linux-kernel - [PATCH 4.9 08/32] futex: Split futex_mm

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Date:   Tue,  2 Feb 2021 14:38:31 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...nel.org>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Lee Jones <lee.jones@...aro.org>
Subject: [PATCH 4.9 08/32] futex: Split futex_mm_release() for exit/exec

From: Thomas Gleixner <tglx@...utronix.de>

commit 150d71584b12809144b8145b817e83b81158ae5f upstream.

To allow separate handling of the futex exit state in the futex exit code
for exit and exec, split futex_mm_release() into two functions and invoke
them from the corresponding exit/exec_mm_release() callsites.

Preparatory only, no functional change.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Reviewed-by: Ingo Molnar <mingo@...nel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Link: https://lkml.kernel.org/r/20191106224556.332094221@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Signed-off-by: Lee Jones <lee.jones@...aro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 include/linux/futex.h |    6 ++++--
 kernel/fork.c         |    5 ++---
 kernel/futex.c        |    7 ++++++-
 3 files changed, 12 insertions(+), 6 deletions(-)

--- a/include/linux/futex.h
+++ b/include/linux/futex.h
@@ -98,13 +98,15 @@ static inline void futex_exit_done(struc
 	tsk->futex_state = FUTEX_STATE_DEAD;
 }
 
-void futex_mm_release(struct task_struct *tsk);
+void futex_exit_release(struct task_struct *tsk);
+void futex_exec_release(struct task_struct *tsk);
 
 long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
 	      u32 __user *uaddr2, u32 val2, u32 val3);
 #else
 static inline void futex_init_task(struct task_struct *tsk) { }
-static inline void futex_mm_release(struct task_struct *tsk) { }
 static inline void futex_exit_done(struct task_struct *tsk) { }
+static inline void futex_exit_release(struct task_struct *tsk) { }
+static inline void futex_exec_release(struct task_struct *tsk) { }
 #endif
 #endif
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1084,9 +1084,6 @@ static int wait_for_vfork_done(struct ta
  */
 static void mm_release(struct task_struct *tsk, struct mm_struct *mm)
 {
-	/* Get rid of any futexes when releasing the mm */
-	futex_mm_release(tsk);
-
 	uprobe_free_utask(tsk);
 
 	/* Get rid of any cached register state */
@@ -1121,11 +1118,13 @@ static void mm_release(struct task_struc
 
 void exit_mm_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);
 	mm_release(tsk, mm);
 }
 
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -3269,7 +3269,7 @@ static void exit_robust_list(struct task
 				   curr, pip);
 }
 
-void futex_mm_release(struct task_struct *tsk)
+void futex_exec_release(struct task_struct *tsk)
 {
 	if (unlikely(tsk->robust_list)) {
 		exit_robust_list(tsk);
@@ -3287,6 +3287,11 @@ void futex_mm_release(struct task_struct
 		exit_pi_state_list(tsk);
 }
 
+void futex_exit_release(struct task_struct *tsk)
+{
+	futex_exec_release(tsk);
+}
+
 long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
 		u32 __user *uaddr2, u32 val2, u32 val3)
 {