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From: David Vrabel <david.vrabel@citrix.com>
To: "Jason A. Donenfeld" <Jason@zx2c4.com>,
	<linux-kernel@vger.kernel.org>, <netdev@vger.kernel.org>,
	<xen-devel@lists.xen.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Subject: Re: [Xen-devel] printk from softirq on xen: hard lockup
Date: Tue, 4 Aug 2015 18:12:49 +0100	[thread overview]
Message-ID: <55C0F291.7060806@citrix.com> (raw)
In-Reply-To: <CAHmME9rUdafnjz0ej-z_cgznMrj27SJgy6v8GJXM0qGfUpWaMQ@mail.gmail.com>

On 04/08/15 17:41, Jason A. Donenfeld wrote:
> Hi folks,
> 
> Paul McKenney and I had an offline discussion about some rcu questions
> that eventually lead into me investigating a strange full lock-up I'm
> experiencing as a consequence of a printk in softirq inside of an
> rcu_read_lock, when using Xen PV. Relevant excerpts of the
                                ^^  PV guest?

> (gdb) target remote localhost:9999
> Remote debugging using localhost:9999
> __xapic_wait_icr_idle () at ./arch/x86/include/asm/ipi.h:56
> 56              while (native_apic_mem_read(APIC_ICR) & APIC_ICR_BUSY)
                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  => HVM guest

Which is it?

A HVM guest's serial console may be particularly slow (since it's
emulated by qemu).  Try using the PV console?

David

  reply	other threads:[~2015-08-04 17:12 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-08-04 16:41 printk from softirq on xen: hard lockup Jason A. Donenfeld
2015-08-04 17:12 ` David Vrabel [this message]
2015-08-04 17:45   ` Jason A. Donenfeld
2015-08-04 23:01   ` [Xen-devel] " Jason A. Donenfeld
2015-08-06 10:02     ` David Vrabel
2015-08-06 15:58       ` Jason A. Donenfeld
2015-08-06 16:10         ` David Vrabel
2015-08-06 16:21           ` Jason A. Donenfeld
2015-08-06 16:29             ` [PATCH] xen-apic: Enable on domU as well Jason A. Donenfeld
2015-08-06 16:37               ` [PATCH v2] " Jason A. Donenfeld
2015-08-07 14:23                 ` [Xen-devel] " Konrad Rzeszutek Wilk
2015-08-07 14:37                   ` Jason A. Donenfeld
2015-08-10 13:40                 ` [PATCH v3] " Jason A. Donenfeld
2015-08-10 13:41                   ` David Vrabel
2015-08-10 13:44                     ` Jason A. Donenfeld
2015-08-11 10:46                   ` [Xen-devel] " David Vrabel
2015-08-05 16:37   ` [Xen-devel] printk from softirq on xen: hard lockup Jason A. Donenfeld
2015-08-06  8:22   ` Ian Campbell

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