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To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        io-uring <io-uring@vger.kernel.org>
From:   Jens Axboe <axboe@kernel.dk>
Subject: [GIT PULL] io_uring fixes for 5.8-rc4
Message-ID: <ac36babd-3eb7-8f91-7ba1-e722def24b67@kernel.dk>
Date:   Wed, 1 Jul 2020 22:30:24 -0600
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Hi Linus,

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. 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.

Please pull!

The following changes since commit d60b5fbc1ce8210759b568da49d149b868e7c6d3:

  io_uring: fix current->mm NULL dereference on exit (2020-06-25 07:20:43 -0600)

are available in the Git repository at:

  git://git.kernel.dk/linux-block.git tags/io_uring-5.8-2020-07-01

for you to fetch changes up to ce593a6c480a22acba08795be313c0c6d49dd35d:

  io_uring: use signal based task_work running (2020-06-30 12:39:05 -0600)

----------------------------------------------------------------
io_uring-5.8-2020-07-01

----------------------------------------------------------------
Jens Axboe (1):
      io_uring: use signal based task_work running

Oleg Nesterov (1):
      task_work: teach task_work_add() to do signal_wake_up()

 fs/io_uring.c                | 32 ++++++++++++++++++++++++--------
 include/linux/sched/jobctl.h |  4 +++-
 include/linux/task_work.h    |  5 ++++-
 kernel/signal.c              | 10 +++++++---
 kernel/task_work.c           | 16 ++++++++++++++--
 5 files changed, 52 insertions(+), 15 deletions(-)

-- 
Jens Axboe