Merge tag 'vfs-7.0-rc3.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs fixes from Christian Brauner:

 - kthread: consolidate kthread exit paths to prevent use-after-free

 - iomap:
    - don't mark folio uptodate if read IO has bytes pending
    - don't report direct-io retries to fserror
    - reject delalloc mappings during writeback

 - ns: tighten visibility checks

 - netfs: Fix unbuffered/DIO writes to dispatch subrequests in strict
   sequence

* tag 'vfs-7.0-rc3.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  iomap: reject delalloc mappings during writeback
  iomap: don't mark folio uptodate if read IO has bytes pending
  selftests: fix mntns iteration selftests
  nstree: tighten permission checks for listing
  nsfs: tighten permission checks for handle opening
  nsfs: tighten permission checks for ns iteration ioctls
  netfs: Fix unbuffered/DIO writes to dispatch subrequests in strict sequence
  kthread: consolidate kthread exit paths to prevent use-after-free
  iomap: don't report direct-io retries to fserror

2 files changed, 22 insertions, 1 deletions

diff --git a/include/linux/kthread.h b/include/linux/kthread.h
index c92c1149ee6e..a01a474719a7 100644
--- a/include/linux/kthread.h
+++ b/include/linux/kthread.h
@@ -7,6 +7,24 @@
 
 struct mm_struct;
 
+/* opaque kthread data */
+struct kthread;
+
+/*
+ * When "(p->flags & PF_KTHREAD)" is set the task is a kthread and will
+ * always remain a kthread.  For kthreads p->worker_private always
+ * points to a struct kthread.  For tasks that are not kthreads
+ * p->worker_private is used to point to other things.
+ *
+ * Return NULL for any task that is not a kthread.
+ */
+static inline struct kthread *tsk_is_kthread(struct task_struct *p)
+{
+	if (p->flags & PF_KTHREAD)
+		return p->worker_private;
+	return NULL;
+}
+
 __printf(4, 5)
 struct task_struct *kthread_create_on_node(int (*threadfn)(void *data),
 					   void *data,
@@ -98,9 +116,10 @@ void *kthread_probe_data(struct task_struct *k);
 int kthread_park(struct task_struct *k);
 void kthread_unpark(struct task_struct *k);
 void kthread_parkme(void);
-void kthread_exit(long result) __noreturn;
+#define kthread_exit(result) do_exit(result)
 void kthread_complete_and_exit(struct completion *, long) __noreturn;
 int kthreads_update_housekeeping(void);
+void kthread_do_exit(struct kthread *, long);
 
 int kthreadd(void *unused);
 extern struct task_struct *kthreadd_task;
diff --git a/include/linux/ns_common.h b/include/linux/ns_common.h
index 825f5865bfc5..c8e227a3f9e2 100644
--- a/include/linux/ns_common.h
+++ b/include/linux/ns_common.h
@@ -55,6 +55,8 @@ static __always_inline bool is_ns_init_id(const struct ns_common *ns)
 
 #define ns_common_free(__ns) __ns_common_free(to_ns_common((__ns)))
 
+bool may_see_all_namespaces(void);
+
 static __always_inline __must_check int __ns_ref_active_read(const struct ns_common *ns)
 {
 	return atomic_read(&ns->__ns_ref_active);