linux-kernel - Re: [PATCH v3 6/6] freezer,sched: Rewrite core freezer logic

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <8b0e1945-d4ef-2aef-fb5d-1b6b8397b169@linux.ibm.com>
Date:   Mon, 26 Sep 2022 15:54:10 +0200
From:   Christian Borntraeger <borntraeger@...ux.ibm.com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     bigeasy@...utronix.de, dietmar.eggemann@....com,
        ebiederm@...ssion.com, linux-kernel@...r.kernel.org,
        linux-pm@...r.kernel.org, mgorman@...e.de, mingo@...nel.org,
        oleg@...hat.com, rjw@...ysocki.net, rostedt@...dmis.org,
        tj@...nel.org, vincent.guittot@...aro.org, will@...nel.org,
        Marc Hartmayer <mhartmay@...ux.ibm.com>,
        Amit Shah <amit@...nel.org>,
        "virtualization@...ts.linux-foundation.org" 
        <virtualization@...ts.linux-foundation.org>
Subject: Re: [PATCH v3 6/6] freezer,sched: Rewrite core freezer logic



Am 26.09.22 um 15:37 schrieb Peter Zijlstra:
> On Mon, Sep 26, 2022 at 03:23:10PM +0200, Christian Borntraeger wrote:
>> Am 26.09.22 um 14:55 schrieb Peter Zijlstra:
>>
>>> Could you please test with something like the below on? I can boot that
>>> with KVM, but obviously I didn't suffer any weirdness to begin with :/
>>>
>>> ---
>>> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
>>> index 4e6a6417211f..ef9ccfc3a8c0 100644
>>> --- a/kernel/sched/core.c
>>> +++ b/kernel/sched/core.c
>>> @@ -4051,6 +4051,8 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
>>>    	unsigned long flags;
>>>    	int cpu, success = 0;
>>> +	WARN_ON_ONCE(state & TASK_FREEZABLE);
>>> +
>>>    	preempt_disable();
>>>    	if (p == current) {
>>>    		/*
>>
>> Does not seem to trigger.
> 
> Moo -- quite the puzzle this :/ I'll go stare at it more then.

In the end this is about the end of the sshd process (shutting it down).
I can also trigger the problem by sending a SIGTERM so its not about
the shutdown itself.
Pofiling the guest I see scheduler functions like sched_clock, pick_next_entity,
update_min_vruntime and so on with 100% system time.