[PATCH 0/2] Add calls to mutex_destroy in virtio_balloon and virtio_mem

[PATCH 0/2] Add calls to mutex_destroy in virtio_balloon and virtio_mem

[Maurice Hieronymus]

In [1] it is pointed out that each mutex_init call should have a
corresponding call to mutex_destroy; otherwise, it is considered a bug.

This patch adds the calls to mutex_destroy in virtio_balloon as well
as virtio_mem.

Link: https://lists.kernelnewbies.org/pipermail/kernelnewbies/2025-November/023493.html [1]

Maurice Hieronymus (2):
  virtio-balloon: Destroy mutex before freeing virtio_balloon
  virtio-mem: Destroy mutex before freeing virtio_mem

 drivers/virtio/virtio_balloon.c | 2 ++
 drivers/virtio/virtio_mem.c     | 2 ++
 2 files changed, 4 insertions(+)


base-commit: d13f3ac64efb868d09cb2726b1e84929afe90235
-- 
2.50.1

[PATCH 1/2] virtio-balloon: Destroy mutex before freeing virtio_balloon

[Maurice Hieronymus]

Add a call to mutex_destroy in the error code path as well as in the
virtballoon_remove code path.

Signed-off-by: Maurice Hieronymus <mhi@mailbox.org>
---
 drivers/virtio/virtio_balloon.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 1b93d8c64361..078b87720a0d 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -1094,6 +1094,7 @@ static int virtballoon_probe(struct virtio_device *vdev)
 out_del_vqs:
 	vdev->config->del_vqs(vdev);
 out_free_vb:
+	mutex_destroy(&vb->balloon_lock);
 	kfree(vb);
 out:
 	return err;
@@ -1138,6 +1139,7 @@ static void virtballoon_remove(struct virtio_device *vdev)
 	}
 
 	remove_common(vb);
+	mutex_destroy(&vb->balloon_lock);
 	kfree(vb);
 }
 
-- 
2.50.1

[PATCH 2/2] virtio-mem: Destroy mutex before freeing virtio_mem

[Maurice Hieronymus]

Add a call to mutex_destroy in the error code path as well as in the
virtio_mem_remove code path.

Signed-off-by: Maurice Hieronymus <mhi@mailbox.org>
---
 drivers/virtio/virtio_mem.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
index 1688ecd69a04..8107988dcb05 100644
--- a/drivers/virtio/virtio_mem.c
+++ b/drivers/virtio/virtio_mem.c
@@ -2975,6 +2975,7 @@ static int virtio_mem_probe(struct virtio_device *vdev)
 out_del_vq:
 	vdev->config->del_vqs(vdev);
 out_free_vm:
+	mutex_destroy(&vm->hotplug_mutex);
 	kfree(vm);
 	vdev->priv = NULL;
 
@@ -3067,6 +3068,7 @@ static void virtio_mem_remove(struct virtio_device *vdev)
 	virtio_reset_device(vdev);
 	vdev->config->del_vqs(vdev);
 
+	mutex_destroy(&vm->hotplug_mutex);
 	kfree(vm);
 	vdev->priv = NULL;
 }
-- 
2.50.1

Re: [PATCH 0/2] Add calls to mutex_destroy in virtio_balloon and virtio_mem

[David Hildenbrand (Red Hat)]

On 11/23/25 18:57, Maurice Hieronymus wrote:
> In [1] it is pointed out that each mutex_init call should have a
> corresponding call to mutex_destroy; otherwise, it is considered a bug.

IIUC, mutex_destroy() only ever does something during with 
CONFIG_DEBUG_MUTEXES. And there, it performs mostly sanity checks (so 
it's not some missed memory freeing etc).

I wonder whether we should still ad Fixes tags.

-- 
Cheers

David

Re: [PATCH 1/2] virtio-balloon: Destroy mutex before freeing virtio_balloon

[David Hildenbrand (Red Hat)]

On 11/23/25 18:57, Maurice Hieronymus wrote:
> Add a call to mutex_destroy in the error code path as well as in the
> virtballoon_remove code path.
> 
> Signed-off-by: Maurice Hieronymus <mhi@mailbox.org>

Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>

-- 
Cheers

David

Re: [PATCH 2/2] virtio-mem: Destroy mutex before freeing virtio_mem

[David Hildenbrand (Red Hat)]

On 11/23/25 18:57, Maurice Hieronymus wrote:
> Add a call to mutex_destroy in the error code path as well as in the
> virtio_mem_remove code path.
> 
> Signed-off-by: Maurice Hieronymus <mhi@mailbox.org>
> ---

Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>

-- 
Cheers

David