FAILED: patch "[PATCH] net/sched: act_api: release all action references on" failed to apply to 5.15-stable tree

The patch below does not apply to the 5.15-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-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 478eb5abb51931a152abab068f8a717b7ff480fd
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026091626-turkey-huff-71e2@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

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

From 478eb5abb51931a152abab068f8a717b7ff480fd Mon Sep 17 00:00:00 2001
From: Xuanqiang Luo <[email protected]>
Date: Wed, 9 Sep 2026 15:03:35 +0800
Subject: [PATCH] net/sched: act_api: release all action references on
NEWACTION failure

When a batched RTM_NEWACTION request replaces an existing action, tcf_idr_check_alloc() takes a temporary reference on it. If a later action fails to initialize, tcf_action_destroy() uses strict release semantics to clean up the actions initialized so far. For an action bound to a filter, the strict check returns -EPERM without dropping the temporary reference.

This error also makes tcf_action_destroy() return before releasing subsequent entries. Any new action initialized between the bound action and the failing entry is leaked together with its reserved IDR slot, preventing reuse of its index.

Use tcf_idr_release() to drop each reference held by the batch without rejecting bound actions. This allows cleanup to continue through all initialized entries and preserves the module reference release when an action is destroyed. Explicit action deletion and flushing retain their separate bind-count checks.

index 37eced84dfa5..19501dc99464 100644
@@ -1200,18 +1200,13 @@ EXPORT_SYMBOL(tcf_action_exec);
 
 int tcf_action_destroy(struct tc_action *actions[], int bind)
 {
-	const struct tc_action_ops *ops;
 	struct tc_action *a;
 	int ret = 0, i;
 
 	tcf_act_for_each_action(i, a, actions) {
 		actions[i] = NULL;
-		ops = a->ops;
-		ret = __tcf_idr_release(a, bind, true);
-		if (ret == ACT_P_DELETED)
-			module_put(ops->owner);
-		else if (ret < 0)
-			return ret;
+		/* Drop our reference even if the action is still bound to a filter. */
+		ret = tcf_idr_release(a, bind);
 	}
 	return ret;
 }

From: Xuanqiang Luo <[email protected]>

[ Upstream commit 478eb5abb51931a152abab068f8a717b7ff480fd ]

When a batched RTM_NEWACTION request replaces an existing action, tcf_idr_check_alloc() takes a temporary reference on it. If a later action fails to initialize, tcf_action_destroy() uses strict release semantics to clean up the actions initialized so far. For an action bound to a filter, the strict check returns -EPERM without dropping the temporary reference.

This error also makes tcf_action_destroy() return before releasing subsequent entries. Any new action initialized between the bound action and the failing entry is leaked together with its reserved IDR slot, preventing reuse of its index.

Use tcf_idr_release() to drop each reference held by the batch without rejecting bound actions. This allows cleanup to continue through all initialized entries and preserves the module reference release when an action is destroyed. Explicit action deletion and flushing retain their separate bind-count checks.

---
 net/sched/act_api.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

index 20944a2e162e7..64fc0e19ac40a 100644
@@ -798,19 +798,14 @@ EXPORT_SYMBOL(tcf_action_exec);
 
 int tcf_action_destroy(struct tc_action *actions[], int bind)
 {
-	const struct tc_action_ops *ops;
 	struct tc_action *a;
 	int ret = 0, i;
 
 	for (i = 0; i < TCA_ACT_MAX_PRIO && actions[i]; i++) {
 		a = actions[i];
 		actions[i] = NULL;
-		ops = a->ops;
-		ret = __tcf_idr_release(a, bind, true);
-		if (ret == ACT_P_DELETED)
-			module_put(ops->owner);
-		else if (ret < 0)
-			return ret;
+		/* Drop our reference even if the action is still bound to a filter. */
+		ret = tcf_idr_release(a, bind);
 	}
 	return ret;
 }

2.53.0