From: Joe Lawrence <joe.lawrence@redhat.com>
To: Miroslav Benes <mbenes@suse.cz>, Dong Kai <dongkai11@huawei.com>
Cc: jpoimboe@redhat.com, jikos@kernel.org, pmladek@suse.com,
axboe@kernel.dk, live-patching@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] livepatch: klp_send_signal should treat PF_IO_WORKER like PF_KTHREAD
Date: Thu, 25 Mar 2021 12:43:06 -0400 [thread overview]
Message-ID: <01cbab2f-da8b-f289-2241-d258406a4b6c@redhat.com> (raw)
In-Reply-To: <alpine.LSU.2.21.2103251023320.30447@pobox.suse.cz>
On 3/25/21 5:26 AM, Miroslav Benes wrote:
> On Thu, 25 Mar 2021, Dong Kai wrote:
>
>> commit 15b2219facad ("kernel: freezer should treat PF_IO_WORKER like
>> PF_KTHREAD for freezing") is to fix the freezeing issue of IO threads
>> by making the freezer not send them fake signals.
>>
>> Here live patching consistency model call klp_send_signals to wake up
>> all tasks by send fake signal to all non-kthread which only check the
>> PF_KTHREAD flag, so it still send signal to io threads which may lead to
>> freezeing issue of io threads.
>
> I suppose this could happen, but it will also affect the live patching
> transition if the io threads do not react to signals.
>
> Are you able to reproduce it easily? I mean, is there a testcase I could
> use to take a closer look?
>
If repro is only hypothetical at this point, perhaps we can artificially
create it in selftests? And useful to verify the future change you
mentioned in your other reply?
-- Joe
next prev parent reply other threads:[~2021-03-25 16:44 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-25 1:48 Dong Kai
2021-03-25 2:51 ` Joe Lawrence
2021-03-25 9:30 ` Miroslav Benes
2021-03-25 16:30 ` Jens Axboe
2021-03-26 8:39 ` Miroslav Benes
2021-03-25 9:26 ` Miroslav Benes
2021-03-25 16:43 ` Joe Lawrence [this message]
2021-03-26 6:31 ` dongkai (H)
2021-03-25 16:29 ` Jens Axboe
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