Re: [PATCH] fs: process fput task_work with TWA_SIGNAL

[Jens Axboe <axboe@kernel.dk>]

On 1/7/21 3:17 PM, Doug Anderson wrote:
> Hi,
> 
> On Tue, Jan 5, 2021 at 10:30 AM Jens Axboe <axboe@kernel.dk> wrote:
>>
>> Song reported a boot regression in a kvm image with 5.11-rc, and bisected
>> it down to the below patch. Debugging this issue, turns out that the boot
>> stalled when a task is waiting on a pipe being released. As we no longer
>> run task_work from get_signal() unless it's queued with TWA_SIGNAL, the
>> task goes idle without running the task_work. This prevents ->release()
>> from being called on the pipe, which another boot task is waiting on.
>>
>> Use TWA_SIGNAL for the file fput work to ensure it's run before the task
>> goes idle.
>>
>> Fixes: 98b89b649fce ("signal: kill JOBCTL_TASK_WORK")
>> Reported-by: Song Liu <songliubraving@fb.com>
>> Signed-off-by: Jens Axboe <axboe@kernel.dk>
> 
> I just spend a bit of time bisecting and landed on commit 98b89b649fce
> ("signal: kill JOBCTL_TASK_WORK") causing my failure to bootup
> mainline.  Your patch fixes my problem.  I haven't done any analysis
> of the code--just testing, thus:
> 
> Tested-by: Douglas Anderson <dianders@chromium.org>

Thanks, adding your Tested-by.

-- 
Jens Axboe