Merge tag 'driver-core-6.17-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core

Pull driver core fixes from Danilo Krummrich:

 - Fix UAF in cgroup pressure polling by using kernfs_get_active_of()
   to prevent operations on released file descriptors

 - Fix unresolved intra-doc link in the documentation of struct Device
   when CONFIG_DRM != y

 - Update the DMA Rust MAINTAINERS entry

* tag 'driver-core-6.17-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core:
  MAINTAINERS: Update the DMA Rust entry
  kernfs: Fix UAF in polling when open file is released
  rust: device: fix unresolved link to drm::Device

MAINTAINERS

@@ -7238,15 +7238,15 @@ F:	include/linux/swiotlb.h
 F:	kernel/dma/
 
 DMA MAPPING HELPERS DEVICE DRIVER API [RUST]
-M:	Abdiel Janulgue <abdiel.janulgue@gmail.com>
 M:	Danilo Krummrich <dakr@kernel.org>
+R:	Abdiel Janulgue <abdiel.janulgue@gmail.com>
 R:	Daniel Almeida <daniel.almeida@collabora.com>
 R:	Robin Murphy <robin.murphy@arm.com>
 R:	Andreas Hindborg <a.hindborg@kernel.org>
 L:	rust-for-linux@vger.kernel.org
 S:	Supported
 W:	https://rust-for-linux.com
-T:	git https://github.com/Rust-for-Linux/linux.git alloc-next
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core.git
 F:	rust/helpers/dma.c
 F:	rust/kernel/dma.rs
 F:	samples/rust/rust_dma.rs

fs/kernfs/file.c

@@ -70,6 +70,24 @@ static struct kernfs_open_node *of_on(struct kernfs_open_file *of)
 					 !list_empty(&of->list));
 }
 
+/* Get active reference to kernfs node for an open file */
+static struct kernfs_open_file *kernfs_get_active_of(struct kernfs_open_file *of)
+{
+	/* Skip if file was already released */
+	if (unlikely(of->released))
+		return NULL;
+
+	if (!kernfs_get_active(of->kn))
+		return NULL;
+
+	return of;
+}
+
+static void kernfs_put_active_of(struct kernfs_open_file *of)
+{
+	return kernfs_put_active(of->kn);
+}
+
 /**
  * kernfs_deref_open_node_locked - Get kernfs_open_node corresponding to @kn
  *
@@ -139,7 +157,7 @@ static void kernfs_seq_stop_active(struct seq_file *sf, void *v)
 
 	if (ops->seq_stop)
 		ops->seq_stop(sf, v);
-	kernfs_put_active(of->kn);
+	kernfs_put_active_of(of);
 }
 
 static void *kernfs_seq_start(struct seq_file *sf, loff_t *ppos)
@@ -152,7 +170,7 @@ static void *kernfs_seq_start(struct seq_file *sf, loff_t *ppos)
 	 * the ops aren't called concurrently for the same open file.
 	 */
 	mutex_lock(&of->mutex);
-	if (!kernfs_get_active(of->kn))
+	if (!kernfs_get_active_of(of))
 		return ERR_PTR(-ENODEV);
 
 	ops = kernfs_ops(of->kn);
@@ -238,7 +256,7 @@ static ssize_t kernfs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
 	 * the ops aren't called concurrently for the same open file.
 	 */
 	mutex_lock(&of->mutex);
-	if (!kernfs_get_active(of->kn)) {
+	if (!kernfs_get_active_of(of)) {
 		len = -ENODEV;
 		mutex_unlock(&of->mutex);
 		goto out_free;
@@ -252,7 +270,7 @@ static ssize_t kernfs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter)
 	else
 		len = -EINVAL;
 
-	kernfs_put_active(of->kn);
+	kernfs_put_active_of(of);
 	mutex_unlock(&of->mutex);
 
 	if (len < 0)
@@ -323,7 +341,7 @@ static ssize_t kernfs_fop_write_iter(struct kiocb *iocb, struct iov_iter *iter)
 	 * the ops aren't called concurrently for the same open file.
 	 */
 	mutex_lock(&of->mutex);
-	if (!kernfs_get_active(of->kn)) {
+	if (!kernfs_get_active_of(of)) {
 		mutex_unlock(&of->mutex);
 		len = -ENODEV;
 		goto out_free;
@@ -335,7 +353,7 @@ static ssize_t kernfs_fop_write_iter(struct kiocb *iocb, struct iov_iter *iter)
 	else
 		len = -EINVAL;
 
-	kernfs_put_active(of->kn);
+	kernfs_put_active_of(of);
 	mutex_unlock(&of->mutex);
 
 	if (len > 0)
@@ -357,13 +375,13 @@ static void kernfs_vma_open(struct vm_area_struct *vma)
 	if (!of->vm_ops)
 		return;
 
-	if (!kernfs_get_active(of->kn))
+	if (!kernfs_get_active_of(of))
 		return;
 
 	if (of->vm_ops->open)
 		of->vm_ops->open(vma);
 
