Re: [Xen-devel] Xen pci-passthrough problem with pci-detach and pci-assignable-remove

[Sander Eikelenboom <linux@xxxxxxxxxxxxxx>]

Friday, January 24, 2014, 6:48:06 PM, you wrote:

> On Fri, Jan 24, 2014 at 02:36:02PM +0100, Sander Eikelenboom wrote:
>> 
>> Friday, January 10, 2014, 6:38:10 PM, you wrote:
>> 
>> >> > Wow. You just walked in a pile of bugs didn't you? And on Friday
>> >> > nonethless.
>> >> 
>> >> As usual ;-)
>> 
>> > Ha!
>> > ..snip..
>> >> >> [  489.082358]  [<ffffffff81087ac6>] ? mutex_spin_on_owner+0x38/0x45
>> >> >> [  489.106272]  [<ffffffff818e5e22>] ? 
>> >> >> schedule_preempt_disabled+0x6/0x9
>> >> >> [  489.130158]  [<ffffffff818e7034>] ? 
>> >> >> __mutex_lock_slowpath+0x159/0x1b5
>> >> >> [  489.154147]  [<ffffffff818e70a6>] ? mutex_lock+0x16/0x25
>> >> >> [  489.177890]  [<ffffffff8135972d>] ? pci_reset_function+0x26/0x4e
>> >> 
>> >> > Yeah, that bug my RFC patchset (the one that does the slot/bus reset) 
>> >> > should also fix.
>> >> > I totally forgot about it !
>> >> 
>> >> Got a link to that patchset ?
>> 
>> > https://lkml.org/lkml/2013/12/13/315
>> 
>> >> I at least could give it a spin .. you never know when fortune is on your 
>> >> side :-)
>> 
>> > It is also at this git tree:
>> 
>> > git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen.git and the
>> > branch name is "devel/xen-pciback.slot_and_bus.v0". You will likely
>> > want to merge it in your current Linus tree.
>> 
>> > Thank you!
>> 
>> 
>> Hi Konrad,
>> 
>> Just got time to test this some more, when merging this branch *except* the 
>> last commit (9599a5ad38a3bb250e996ccb2cdaab6fb68aaacd)
>> seems to help with my problem,i'm no capable of using:
>> - xl pci-detach
>> - xl pci-assignable-remove
>> - echo "BDF" > /sys/bus/pci/drivers/<devicename>/bind
>> 
>> to remove a pci device from a running HVM guest and rebinding it to a driver 
>> in dom0 without those nasty stacktraces :-)
>> So the first 4 seem to be an improvement.
>> 
>> That last commit (9599a5ad38a3bb250e996ccb2cdaab6fb68aaacd) seems to give 
>> troubles of it's own.

> Could you email me your lspci output and also which devices you move/switch 
> etc?

Hmm hope you didn't misunderstood :-) I now spot a missing "w" .. i am noW 
capable of .. :-)
So it works when the first 4 patches of that branch are applied, I tried with 
both a NIC and a wireless NIC and had no problems.

The problems with that last commit don't seem to be related to that 
moving/switch of devices it also occurs
on a more regular create or shutdown of a guest with a device passed through to 
it.

Just to be complete here is a stacktrace of the hung task i encounter then:

[  968.600248] INFO: task xenwatch:29 blocked for more than 120 seconds.
[  968.601885]       Not tainted 3.13.020140123-pcireset-p5+ #1
[  968.603086] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this 
message.
[  968.605298] xenwatch        D ffff88003fb6c1d0     0    29      2 0x00000000
[  968.607007]  ffff88003fb6c1d0 0000000000000246 ffffffff81a0af60 
ffff880038c8a980
[  968.608773]  0000000000013f00 0000000000013f00 ffff88003fb6c1d0 
ffff88003fb9bfd8
[  968.609515]  ffff88003fb6c1d0 7fffffffffffffff 7fffffffffffffff 
0000000000000002
[  968.610260] Call Trace:
[  968.610493]  [<ffffffff818eda68>] ? 
genl_set_err.isra.15.constprop.21+0x51/0x51
[  968.611163]  [<ffffffff818eda94>] ? schedule_timeout+0x2c/0x123
[  968.641854]  [<ffffffff813e8bc5>] ? read_reply+0xcc/0xd8
[  968.666733]  [<ffffffff81117c2f>] ? kfree+0x50/0x6f
[  968.691593]  [<ffffffff81116d5b>] ? arch_local_irq_restore+0x7/0x8
[  968.716408]  [<ffffffff813e8bc5>] ? read_reply+0xcc/0xd8
[  968.740956]  [<ffffffff81087ecf>] ? arch_local_irq_disable+0x7/0x8
[  968.765631]  [<ffffffff818eebc3>] ? __wait_for_common+0x123/0x15e
[  968.790148]  [<ffffffff8107d188>] ? try_to_wake_up+0x198/0x198
[  968.814917]  [<ffffffff818f061e>] ? _raw_spin_unlock_irqrestore+0xb/0xc
[  968.839656]  [<ffffffff813f18c1>] ? pcistub_get_pci_dev_by_slot+0xc3/0xd5
[  968.864307]  [<ffffffff813f27f4>] ? xen_pcibk_export_device+0x27/0xfe
[  968.888824]  [<ffffffff813f2a10>] ? xen_pcibk_setup_backend+0x145/0x265
[  968.913094]  [<ffffffff813f300d>] ? xen_pcibk_xenbus_probe+0xeb/0x12a
[  968.937093]  [<ffffffff813ea6b8>] ? xenbus_dev_probe+0x56/0xb5
[  968.961314]  [<ffffffff814cbd9b>] ? __driver_attach+0x73/0x73
[  968.985750]  [<ffffffff814cbc07>] ? driver_probe_device+0x92/0x1b3
[  969.010282]  [<ffffffff814ca434>] ? bus_for_each_drv+0x46/0x80
[  969.034570]  [<ffffffff814cbb40>] ? device_attach+0x68/0x86
[  969.058685]  [<ffffffff814cb22b>] ? bus_probe_device+0x2c/0x9d
[  969.082670]  [<ffffffff814c99b3>] ? device_add+0x371/0x51c
[  969.106462]  [<ffffffff8106339e>] ? init_timer_key+0xe/0x5a
[  969.130155]  [<ffffffff813ea39c>] ? xenbus_probe_node+0x121/0x160
[  969.153793]  [<ffffffff813e9369>] ? xenbus_dev_request_and_reply+0x75/0x75
[  969.177396]  [<ffffffff813ea550>] ? xenbus_dev_changed+0x175/0x1a4
[  969.200938]  [<ffffffff813e9431>] ? xenwatch_thread+0xc8/0xf2
[  969.224678]  [<ffffffff813e9369>] ? xenbus_dev_request_and_reply+0x75/0x75
[  969.248560]  [<ffffffff81085072>] ? bit_waitqueue+0x82/0x82
[  969.272249]  [<ffffffff810728e6>] ? kthread+0x99/0xa1
[  969.296128]  [<ffffffff8100384f>] ? xen_mc_issue.constprop.20+0x27/0x4d
[  969.320029]  [<ffffffff81070000>] ? get_task_pid+0x2a/0x2c
[  969.343706]  [<ffffffff8107284d>] ? __kthread_parkme+0x59/0x59
[  969.367233]  [<ffffffff818f598c>] ? ret_from_fork+0x7c/0xb0
[  969.390736]  [<ffffffff8107284d>] ? __kthread_parkme+0x59/0x59



> Thanks!
>> 
>> --
>> Sander
>> 



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