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Merge tag 'io_uring-5.8-2020-07-01' of git://git.kernel.dk/linux-block

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Pull io_uring fixes from Jens Axboe:
 "One fix in here, for a regression in 5.7 where a task is waiting in
  the kernel for a condition, but that condition won't become true until
  task_work is run. And the task_work can't be run exactly because the
  task is waiting in the kernel, so we'll never make any progress.

  One example of that is registering an eventfd and queueing io_uring
  work, and then the task goes and waits in eventfd read with the
  expectation that it'll get woken (and read an event) when the io_uring
  request completes. The io_uring request is finished through task_work,
  which won't get run while the task is looping in eventfd read"

* tag 'io_uring-5.8-2020-07-01' of git://git.kernel.dk/linux-block:
  io_uring: use signal based task_work running
  task_work: teach task_work_add() to do signal_wake_up()
This commit is contained in:
Linus Torvalds
2020-07-02 14:56:22 -07:00
parent cd77006e01 ce593a6c48
commit c93493b7cd
5 changed files with 52 additions and 15 deletions
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4
include/linux/sched/jobctl.h
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@@ -19,6 +19,7 @@ struct task_struct;
#define JOBCTL_TRAPPING_BIT 21 /* switching to TRACED */
#define JOBCTL_LISTENING_BIT 22 /* ptracer is listening for events */
#define JOBCTL_TRAP_FREEZE_BIT 23 /* trap for cgroup freezer */
#define JOBCTL_TASK_WORK_BIT 24 /* set by TWA_SIGNAL */
#define JOBCTL_STOP_DEQUEUED (1UL << JOBCTL_STOP_DEQUEUED_BIT)
#define JOBCTL_STOP_PENDING (1UL << JOBCTL_STOP_PENDING_BIT)
@@ -28,9 +29,10 @@ struct task_struct;
#define JOBCTL_TRAPPING (1UL << JOBCTL_TRAPPING_BIT)
#define JOBCTL_LISTENING (1UL << JOBCTL_LISTENING_BIT)
#define JOBCTL_TRAP_FREEZE (1UL << JOBCTL_TRAP_FREEZE_BIT)
#define JOBCTL_TASK_WORK (1UL << JOBCTL_TASK_WORK_BIT)
#define JOBCTL_TRAP_MASK (JOBCTL_TRAP_STOP | JOBCTL_TRAP_NOTIFY)
#define JOBCTL_PENDING_MASK (JOBCTL_STOP_PENDING | JOBCTL_TRAP_MASK)
#define JOBCTL_PENDING_MASK (JOBCTL_STOP_PENDING | JOBCTL_TRAP_MASK | JOBCTL_TASK_WORK)
extern bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask);
extern void task_clear_jobctl_trapping(struct task_struct *task);

5
include/linux/task_work.h
View File

@@ -13,7 +13,10 @@ init_task_work(struct callback_head *twork, task_work_func_t func)
twork->func = func;
}
int task_work_add(struct task_struct *task, struct callback_head *twork, bool);
#define TWA_RESUME 1
#define TWA_SIGNAL 2
int task_work_add(struct task_struct *task, struct callback_head *twork, int);
struct callback_head *task_work_cancel(struct task_struct *, task_work_func_t);
void task_work_run(void);