Commit 2cc3c4b3 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'io_uring-5.9-2020-08-15' of git://git.kernel.dk/linux-block

Pull io_uring fixes from Jens Axboe:
 "A few differerent things in here.

  Seems like syzbot got some more io_uring bits wired up, and we got a
  handful of reports and the associated fixes are in here.

  General fixes too, and a lot of them marked for stable.

  Lastly, a bit of fallout from the async buffered reads, where we now
  more easily trigger short reads. Some applications don't really like
  that, so the io_read() code now handles short reads internally, and
  got a cleanup along the way so that it's now easier to read (and
  documented). We're now passing tests that failed before"

* tag 'io_uring-5.9-2020-08-15' of git://git.kernel.dk/linux-block:
  io_uring: short circuit -EAGAIN for blocking read attempt
  io_uring: sanitize double poll handling
  io_uring: internally retry short reads
  io_uring: retain iov_iter state over io_read/io_write calls
  task_work: only grab task signal lock when needed
  io_uring: enable lookup of links holding inflight files
  io_uring: fail poll arm on queue proc failure
  io_uring: hold 'ctx' reference around task_work queue + execute
  fs: RWF_NOWAIT should imply IOCB_NOIO
  io_uring: defer file table grabbing request cleanup for locked requests
  io_uring: add missing REQ_F_COMP_LOCKED for nested requests
  io_uring: fix recursive completion locking on oveflow flush
  io_uring: use TWA_SIGNAL for task_work uncondtionally
  io_uring: account locked memory before potential error case
  io_uring: set ctx sq/cq entry count earlier
  io_uring: Fix NULL pointer dereference in loop_rw_iter()
  io_uring: add comments on how the async buffered read retry works
  io_uring: io_async_buf_func() need not test page bit
parents 6f6aea7e f91daf56
This diff is collapsed.
......@@ -3322,7 +3322,7 @@ static inline int kiocb_set_rw_flags(struct kiocb *ki, rwf_t flags)
if (flags & RWF_NOWAIT) {
if (!(ki->ki_filp->f_mode & FMODE_NOWAIT))
return -EOPNOTSUPP;
kiocb_flags |= IOCB_NOWAIT;
kiocb_flags |= IOCB_NOWAIT | IOCB_NOIO;
}
if (flags & RWF_HIPRI)
kiocb_flags |= IOCB_HIPRI;
......
......@@ -2541,7 +2541,21 @@ bool get_signal(struct ksignal *ksig)
relock:
spin_lock_irq(&sighand->siglock);
current->jobctl &= ~JOBCTL_TASK_WORK;
/*
* Make sure we can safely read ->jobctl() in task_work add. As Oleg
* states:
*
* It pairs with mb (implied by cmpxchg) before READ_ONCE. So we
* roughly have
*
* task_work_add: get_signal:
* STORE(task->task_works, new_work); STORE(task->jobctl);
* mb(); mb();
* LOAD(task->jobctl); LOAD(task->task_works);
*
* and we can rely on STORE-MB-LOAD [ in task_work_add].
*/
smp_store_mb(current->jobctl, current->jobctl & ~JOBCTL_TASK_WORK);
if (unlikely(current->task_works)) {
spin_unlock_irq(&sighand->siglock);
task_work_run();
......
......@@ -42,7 +42,13 @@ task_work_add(struct task_struct *task, struct callback_head *work, int notify)
set_notify_resume(task);
break;
case TWA_SIGNAL:
if (lock_task_sighand(task, &flags)) {
/*
* Only grab the sighand lock if we don't already have some
* task_work pending. This pairs with the smp_store_mb()
* in get_signal(), see comment there.
*/
if (!(READ_ONCE(task->jobctl) & JOBCTL_TASK_WORK) &&
lock_task_sighand(task, &flags)) {
task->jobctl |= JOBCTL_TASK_WORK;
signal_wake_up(task, 0);
unlock_task_sighand(task, &flags);
......
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