-	kernfs_put_active(of->kn);
+	kernfs_put_active_of(of);
 }
 
 static vm_fault_t kernfs_vma_fault(struct vm_fault *vmf)
@@ -375,14 +393,14 @@ static vm_fault_t kernfs_vma_fault(struct vm_fault *vmf)
 	if (!of->vm_ops)
 		return VM_FAULT_SIGBUS;
 
-	if (!kernfs_get_active(of->kn))
+	if (!kernfs_get_active_of(of))
 		return VM_FAULT_SIGBUS;
 
 	ret = VM_FAULT_SIGBUS;
 	if (of->vm_ops->fault)
 		ret = of->vm_ops->fault(vmf);
 
-	kernfs_put_active(of->kn);
+	kernfs_put_active_of(of);
 	return ret;
 }
 
@@ -395,7 +413,7 @@ static vm_fault_t kernfs_vma_page_mkwrite(struct vm_fault *vmf)
 	if (!of->vm_ops)
 		return VM_FAULT_SIGBUS;
 
-	if (!kernfs_get_active(of->kn))
+	if (!kernfs_get_active_of(of))
 		return VM_FAULT_SIGBUS;
 
 	ret = 0;
@@ -404,7 +422,7 @@ static vm_fault_t kernfs_vma_page_mkwrite(struct vm_fault *vmf)
 	else
 		file_update_time(file);
 
-	kernfs_put_active(of->kn);
+	kernfs_put_active_of(of);
 	return ret;
 }
 
@@ -418,14 +436,14 @@ static int kernfs_vma_access(struct vm_area_struct *vma, unsigned long addr,
 	if (!of->vm_ops)
 		return -EINVAL;
 
-	if (!kernfs_get_active(of->kn))
+	if (!kernfs_get_active_of(of))
 		return -EINVAL;
 
 	ret = -EINVAL;
 	if (of->vm_ops->access)
 		ret = of->vm_ops->access(vma, addr, buf, len, write);
 
-	kernfs_put_active(of->kn);
+	kernfs_put_active_of(of);
 	return ret;
 }
 
@@ -455,7 +473,7 @@ static int kernfs_fop_mmap(struct file *file, struct vm_area_struct *vma)
 	mutex_lock(&of->mutex);
 
 	rc = -ENODEV;
-	if (!kernfs_get_active(of->kn))
+	if (!kernfs_get_active_of(of))
 		goto out_unlock;
 
 	ops = kernfs_ops(of->kn);
@@ -490,7 +508,7 @@ static int kernfs_fop_mmap(struct file *file, struct vm_area_struct *vma)
 	}
 	vma->vm_ops = &kernfs_vm_ops;
 out_put:
-	kernfs_put_active(of->kn);
+	kernfs_put_active_of(of);
 out_unlock:
 	mutex_unlock(&of->mutex);
 
@@ -852,7 +870,7 @@ static __poll_t kernfs_fop_poll(struct file *filp, poll_table *wait)
 	struct kernfs_node *kn = kernfs_dentry_node(filp->f_path.dentry);
 	__poll_t ret;
 
-	if (!kernfs_get_active(kn))
+	if (!kernfs_get_active_of(of))
 		return DEFAULT_POLLMASK|EPOLLERR|EPOLLPRI;
 
 	if (kn->attr.ops->poll)
@@ -860,7 +878,7 @@ static __poll_t kernfs_fop_poll(struct file *filp, poll_table *wait)
 	else
 		ret = kernfs_generic_poll(of, wait);
 
-	kernfs_put_active(kn);
+	kernfs_put_active_of(of);
 	return ret;
 }
 
@@ -875,7 +893,7 @@ static loff_t kernfs_fop_llseek(struct file *file, loff_t offset, int whence)
 	 * the ops aren't called concurrently for the same open file.
 	 */
 	mutex_lock(&of->mutex);
-	if (!kernfs_get_active(of->kn)) {
+	if (!kernfs_get_active_of(of)) {
 		mutex_unlock(&of->mutex);
 		return -ENODEV;
 	}
@@ -886,7 +904,7 @@ static loff_t kernfs_fop_llseek(struct file *file, loff_t offset, int whence)
 	else
 		ret = generic_file_llseek(file, offset, whence);
 
-	kernfs_put_active(of->kn);
+	kernfs_put_active_of(of);
 	mutex_unlock(&of->mutex);
 	return ret;
 }

rust/kernel/device.rs

@@ -138,7 +138,9 @@
 /// }
 /// ```
 ///
-/// An example for a class device implementation is [`drm::Device`].
+/// An example for a class device implementation is
+#[cfg_attr(CONFIG_DRM = "y", doc = "[`drm::Device`](kernel::drm::Device).")]
+#[cfg_attr(not(CONFIG_DRM = "y"), doc = "`drm::Device`.")]
 ///
 /// # Invariants
 ///
@@ -151,7 +153,6 @@
 /// dropped from any thread.
 ///
 /// [`AlwaysRefCounted`]: kernel::types::AlwaysRefCounted
-/// [`drm::Device`]: kernel::drm::Device
 /// [`impl_device_context_deref`]: kernel::impl_device_context_deref
 /// [`pci::Device`]: kernel::pci::Device
 /// [`platform::Device`]: kernel::platform::Device