Revision ec057595cb3fb339e692898bedccd566160ba086 authored by Linus Torvalds on 06 December 2019, 20:40:35 UTC, committed by Linus Torvalds on 06 December 2019, 20:40:35 UTC
Similarly to commit 8f868d68d335 ("pipe: Fix missing mask update after pipe_wait()") this fixes a case where the pipe rewrite ended up caching the pipe state incorrectly over a pipe lock drop event. It wasn't quite as obvious, because you needed to splice data from a pipe to a file, which is a fairly unusual operation, but it's completely wrong. Make sure we load the pipe head/tail/size information only after we've waited for there to be data in the pipe. While in that file, also make one of the splice helper functions use the canonical arghument order for pipe_empty(). That's syntactic - pipe emptiness is just that head and tail are equal, and thus mixing up head and tail doesn't really matter. It's still wrong, though. Reported-by: David Sterba <dsterba@suse.cz> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 7ada90e
workqueue_internal.h
/* SPDX-License-Identifier: GPL-2.0 */
/*
* kernel/workqueue_internal.h
*
* Workqueue internal header file. Only to be included by workqueue and
* core kernel subsystems.
*/
#ifndef _KERNEL_WORKQUEUE_INTERNAL_H
#define _KERNEL_WORKQUEUE_INTERNAL_H
#include <linux/workqueue.h>
#include <linux/kthread.h>
#include <linux/preempt.h>
struct worker_pool;
/*
* The poor guys doing the actual heavy lifting. All on-duty workers are
* either serving the manager role, on idle list or on busy hash. For
* details on the locking annotation (L, I, X...), refer to workqueue.c.
*
* Only to be used in workqueue and async.
*/
struct worker {
/* on idle list while idle, on busy hash table while busy */
union {
struct list_head entry; /* L: while idle */
struct hlist_node hentry; /* L: while busy */
};
struct work_struct *current_work; /* L: work being processed */
work_func_t current_func; /* L: current_work's fn */
struct pool_workqueue *current_pwq; /* L: current_work's pwq */
struct list_head scheduled; /* L: scheduled works */
/* 64 bytes boundary on 64bit, 32 on 32bit */
struct task_struct *task; /* I: worker task */
struct worker_pool *pool; /* A: the associated pool */
/* L: for rescuers */
struct list_head node; /* A: anchored at pool->workers */
/* A: runs through worker->node */
unsigned long last_active; /* L: last active timestamp */
unsigned int flags; /* X: flags */
int id; /* I: worker id */
int sleeping; /* None */
/*
* Opaque string set with work_set_desc(). Printed out with task
* dump for debugging - WARN, BUG, panic or sysrq.
*/
char desc[WORKER_DESC_LEN];
/* used only by rescuers to point to the target workqueue */
struct workqueue_struct *rescue_wq; /* I: the workqueue to rescue */
/* used by the scheduler to determine a worker's last known identity */
work_func_t last_func;
};
/**
* current_wq_worker - return struct worker if %current is a workqueue worker
*/
static inline struct worker *current_wq_worker(void)
{
if (in_task() && (current->flags & PF_WQ_WORKER))
return kthread_data(current);
return NULL;
}
/*
* Scheduler hooks for concurrency managed workqueue. Only to be used from
* sched/ and workqueue.c.
*/
void wq_worker_running(struct task_struct *task);
void wq_worker_sleeping(struct task_struct *task);
work_func_t wq_worker_last_func(struct task_struct *task);
#endif /* _KERNEL_WORKQUEUE_INTERNAL_H */
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