct batadv_priv *bat_priv, const u8 *dst,
 
 	tp_vars = kmalloc_obj(*tp_vars, GFP_ATOMIC);
 	if (!tp_vars) {
+		atomic_dec(&bat_priv->tp_num);
 		spin_unlock_bh(&bat_priv->tp_list_lock);
 		batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
 			   "Meter: %s cannot allocate list elements\n",
@@ -1366,8 +1367,10 @@ batadv_tp_init_recv(struct batadv_priv *bat_priv,
 	}
 
 	tp_vars = kmalloc_obj(*tp_vars, GFP_ATOMIC);
-	if (!tp_vars)
+	if (!tp_vars) {
+		atomic_dec(&bat_priv->tp_num);
 		goto out_unlock;
+	}
 
 	ether_addr_copy(tp_vars->other_end, icmp->orig);
 	tp_vars->role = BATADV_TP_RECEIVER;

[PATCH 6.18.y] batman-adv: tp_meter: fix tp_num leak on kmalloc failure

[Sven Eckelmann]

commit ce425dd05d0fe7594930a0fb103634f35ac47bb6 upstream.

When batadv_tp_start() or batadv_tp_init_recv() fail to allocate a new
tp_vars object, the previously incremented bat_priv->tp_num counter is
never decremented. This causes tp_num to drift upward on each allocation
failure. Since only BATADV_TP_MAX_NUM sessions can be started and the count
is never reduced for these failed allocations, it causes to an exhaustion
of throughput meter sessions. In worst case, no new throughput meter
session can be started until the mesh interface is removed.

The error handling must decrement tp_num releasing the lock and aborting
the creation of an throughput meter session

Cc: stable@kernel.org
Fixes: 33a3bb4a3345 ("batman-adv: throughput meter implementation")
[ Context ]
Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
 net/batman-adv/tp_meter.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/batman-adv/tp_meter.c b/net/batman-adv/tp_meter.c
index 350b149e48be..0ae7887ff2db 100644
--- a/net/batman-adv/tp_meter.c
+++ b/net/batman-adv/tp_meter.c
@@ -969,6 +969,7 @@ void batadv_tp_start(struct batadv_priv *bat_priv, const u8 *dst,
 
 	tp_vars = kmalloc(sizeof(*tp_vars), GFP_ATOMIC);
 	if (!tp_vars) {
+		atomic_dec(&bat_priv->tp_num);
 		spin_unlock_bh(&bat_priv->tp_list_lock);
 		batadv_dbg(BATADV_DBG_TP_METER, bat_priv,
 			   "Meter: %s cannot allocate list elements\n",
@@ -1344,8 +1345,10 @@ batadv_tp_init_recv(struct batadv_priv *bat_priv,
 	}
 
 	tp_vars = kmalloc(sizeof(*tp_vars), GFP_ATOMIC);
-	if (!tp_vars)
+	if (!tp_vars) {
+		atomic_dec(&bat_priv->tp_num);
 		goto out_unlock;
+	}
 
 	ether_addr_copy(tp_vars->other_end, icmp->orig);
 	tp_vars->role = BATADV_TP_RECEIVER;
-- 
2.47.3