mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 01:10:04 +00:00
![Peter Zijlstra](/assets/img/avatar_default.png)
Gaurav reports that commit:85f1abe001
("kthread, sched/wait: Fix kthread_parkme() completion issue") isn't working for him. Because of the following race: > controller Thread CPUHP Thread > takedown_cpu > kthread_park > kthread_parkme > Set KTHREAD_SHOULD_PARK > smpboot_thread_fn > set Task interruptible > > > wake_up_process > if (!(p->state & state)) > goto out; > > Kthread_parkme > SET TASK_PARKED > schedule > raw_spin_lock(&rq->lock) > ttwu_remote > waiting for __task_rq_lock > context_switch > > finish_lock_switch > > > > Case TASK_PARKED > kthread_park_complete > > > SET Running Furthermore, Oleg noticed that the whole scheduler TASK_PARKED handling is buggered because the TASK_DEAD thing is done with preemption disabled, the current code can still complete early on preemption :/ So basically revert that earlier fix and go with a variant of the alternative mentioned in the commit. Promote TASK_PARKED to special state to avoid the store-store issue on task->state leading to the WARN in kthread_unpark() -> __kthread_bind(). But in addition, add wait_task_inactive() to kthread_park() to ensure the task really is PARKED when we return from kthread_park(). This avoids the whole kthread still gets migrated nonsense -- although it would be really good to get this done differently. Reported-by: Gaurav Kohli <gkohli@codeaurora.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes:85f1abe001
("kthread, sched/wait: Fix kthread_parkme() completion issue") Signed-off-by: Ingo Molnar <mingo@kernel.org>
211 lines
6.5 KiB
C
211 lines
6.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef _LINUX_KTHREAD_H
|
|
#define _LINUX_KTHREAD_H
|
|
/* Simple interface for creating and stopping kernel threads without mess. */
|
|
#include <linux/err.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/cgroup.h>
|
|
|
|
__printf(4, 5)
|
|
struct task_struct *kthread_create_on_node(int (*threadfn)(void *data),
|
|
void *data,
|
|
int node,
|
|
const char namefmt[], ...);
|
|
|
|
/**
|
|
* kthread_create - create a kthread on the current node
|
|
* @threadfn: the function to run in the thread
|
|
* @data: data pointer for @threadfn()
|
|
* @namefmt: printf-style format string for the thread name
|
|
* @arg...: arguments for @namefmt.
|
|
*
|
|
* This macro will create a kthread on the current node, leaving it in
|
|
* the stopped state. This is just a helper for kthread_create_on_node();
|
|
* see the documentation there for more details.
|
|
*/
|
|
#define kthread_create(threadfn, data, namefmt, arg...) \
|
|
kthread_create_on_node(threadfn, data, NUMA_NO_NODE, namefmt, ##arg)
|
|
|
|
|
|
struct task_struct *kthread_create_on_cpu(int (*threadfn)(void *data),
|
|
void *data,
|
|
unsigned int cpu,
|
|
const char *namefmt);
|
|
|
|
/**
|
|
* kthread_run - create and wake a thread.
|
|
* @threadfn: the function to run until signal_pending(current).
|
|
* @data: data ptr for @threadfn.
|
|
* @namefmt: printf-style name for the thread.
|
|
*
|
|
* Description: Convenient wrapper for kthread_create() followed by
|
|
* wake_up_process(). Returns the kthread or ERR_PTR(-ENOMEM).
|
|
*/
|
|
#define kthread_run(threadfn, data, namefmt, ...) \
|
|
({ \
|
|
struct task_struct *__k \
|
|
= kthread_create(threadfn, data, namefmt, ## __VA_ARGS__); \
|
|
if (!IS_ERR(__k)) \
|
|
wake_up_process(__k); \
|
|
__k; \
|
|
})
|
|
|
|
void free_kthread_struct(struct task_struct *k);
|
|
void kthread_bind(struct task_struct *k, unsigned int cpu);
|
|
void kthread_bind_mask(struct task_struct *k, const struct cpumask *mask);
|
|
int kthread_stop(struct task_struct *k);
|
|
bool kthread_should_stop(void);
|
|
bool kthread_should_park(void);
|
|
bool kthread_freezable_should_stop(bool *was_frozen);
|
|
void *kthread_data(struct task_struct *k);
|
|
void *kthread_probe_data(struct task_struct *k);
|
|
int kthread_park(struct task_struct *k);
|
|
void kthread_unpark(struct task_struct *k);
|
|
void kthread_parkme(void);
|
|
|
|
int kthreadd(void *unused);
|
|
extern struct task_struct *kthreadd_task;
|
|
extern int tsk_fork_get_node(struct task_struct *tsk);
|
|
|
|
/*
|
|
* Simple work processor based on kthread.
|
|
*
|
|
* This provides easier way to make use of kthreads. A kthread_work
|
|
* can be queued and flushed using queue/kthread_flush_work()
|
|
* respectively. Queued kthread_works are processed by a kthread
|
|
* running kthread_worker_fn().
