exit/exec: Seperate mm_release()

commit 4610ba7ad877fafc0a25a30c6c82015304120426 upstream

mm_release() contains the futex exit handling. mm_release() is called from
do_exit()->exit_mm() and from exec()->exec_mm().

In the exit_mm() case PF_EXITING and the futex state is updated. In the
exec_mm() case these states are not touched.

As the futex exit code needs further protections against exit races, this
needs to be split into two functions.

Preparatory only, no functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20191106224556.240518241@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/exec.c b/fs/exec.c
index 52788644c4af23488f34ca1852165db1f9dee43c..6eea921a7e72f1578eeafd902a5f4de17f0f5abd 100644 (file)
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1011,7 +1011,7 @@ static int exec_mmap(struct mm_struct *mm)
        /* Notify parent that we're no longer interested in the old VM */
        tsk = current;
        old_mm = current->mm;
-       mm_release(tsk, old_mm);
+       exec_mm_release(tsk, old_mm);
 
        if (old_mm) {
                sync_mm_rss(old_mm);

diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h
index 766bbe8138615663c48c45a8e7f7602a3133c98e..8d3b7e731b74291d919eae1297ddf365f43e1063 100644 (file)
--- a/include/linux/sched/mm.h
+++ b/include/linux/sched/mm.h
@@ -119,8 +119,10 @@ 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 */
-extern void mm_release(struct task_struct *, struct mm_struct *);
+/* 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 *);
 
 #ifdef CONFIG_MEMCG
 extern void mm_update_next_owner(struct mm_struct *mm);

diff --git a/kernel/exit.c b/kernel/exit.c
index bda17a76e94f0e0e0dbea83b429b39aef8dad3c3..38de88f8f75daea7bdff12caa81ff6d1eecde87f 100644 (file)
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -498,7 +498,7 @@ static void exit_mm(void)
        struct mm_struct *mm = current->mm;
        struct core_state *core_state;
 
-       mm_release(current, mm);
+       exit_mm_release(current, mm);
        if (!mm)
                return;
        sync_mm_rss(mm);

diff --git a/kernel/fork.c b/kernel/fork.c
index ee83f4ee5616606cb4499e8f5776eb216846ea74..1982db8bebb3cda6c2be6ade57e5acb2f3918f71 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1217,7 +1217,7 @@ static int wait_for_vfork_done(struct task_struct *child,
  * restoring the old one. . .
  * Eric Biederman 10 January 1998
  */
-void mm_release(struct task_struct *tsk, struct mm_struct *mm)
+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);
@@ -1254,6 +1254,16 @@ 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)
+{
+       mm_release(tsk, mm);
+}
+
+void exec_mm_release(struct task_struct *tsk, struct mm_struct *mm)
+{
+       mm_release(tsk, mm);
+}
+
 /*
  * Allocate a new mm structure and copy contents from the
  * mm structure of the passed in task structure.