From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: "Levin, Alexander (Sasha Levin)" <alexander.levin@verizon.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Sasha Levin <levinsasha928@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
"linux-kernel@vger.kernel.org List"
<linux-kernel@vger.kernel.org>,
"pmladek@suse.com" <pmladek@suse.com>,
"sergey.senozhatsky@gmail.com" <sergey.senozhatsky@gmail.com>,
"rostedt@goodmis.org" <rostedt@goodmis.org>
Subject: Re: sched: serial port lockdep warning when offlining CPUs
Date: Thu, 28 Sep 2017 20:13:26 +0900 [thread overview]
Message-ID: <20170928111325.GA30818@jagdpanzerIV.localdomain> (raw)
In-Reply-To: <20170928110428.ew5ukfihb3bdiszr@sasha-lappy>
On (09/28/17 11:04), Levin, Alexander (Sasha Levin) wrote:
> On Thu, Sep 28, 2017 at 11:38:47AM +0200, Peter Zijlstra wrote:
> >On Thu, Sep 28, 2017 at 02:19:46AM -0700, Sasha Levin wrote:
> >> Hi all,
> >>
> >> I seem to be hitting the following warning when offlining CPUs on the
> >> latest -next kernel:
> >>
> >> [289683102.607076] Unregister pv shared memory for cpu 8
> >> [289683102.622922] select_fallback_rq: 3 callbacks suppressed
> >
> >This is because you hit a printk() from the scheduler, that's known
> >broken (along with the rest of printk).
> >
> >You forgot to actually include that printk() though I suspect it reads
> >like:
> >
> > "process %d (%s) no longer affine to cpu%d\n"
> >
> >Now that uses printk_deferred() which _should_ work lots better, but
> >clearly the printk() stuff went wobbly again.
>
> Hm, so is this an actual possible lockup, or just a false positive?
a possible one.
printk() used to lockdep_off()/lockdep_on() in "dangerous places"
before, but not anymore.
-ss
next prev parent reply other threads:[~2017-09-28 11:13 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-28 9:19 Sasha Levin
2017-09-28 9:38 ` Peter Zijlstra
2017-09-28 10:30 ` Sergey Senozhatsky
2017-09-28 11:36 ` Sergey Senozhatsky
2017-09-28 11:45 ` Levin, Alexander (Sasha Levin)
2017-09-28 11:55 ` Sergey Senozhatsky
2017-09-28 12:05 ` Peter Zijlstra
2017-09-28 12:07 ` Peter Zijlstra
2017-09-28 12:15 ` Sergey Senozhatsky
2017-09-28 12:28 ` Peter Zijlstra
2017-09-28 11:47 ` Peter Zijlstra
2017-09-28 11:51 ` Sergey Senozhatsky
2017-09-28 11:04 ` Levin, Alexander (Sasha Levin)
2017-09-28 11:13 ` Sergey Senozhatsky [this message]
2017-09-28 11:38 ` Peter Zijlstra
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