|
|
*/
|
|
struct kthread_work;
|
|
typedef void (*kthread_work_func_t)(struct kthread_work *work);
|
|
void kthread_delayed_work_timer_fn(struct timer_list *t);
|
|
|
|
enum {
|
|
KTW_FREEZABLE = 1 << 0, /* freeze during suspend */
|
|
};
|
|
|
|
struct kthread_worker {
|
|
unsigned int flags;
|
|
spinlock_t lock;
|
|
struct list_head work_list;
|
|
struct list_head delayed_work_list;
|
|
struct task_struct *task;
|
|
struct kthread_work *current_work;
|
|
};
|
|
|
|
struct kthread_work {
|
|
struct list_head node;
|
|
kthread_work_func_t func;
|
|
struct kthread_worker *worker;
|
|
/* Number of canceling calls that are running at the moment. */
|
|
int canceling;
|
|
};
|
|
|
|
struct kthread_delayed_work {
|
|
struct kthread_work work;
|
|
struct timer_list timer;
|
|
};
|
|
|
|
#define KTHREAD_WORKER_INIT(worker) { \
|
|
.lock = __SPIN_LOCK_UNLOCKED((worker).lock), \
|
|
.work_list = LIST_HEAD_INIT((worker).work_list), \
|
|
.delayed_work_list = LIST_HEAD_INIT((worker).delayed_work_list),\
|
|
}
|
|
|
|
#define KTHREAD_WORK_INIT(work, fn) { \
|
|
.node = LIST_HEAD_INIT((work).node), \
|
|
.func = (fn), \
|
|
}
|
|
|
|
#define KTHREAD_DELAYED_WORK_INIT(dwork, fn) { \
|
|
.work = KTHREAD_WORK_INIT((dwork).work, (fn)), \
|
|
.timer = __TIMER_INITIALIZER(kthread_delayed_work_timer_fn,\
|
|
TIMER_IRQSAFE), \
|
|
}
|
|
|
|
#define DEFINE_KTHREAD_WORKER(worker) \
|
|
struct kthread_worker worker = KTHREAD_WORKER_INIT(worker)
|
|
|
|
#define DEFINE_KTHREAD_WORK(work, fn) \
|
|
struct kthread_work work = KTHREAD_WORK_INIT(work, fn)
|
|
|
|
#define DEFINE_KTHREAD_DELAYED_WORK(dwork, fn) \
|
|
struct kthread_delayed_work dwork = \
|
|
KTHREAD_DELAYED_WORK_INIT(dwork, fn)
|
|
|
|
/*
|
|
* kthread_worker.lock needs its own lockdep class key when defined on
|
|
* stack with lockdep enabled. Use the following macros in such cases.
|
|
*/
|
|
#ifdef CONFIG_LOCKDEP
|
|
# define KTHREAD_WORKER_INIT_ONSTACK(worker) \
|
|
({ kthread_init_worker(&worker); worker; })
|
|
# define DEFINE_KTHREAD_WORKER_ONSTACK(worker) \
|
|
struct kthread_worker worker = KTHREAD_WORKER_INIT_ONSTACK(worker)
|
|
#else
|
|
# define DEFINE_KTHREAD_WORKER_ONSTACK(worker) DEFINE_KTHREAD_WORKER(worker)
|
|
#endif
|
|
|
|
extern void __kthread_init_worker(struct kthread_worker *worker,
|
|
const char *name, struct lock_class_key *key);
|
|
|
|
#define kthread_init_worker(worker) \
|
|
do { \
|
|
static struct lock_class_key __key; \
|
|
__kthread_init_worker((worker), "("#worker")->lock", &__key); \
|
|
} while (0)
|
|
|
|
#define kthread_init_work(work, fn) \
|
|
do { \
|
|
memset((work), 0, sizeof(struct kthread_work)); \
|
|
INIT_LIST_HEAD(&(work)->node); \
|
|
(work)->func = (fn); \
|
|
} while (0)
|
|
|
|
#define kthread_init_delayed_work(dwork, fn) \
|
|
do { \
|
|
kthread_init_work(&(dwork)->work, (fn)); \
|
|
__init_timer(&(dwork)->timer, \
|
|
kthread_delayed_work_timer_fn, \
|
|
TIMER_IRQSAFE); \
|
|
} while (0)
|
|
|
|
int kthread_worker_fn(void *worker_ptr);
|
|
|
|
__printf(2, 3)
|
|
struct kthread_worker *
|
|
kthread_create_worker(unsigned int flags, const char namefmt[], ...);
|
|
|
|
__printf(3, 4) struct kthread_worker *
|
|
kthread_create_worker_on_cpu(int cpu, unsigned int flags,
|
|
const char namefmt[], ...);
|
|
|
|
bool kthread_queue_work(struct kthread_worker *worker,
|
|
struct kthread_work *work);
|
|
|
|
bool kthread_queue_delayed_work(struct kthread_worker *worker,
|
|
struct kthread_delayed_work *dwork,
|
|
unsigned long delay);
|
|
|
|
bool kthread_mod_delayed_work(struct kthread_worker *worker,
|
|
struct kthread_delayed_work *dwork,
|
|
unsigned long delay);
|
|
|
|
void kthread_flush_work(struct kthread_work *work);
|
|
void kthread_flush_worker(struct kthread_worker *worker);
|
|
|
|
bool kthread_cancel_work_sync(struct kthread_work *work);
|
|
bool kthread_cancel_delayed_work_sync(struct kthread_delayed_work *work);
|
|
|
|
void kthread_destroy_worker(struct kthread_worker *worker);
|
|
|
|
#ifdef CONFIG_BLK_CGROUP
|
|
void kthread_associate_blkcg(struct cgroup_subsys_state *css);
|
|
struct cgroup_subsys_state *kthread_blkcg(void);
|
|
#else
|
|
static inline void kthread_associate_blkcg(struct cgroup_subsys_state *css) { }
|
|
static inline struct cgroup_subsys_state *kthread_blkcg(void)
|
|
{
|
|
return NULL;
|
|
}
|
|
#endif
|
|
#endif /* _LINUX_KTHREAD_H */
|