diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2016-09-15 22:45:44 -0700 |
|---|---|---|
| committer | Amit Pundir <amit.pundir@linaro.org> | 2017-08-11 19:31:04 +0530 |
| commit | 78605f254eb7dbda807b254714c3344e7c8fcb41 (patch) | |
| tree | 753aea9f0db771e05e49c3baca5729aa789afdb9 | |
| parent | c43b8d7ce783f486bdfcbaed2bc5bcdb8c6c8c17 (diff) | |
UPSTREAM: kthread: Pin the stack via try_get_task_stack()/put_task_stack() in to_live_kthread() function
get_task_struct(tsk) no longer pins tsk->stack so all users of
to_live_kthread() should do try_get_task_stack/put_task_stack to protect
"struct kthread" which lives on kthread's stack.
TODO: Kill to_live_kthread(), perhaps we can even kill "struct kthread" too,
and rework kthread_stop(), it can use task_work_add() to sync with the exiting
kernel thread.
Message-Id: <20160629180357.GA7178@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jann Horn <jann@thejh.net>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/cb9b16bbc19d4aea4507ab0552e4644c1211d130.1474003868.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Bug: 38331309
Change-Id: I2872658e56dcb1ab4173c490ef8f52affa54a404
(cherry picked from commit 23196f2e5f5d810578a772785807dcdc2b9fdce9)
Signed-off-by: Zubin Mithra <zsm@google.com>
| -rw-r--r-- | kernel/kthread.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/kernel/kthread.c b/kernel/kthread.c index 698b8dec3074..d9b0be5c6a5f 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -65,7 +65,7 @@ static inline struct kthread *to_kthread(struct task_struct *k) static struct kthread *to_live_kthread(struct task_struct *k) { struct completion *vfork = ACCESS_ONCE(k->vfork_done); - if (likely(vfork)) + if (likely(vfork) && try_get_task_stack(k)) return __to_kthread(vfork); return NULL; } @@ -427,8 +427,10 @@ void kthread_unpark(struct task_struct *k) { struct kthread *kthread = to_live_kthread(k); - if (kthread) + if (kthread) { __kthread_unpark(k, kthread); + put_task_stack(k); + } } EXPORT_SYMBOL_GPL(kthread_unpark); @@ -457,6 +459,7 @@ int kthread_park(struct task_struct *k) wait_for_completion(&kthread->parked); } } + put_task_stack(k); ret = 0; } return ret; @@ -492,6 +495,7 @@ int kthread_stop(struct task_struct *k) __kthread_unpark(k, kthread); wake_up_process(k); wait_for_completion(&kthread->exited); + put_task_stack(k); } ret = k->exit_code; put_task_struct(k); |