netdev - Re: [Xen-devel] printk from softirq on xen: hard lockup

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: <55C330C7.6050204@citrix.com>
Date:	Thu, 6 Aug 2015 11:02:47 +0100
From:	David Vrabel <david.vrabel@...rix.com>
To:	"Jason A. Donenfeld" <Jason@...c4.com>,
	David Vrabel <david.vrabel@...rix.com>
CC:	<netdev@...r.kernel.org>,
	Paul McKenney <paulmck@...ux.vnet.ibm.com>,
	<linux-kernel@...r.kernel.org>, <xen-devel@...ts.xen.org>
Subject: Re: [Xen-devel] printk from softirq on xen: hard lockup

On 05/08/15 00:01, Jason A. Donenfeld wrote:
> Hey David,
> 
> Sorry for the premature response on my phone earlier. Real reply follows.
>>> rcu_read_lock, when using Xen PV. Relevant excerpts of the
>>                                 ^^  PV guest?
> 
> Yes. The lockup occurs on a PV guest. Nothing special at all about the
> configuration. Vanilla upstream 4.1.3 kernel.
> 
>>> __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?
> 
> That's odd. It's a PV guest, not an HVM nor PVH guest.

Linux PV guests must use the "Xen PV" APIC driver.  You need to
investigate why your PV guest is not using this (although I'm surprised
it works at all with the wrong one).

David
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html