5 files changed, 49 insertions, 2 deletions

diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h
index 0cd9f10423fb..a3fda9f024c3 100644
--- a/include/linux/sched/mm.h
+++ b/include/linux/sched/mm.h
@@ -49,6 +49,27 @@ static inline void mmdrop(struct mm_struct *mm)
 		__mmdrop(mm);
 }
 
+/*
+ * This has to be called after a get_task_mm()/mmget_not_zero()
+ * followed by taking the mmap_sem for writing before modifying the
+ * vmas or anything the coredump pretends not to change from under it.
+ *
+ * NOTE: find_extend_vma() called from GUP context is the only place
+ * that can modify the "mm" (notably the vm_start/end) under mmap_sem
+ * for reading and outside the context of the process, so it is also
+ * the only case that holds the mmap_sem for reading that must call
+ * this function. Generally if the mmap_sem is hold for reading
+ * there's no need of this check after get_task_mm()/mmget_not_zero().
+ *
+ * This function can be obsoleted and the check can be removed, after
+ * the coredump code will hold the mmap_sem for writing before
+ * invoking the ->core_dump methods.
+ */
+static inline bool mmget_still_valid(struct mm_struct *mm)
+{
+	return likely(!mm->core_state);
+}
+
 /**
  * mmget() - Pin the address space associated with a &struct mm_struct.
  * @mm: The address space to pin.
diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h
index ae5655197698..e412c092c1e8 100644
--- a/include/linux/sched/signal.h
+++ b/include/linux/sched/signal.h
@@ -418,10 +418,20 @@ static inline void set_restore_sigmask(void)
 	set_thread_flag(TIF_RESTORE_SIGMASK);
 	WARN_ON(!test_thread_flag(TIF_SIGPENDING));
 }
+
+static inline void clear_tsk_restore_sigmask(struct task_struct *tsk)
+{
+	clear_tsk_thread_flag(tsk, TIF_RESTORE_SIGMASK);
+}
+
 static inline void clear_restore_sigmask(void)
 {
 	clear_thread_flag(TIF_RESTORE_SIGMASK);
 }
+static inline bool test_tsk_restore_sigmask(struct task_struct *tsk)
+{
+	return test_tsk_thread_flag(tsk, TIF_RESTORE_SIGMASK);
+}
 static inline bool test_restore_sigmask(void)
 {
 	return test_thread_flag(TIF_RESTORE_SIGMASK);
@@ -439,6 +449,10 @@ static inline void set_restore_sigmask(void)
 	current->restore_sigmask = true;
 	WARN_ON(!test_thread_flag(TIF_SIGPENDING));
 }
+static inline void clear_tsk_restore_sigmask(struct task_struct *tsk)
+{
+	tsk->restore_sigmask = false;
+}
 static inline void clear_restore_sigmask(void)
 {
 	current->restore_sigmask = false;
@@ -447,6 +461,10 @@ static inline bool test_restore_sigmask(void)
 {
 	return current->restore_sigmask;
 }
+static inline bool test_tsk_restore_sigmask(struct task_struct *tsk)
+{
+	return tsk->restore_sigmask;
+}
 static inline bool test_and_clear_restore_sigmask(void)
 {
 	if (!current->restore_sigmask)
diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h
index 2e97a2227045..f1227f2c38a4 100644
--- a/include/linux/sched/task.h
+++ b/include/linux/sched/task.h
@@ -76,6 +76,7 @@ extern void exit_itimers(struct signal_struct *);
 extern long _do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *, unsigned long);
 extern long do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *);
 struct task_struct *fork_idle(int);
+struct mm_struct *copy_init_mm(void);
 extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
 extern long kernel_wait4(pid_t, int __user *, int, struct rusage *);
 
diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h
index 57c7ed3fe465..cfc0a89a7159 100644
--- a/include/linux/sched/topology.h
+++ b/include/linux/sched/topology.h
@@ -76,8 +76,8 @@ struct sched_domain_shared {
 
 struct sched_domain {
 	/* These fields must be setup */
-	struct sched_domain *parent;	/* top domain must be null terminated */
-	struct sched_domain *child;	/* bottom domain must be null terminated */
+	struct sched_domain __rcu *parent;	/* top domain must be null terminated */
+	struct sched_domain __rcu *child;	/* bottom domain must be null terminated */
 	struct sched_group *groups;	/* the balancing groups of the domain */
 	unsigned long min_interval;	/* Minimum balance interval ms */
 	unsigned long max_interval;	/* Maximum balance interval ms */
diff --git a/include/linux/sched/user.h b/include/linux/sched/user.h
index c7b5f86b91a1..468d2565a9fe 100644
--- a/include/linux/sched/user.h
+++ b/include/linux/sched/user.h
@@ -31,6 +31,13 @@ struct user_struct {
 	atomic_long_t pipe_bufs;  /* how many pages are allocated in pipe buffers */
 
 #ifdef CONFIG_KEYS
+	/*
+	 * These pointers can only change from NULL to a non-NULL value once.
+	 * Writes are protected by key_user_keyring_mutex.
+	 * Unlocked readers should use READ_ONCE() unless they know that
+	 * install_user_keyrings() has been called successfully (which sets
+	 * these members to non-NULL values, preventing further modifications).
+	 */
 	struct key *uid_keyring;	/* UID specific keyring */
 	struct key *session_keyring;	/* UID's default session keyring */
 #endif