[tip: locking/urgent] futex: Clean up the redundant exit/exec functions

The following commit has been merged into the locking/urgent branch of tip:

Commit-ID:     221b62e97811845340c888993ae049467399d2b5
Gitweb:        https://git.kernel.org/tip/221b62e97811845340c888993ae049467399d2b5
Author:        Thomas Gleixner <[email protected]>
AuthorDate:    Fri, 07 Aug 2026 17:07:17 +02:00
Committer:     Thomas Gleixner <[email protected]>
CommitterDate: Sun, 16 Aug 2026 00:16:32 +02:00

futex: Clean up the redundant exit/exec functions

futex_exit_release() and futex_exec_release() are identical now. That means
also exit_mm_release() and exec_mm_release() are identical.

Consolidate the whole lot and remove the redundant copies.

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Kyle Zeng <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
---
 fs/exec.c                |  2 +-
 include/linux/futex.h    |  6 ++----
 include/linux/sched/mm.h | 10 ++++++----
 kernel/exit.c            |  2 +-
 kernel/fork.c            | 10 ++--------
 kernel/futex/core.c      | 37 +++++++++++++++++--------------------
 6 files changed, 29 insertions(+), 38 deletions(-)

diff --git a/fs/exec.c b/fs/exec.c
index d01523d..22df492 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -856,7 +856,7 @@ static int exec_mmap(struct linux_binprm *bprm)
 	tsk = current;
 	old_mm = current->mm;
 	/* Clean up futexes and release the mm */
-	exec_mm_release(tsk, old_mm);
+	mm_exit_exec_release(tsk, old_mm);
 
 	ret = down_write_killable(&tsk->signal->exec_update_lock);
 	if (ret)
diff --git a/include/linux/futex.h b/include/linux/futex.h
index 51d5faa..18ed18d 100644
--- a/include/linux/futex.h
+++ b/include/linux/futex.h
@@ -71,8 +71,7 @@ static inline void futex_init_task(struct task_struct *tsk)
 }
 
 void futex_exit_recursive(struct task_struct *tsk);
-void futex_exit_release(struct task_struct *tsk);
-void futex_exec_release(struct task_struct *tsk);
+void futex_exit_exec_release(struct task_struct *tsk);
 void futex_exec_done(struct task_struct *tsk);
 
 long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
@@ -90,8 +89,7 @@ static inline int futex_hash_free(struct mm_struct *mm) { return 0; }
 #else  /* CONFIG_FUTEX */
 static inline void futex_init_task(struct task_struct *tsk) { }
 static inline void futex_exit_recursive(struct task_struct *tsk) { }
-static inline void futex_exit_release(struct task_struct *tsk) { }
-static inline void futex_exec_release(struct task_struct *tsk) { }
+static inline void futex_exit_exec_release(struct task_struct *tsk) { }
 static inline void futex_exec_done(struct task_struct *tsk) { }
 static inline long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
 			    u32 __user *uaddr2, u32 val2, u32 val3)
diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h
index 95d0040..7fe7dfd 100644
--- a/include/linux/sched/mm.h
+++ b/include/linux/sched/mm.h
@@ -155,10 +155,12 @@ extern struct mm_struct *get_task_mm(struct task_struct *task);
  * succeeds.
  */
 extern struct mm_struct *mm_access(struct task_struct *task, unsigned int mode);
-/* Remove the current tasks stale references to the old mm_struct on exit() */
-extern void exit_mm_release(struct task_struct *, struct mm_struct *);
-/* Remove the current tasks stale references to the old mm_struct on exec() */
-extern void exec_mm_release(struct task_struct *, struct mm_struct *);
+
+/*
+ * Remove the current tasks stale references to the old mm_struct on exit() and
+ * exec(). Cleans up futexes as well.
+ */
+extern void mm_exit_exec_release(struct task_struct *, struct mm_struct *);
 
 #ifdef CONFIG_MEMCG
 extern void mm_update_next_owner(struct mm_struct *mm);
diff --git a/kernel/exit.c b/kernel/exit.c
index 2c0b1c0..adf93b9 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -582,7 +582,7 @@ static void exit_mm(void)
 {
 	struct mm_struct *mm = current->mm;
 
-	exit_mm_release(current, mm);
+	mm_exit_exec_release(current, mm);
 	if (!mm)
 		return;
 
diff --git a/kernel/fork.c b/kernel/fork.c
index f0e2e13..7c6918b 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1502,15 +1502,9 @@ static void mm_release(struct task_struct *tsk, struct mm_struct *mm)
 		complete_vfork_done(tsk);
 }
 
-void exit_mm_release(struct task_struct *tsk, struct mm_struct *mm)
+void mm_exit_exec_release(struct task_struct *tsk, struct mm_struct *mm)
 {
-	futex_exit_release(tsk);
-	mm_release(tsk, mm);
-}
-
-void exec_mm_release(struct task_struct *tsk, struct mm_struct *mm)
-{
-	futex_exec_release(tsk);
+	futex_exit_exec_release(tsk);
 	mm_release(tsk, mm);
 }
 
diff --git a/kernel/futex/core.c b/kernel/futex/core.c
index 3c1562d..2d1dbde 100644
--- a/kernel/futex/core.c
+++ b/kernel/futex/core.c
@@ -1537,32 +1537,29 @@ static void futex_cleanup_end(struct task_struct *tsk)
 	mutex_unlock(&tsk->futex.exit_mutex);
 }
 
-void futex_exit_release(struct task_struct *tsk)
+/*
+ * Invoked from mm_exit_exec_release() to cleanup the robust lists and pi state
+ * of the outgoing task.
+ *
+ * exec() makes it interesting for futexes because the TID of the task stays the
+ * same, but from a futex perspective the task has to be treated like an exiting
+ * task. This is especially important for the sanity check for private futexes
+ * in attach_to_pi_owner() which compares the owner's mm with the waiter's mm.
+ *
+ * That check would give the wrong answer if futex_cleanup_end() would
+ * set the state to FUTEX_STATE_OK as long as the task still has the old
+ * mm.
+ *
+ * After the task has switched to the new mm it sets it to
+ * FUTEX_STATE_OK again in futex_exec_done().
+ */
+void futex_exit_exec_release(struct task_struct *tsk)
 {
 	futex_cleanup_begin(tsk);
 	futex_cleanup(tsk);
 	futex_cleanup_end(tsk);
 }
 
-void futex_exec_release(struct task_struct *tsk)
-{
-	/*
-	 * exec() makes it interesting for futexes because the TID of the task
-	 * stays the same, but from a futex perspective the task has to be
-	 * treated like an exiting task. This is especially important for the
-	 * sanity check for private futexes in attach_to_pi_owner() which
-	 * compares the owner's mm with the waiter's mm.
-	 *
-	 * That check would give the wrong answer if futex_cleanup_end() would
-	 * set the state to FUTEX_STATE_OK as long as the task still has the old
-	 * mm.
-	 *
-	 * After the task has switched to the new mm it sets it to
-	 * FUTEX_STATE_OK again in futex_exec_done().
-	 */
-	futex_exit_release(tsk);
-}
-
 /*
  * exec() has switched to the new mm. Futex operations are safe again.
  */