From: "孙世龙 sunshilong" <sunshilong369@gmail.com>
To: "Valdis Klētnieks" <valdis.kletnieks@vt.edu>
Cc: kernelnewbies <Kernelnewbies@kernelnewbies.org>
Subject: Re: How can I investigate the cause of "watchdog: BUG: soft lockup"?
Date: Wed, 8 Jul 2020 13:19:35 +0800 [thread overview]
Message-ID: <CAAvDm6Y-69S2=4mp=TwkbgXjKsy8WgwfK62+3ze5baSVuNnN_g@mail.gmail.com> (raw)
In-Reply-To: <CAAvDm6aemz5qoYUNtyaGc0EhtfgheQGKYnDpWeRg1G6M2Sca_w@mail.gmail.com>
Hi,
Thank you for your help and patience.
>Jul 3 10:23:31 yx kernel: [ 1176.166204] CPU: 0 PID: 1837 Comm:
>rt_cansend Tainted: G OE 4.19.84-solve-alc-failure #1
>Jul 3 10:23:31 yx kernel: [ 1176.166209] I-pipe domain: Linux
>Jul 3 10:23:31 yx kernel: [ 1176.166218] RIP:
>0010:queued_spin_lock_slowpath+0xd9/0x1a0
...
> Jul 3 10:23:31 yx kernel: [ 1176.166252] Call Trace:
> Jul 3 10:23:31 yx kernel: [ 1176.166261] _raw_spin_lock+0x20/0x30
> Jul 3 10:23:31 yx kernel: [ 1176.166270] can_write+0x6c/0x2c0 [advcan]
> Jul 3 10:23:31 yx kernel: [ 1176.166292] __vfs_write+0x3a/0x190
One more question, what's the relation between "queued_spin_lock_slowpath"
and "_raw_spin_lock"?
Best Regards.
孙世龙 sunshilong <sunshilong369@gmail.com> 于2020年7月4日周六 下午5:13写道:
>
> Hi, Valdis Klētnieks
>
> Thank you for taking the time to respond to me.
> I have a better understanding of this matter.
>
> >> Can I draw the conclusion that continually acquiring the spinlock causes the soft
> >> lockup and the CPU has been stuck for 22s?
> >> Can I think in this way?
>
> >No. It's been stuck for 22s *TRYING* and *FAILING* to get the spinlock.
>
> I see. So there is a thread that has held the corresponding spinlock
> for more 22s, and a CPU is sticking(busy acquiring the spinlock) at the
> same duration.
> Can I think in this way?
>
> Thank you for your attention to this matter.
> Best Regards.
>
> Valdis Klētnieks <valdis.kletnieks@vt.edu> 于2020年7月4日周六 下午4:09写道:
>
> 孙世龙 sunshilong <sunshilong369@gmail.com> 于2020年7月4日周六 下午5:04写道:
> >
> > Hi, Valdis Klētnieks
> >
> > Thank you for taking the time to respond to me.
> > I have a better understanding of this matter.
> >
> > >> Can I draw the conclusion that continually acquiring the spinlock causes the soft
> > >> lockup and the CPU has been stuck for 22s?
> > >> Can I think in this way?
> >
> > >No. It's been stuck for 22s *TRYING* and *FAILING* to get the spinlock.
> >
> > I see. So there is a thread that has held the corresponding spinlock
> > for more 22s.
> > Can I think in this way?
> >
> > Thank you for your attention to this matter.
> > Best Regards.
> >
> > Valdis Klētnieks <valdis.kletnieks@vt.edu> 于2020年7月4日周六 下午4:09写道:
> > >
> > >
> > > > Can I draw the conclusion that continually acquiring the spinlock causes the soft
> > > > lockup and the CPU has been stuck for 22s?
> > > > Can I think in this way?
> > >
> > > No. It's been stuck for 22s *TRYING* and *FAILING* to get the spinlock.
> > >
> > > For comparison - spinlocks are usually used when you need a lock, but the
> > > code protected by the lock is short (things like adding to a linked list, etc),
> > > so it should again become available in milliseconds - things where it would take
> > > longer to put this thread to sleep and wake another one up than we expect
> > > to be waiting for this lock.
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prev parent reply other threads:[~2020-07-08 5:20 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-04 2:20 How can I investigate the cause of "watchdog: BUG: soft lockup"? 孙世龙 sunshilong
2020-07-04 4:39 ` Valdis Klētnieks
2020-07-04 7:51 ` 孙世龙 sunshilong
2020-07-04 8:09 ` Valdis Klētnieks
2020-07-04 9:04 ` 孙世龙 sunshilong
2020-07-04 9:13 ` 孙世龙 sunshilong
2020-07-08 5:19 ` 孙世龙 sunshilong [this message]
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