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From: Dario Faggioli <dario.faggioli@citrix.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Chao Peng <chao.p.peng@linux.intel.com>,
	boris.ostrovsky@oracle.com, keir@xen.org, JBeulich@suse.com,
	xen-devel@lists.xen.org
Subject: Re: [PATCH v3] x86: correct socket_cpumask allocation
Date: Fri, 10 Jul 2015 16:57:15 +0200	[thread overview]
Message-ID: <1436540235.22672.425.camel@citrix.com> (raw)
In-Reply-To: <559FDB1A.8030402@citrix.com>


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On Fri, 2015-07-10 at 15:47 +0100, Andrew Cooper wrote:
> On 10/07/15 15:29, Dario Faggioli wrote:

> > (XEN) Xen call trace:
> > (XEN)    [<ffff82d0801886aa>] cpu_smpboot_free+0x2b/0x255
> > (XEN)    [<ffff82d080189225>] cpu_smpboot_callback+0x317/0x327
> > (XEN)    [<ffff82d08011c019>] notifier_call_chain+0x67/0x87
> > (XEN)    [<ffff82d08010153e>] cpu_down+0xd9/0x12c
> > (XEN)    [<ffff82d080101744>] disable_nonboot_cpus+0x93/0x138
> > (XEN)    [<ffff82d0801a8967>] enter_state_helper+0xbd/0x365
> > (XEN)    [<ffff82d080106212>] continue_hypercall_tasklet_handler+0x4a/0xb1
> > (XEN)    [<ffff82d08012f8ae>] do_tasklet_work+0x78/0xab
> > (XEN)    [<ffff82d08012fbe4>] do_tasklet+0x5e/0x8a
> > (XEN)    [<ffff82d0801617e0>] idle_loop+0x56/0x6b
> > (XEN) 
> > (XEN) Pagetable walk from ffff830b2072a5b8:
> > (XEN)  L4[0x106] = 00000000dba9a063 ffffffffffffffff
> > (XEN)  L3[0x02c] = 0000000000000000 ffffffffffffffff
> > (XEN) 
> > (XEN) ****************************************
> > (XEN) Panic on CPU 0:
> > (XEN) FATAL PAGE FAULT
> > (XEN) [error_code=0000]
> > (XEN) Faulting linear address: ffff830b2072a5b8
> > (XEN) ****************************************
> 
> Confirmed - this is also an issue for me.  It is only shutdown; reboot
> appears to be fine.
> 
I added this printk:

printk("  cpu=%u cpu_to_socket=%u\n", cpu, socket);

Right before this chunk of code, in cpu_smpboot_free():

    if ( cpumask_empty(socket_cpumask[socket]) )
    {
        xfree(socket_cpumask[socket]);
        socket_cpumask[socket] = NULL;
    }

And it says this:

...
(XEN) Preparing system for ACPI S5 state.
(XEN) Disabling non-boot CPUs ...
(XEN) Broke affinity for irq 9
(XEN)   cpu=1 cpu_to_socket=4294967295
(XEN) ----[ Xen-4.6-unstable  x86_64  debug=y  Tainted:    C ]----
(XEN) CPU:    0
(XEN) RIP:    e008:[<ffff82d0801886c2>] cpu_smpboot_free+0x43/0x28b
...

I.e., it looks like phys_proc_id has already been reset to
XEN_INVALID_SOCKET_ID, as we're kind-of racing with
remove_siblinginfo().

I'll keep looking, but not for too long... Chao, ping?

Dario
-- 
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)

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  reply	other threads:[~2015-07-10 14:57 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-07-09 14:23 [PATCH v3] x86: correct socket_cpumask allocation Chao Peng
2015-07-09 15:16 ` Andrew Cooper
2015-07-09 15:36   ` Boris Ostrovsky
2015-07-10 14:29 ` Dario Faggioli
2015-07-10 14:47   ` Andrew Cooper
2015-07-10 14:57     ` Dario Faggioli [this message]
2015-07-10 15:13       ` Jan Beulich
2015-07-10 15:25         ` Jan Beulich
2015-07-10 16:03           ` Dario Faggioli
2015-07-13  3:19             ` Chao Peng
2015-07-10 15:33         ` Dario Faggioli

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