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>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/exec.c b/fs/exec.c
index cd5da140f94cb48e6ee457c5b32a435c86194426..319a1f5732fa95d18af7b47a5f163ffa389601c0 100644 (file)
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1021,7 +1021,7 @@ 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.h b/include/linux/sched.h
index 4de48b251447fa8542c85604804cc99eb09bef46..fcbe5904cbd977674a1949f3f0cdbfd9160ffe74 100644 (file)
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2955,8 +2955,10 @@ 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_HAVE_COPY_THREAD_TLS
 extern int copy_thread_tls(unsigned long, unsigned long, unsigned long,

diff --git a/kernel/exit.c b/kernel/exit.c
index 969e1468f253815652f824bb050c3e297c60c882..b65285f5ee0c98f07ca84afae860e0d15319e8c6 100644 (file)
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -464,7 +464,7 @@ static void exit_mm(struct task_struct *tsk)
        struct mm_struct *mm = tsk->mm;
        struct core_state *core_state;
 
-       mm_release(tsk, mm);
+       exit_mm_release(tsk, mm);
        if (!mm)
                return;
        sync_mm_rss(mm);

diff --git a/kernel/fork.c b/kernel/fork.c
index 000447bfcfde584e9228fb4e5239ff6c091f4d21..ad9dbbf03d7bc91fc5abd649a110e5b4f681fce3 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1082,7 +1082,7 @@ 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);
@@ -1119,6 +1119,16 @@ 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.