FAILED: patch "[PATCH] cpufreq: governor: fix double free in" failed to apply to 6.1-stable tree

The patch below does not apply to the 6.1-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-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 6dcf9d0064ce2f3e3dfe5755f98b93abe6a98e1e
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026040816-myth-cleft-0c71@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

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

From 6dcf9d0064ce2f3e3dfe5755f98b93abe6a98e1e Mon Sep 17 00:00:00 2001
From: Guangshuo Li <[email protected]>
Date: Wed, 1 Apr 2026 10:45:35 +0800
Subject: [PATCH] cpufreq: governor: fix double free in
cpufreq_dbs_governor_init() error path

When kobject_init_and_add() fails, cpufreq_dbs_governor_init() calls kobject_put(&dbs_data->attr_set.kobj).

The kobject release callback cpufreq_dbs_data_release() calls gov->exit(dbs_data) and kfree(dbs_data), but the current error path then calls gov->exit(dbs_data) and kfree(dbs_data) again, causing a double free.

Keep the direct kfree(dbs_data) for the gov->init() failure path, but after kobject_init_and_add() has been called, let kobject_put() handle the cleanup through cpufreq_dbs_data_release().

index acf101878733..86f35e451914 100644
@@ -468,13 +468,13 @@ int cpufreq_dbs_governor_init(struct cpufreq_policy *policy)
 	/* Failure, so roll back. */
 	pr_err("initialization failed (dbs_data kobject init error %d)\n", ret);
 
-	kobject_put(&dbs_data->attr_set.kobj);
-
 	policy->governor_data = NULL;
 
 	if (!have_governor_per_policy())
 		gov->gdbs_data = NULL;
-	gov->exit(dbs_data);
+
+	kobject_put(&dbs_data->attr_set.kobj);
+	goto free_policy_dbs_info;
 
 free_dbs_data:
 	kfree(dbs_data);

From: Liao Chang <[email protected]>

[ Upstream commit 916f13884042f615cfbfc0b42cc68dadee826f2a ]

Due to the kobject embedded in the dbs_data doest not has a release() method yet, it needs to use kfree() to free dbs_data directly when governor fails to allocate the tunner field of dbs_data.

Stable-dep-of: 6dcf9d0064ce ("cpufreq: governor: fix double free in cpufreq_dbs_governor_init() error path")

---
 drivers/cpufreq/cpufreq_governor.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

index c8bca3e77bcea..1a7fcaf39cc9b 100644
@@ -440,7 +440,7 @@ int cpufreq_dbs_governor_init(struct cpufreq_policy *policy)
 
 	ret = gov->init(dbs_data);
 	if (ret)
-		goto free_policy_dbs_info;
+		goto free_dbs_data;
 
 	/*
 	 * The sampling interval should not be less than the transition latency

@@ -475,6 +475,8 @@ int cpufreq_dbs_governor_init(struct cpufreq_policy *policy)
 	if (!have_governor_per_policy())
 		gov->gdbs_data = NULL;
 	gov->exit(dbs_data);
+
+free_dbs_data:
 	kfree(dbs_data);
 
 free_policy_dbs_info:

2.53.0

From: Guangshuo Li <[email protected]>

[ Upstream commit 6dcf9d0064ce2f3e3dfe5755f98b93abe6a98e1e ]

When kobject_init_and_add() fails, cpufreq_dbs_governor_init() calls kobject_put(&dbs_data->attr_set.kobj).

The kobject release callback cpufreq_dbs_data_release() calls gov->exit(dbs_data) and kfree(dbs_data), but the current error path then calls gov->exit(dbs_data) and kfree(dbs_data) again, causing a double free.

Keep the direct kfree(dbs_data) for the gov->init() failure path, but after kobject_init_and_add() has been called, let kobject_put() handle the cleanup through cpufreq_dbs_data_release().

---
 drivers/cpufreq/cpufreq_governor.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

index 1a7fcaf39cc9b..3ad51a9867812 100644
@@ -468,13 +468,13 @@ int cpufreq_dbs_governor_init(struct cpufreq_policy *policy)
 	/* Failure, so roll back. */
 	pr_err("initialization failed (dbs_data kobject init error %d)\n", ret);
 
-	kobject_put(&dbs_data->attr_set.kobj);
-
 	policy->governor_data = NULL;
 
 	if (!have_governor_per_policy())
 		gov->gdbs_data = NULL;
-	gov->exit(dbs_data);
+
+	kobject_put(&dbs_data->attr_set.kobj);
+	goto free_policy_dbs_info;
 
 free_dbs_data:
 	kfree(dbs_data);

2.53.0