From: Thomas Gleixner tglx@linutronix.de
stable inclusion from linux-4.19.172 commit 9425476fb17a29b9f1c564321ae4b80129534c57
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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: Yang Yingliang yangyingliang@huawei.com Signed-off-by: Cheng Jian cj.chengjian@huawei.com --- fs/exec.c | 2 +- include/linux/sched/mm.h | 6 ++++-- kernel/exit.c | 2 +- kernel/fork.c | 12 +++++++++++- 4 files changed, 17 insertions(+), 5 deletions(-)
diff --git a/fs/exec.c b/fs/exec.c index 8099ac98e605..07b536eb6c44 100644 --- 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 290a613687b5..deb1bf7f5aa7 100644 --- 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 e8a3ca3a3685..1abc9b4a626d 100644 --- 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 82345524b086..a647bf7ee65b 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1275,7 +1275,7 @@ 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); @@ -1312,6 +1312,16 @@ 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.