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To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Alexander Viro <viro@zeniv.linux.org.uk>
From:   Jens Axboe <axboe@kernel.dk>
Subject: [GIT PULL] task_work fix for 5.11
Message-ID: <87a18f00-8f32-edcc-4595-da70e623febc@kernel.dk>
Date:   Tue, 19 Jan 2021 11:15:54 -0700
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Hi Linus,

The TIF_NOTIFY_SIGNAL change inadvertently removed the unconditional
task_work run we had in get_signal(). This caused a regression for some
setups, since we're relying on eg ____fput() being run to close and
release, for example, a pipe and wake the other end. For 5.11, I prefer
the simple solution of just reinstating the unconditional run, even if
it conceptually doesn't make much sense - if you need that kind of
guarantee, you should be using TWA_SIGNAL instead of TWA_NOTIFY. But
it's the trivial fix for 5.11, and would ensure that other potential
gotchas/assumptions for task_work don't regress for 5.11.

we're looking into further simplifying the task_work notifications for
5.12 which would resolve that too.

Please pull!


The following changes since commit e71ba9452f0b5b2e8dc8aa5445198cd9214a6a62:

  Linux 5.11-rc2 (2021-01-03 15:55:30 -0800)

are available in the Git repository at:

  git://git.kernel.dk/linux-block.git tags/task_work-2021-01-19

for you to fetch changes up to 35d0b389f3b23439ad15b610d6e43fc72fc75779:

  task_work: unconditionally run task_work from get_signal() (2021-01-08 09:14:21 -0700)

----------------------------------------------------------------
task_work-2021-01-19

----------------------------------------------------------------
Jens Axboe (1):
      task_work: unconditionally run task_work from get_signal()

 kernel/signal.c | 3 +++
 1 file changed, 3 insertions(+)

-- 
Jens Axboe