I have not been able to try out your second patch.

So once that happens you can add my name.

Cathy



On 09/27/2016 07:54 PM, Long Li wrote:
Thanks for pointing that out.

If you don't mind, I will also add "Tested-by: Cathy Avery <cav...@redhat.com>".

-----Original Message-----
From: devel [mailto:driverdev-devel-boun...@linuxdriverproject.org] On
Behalf Of Cathy Avery
Sent: Friday, September 23, 2016 4:59 AM
To: driverdev-devel@linuxdriverproject.org
Subject: Re: [PATCH 1/2 v2] pci-hyperv: properly handle pci bus remove

Hi,

You seem to be missing the Reported-by tag.

That's xiaof...@redhat.com.

Cathy

On 09/14/2016 10:10 PM, Long Li wrote:
From: Long Li <lon...@microsoft.com>

hv_pci_devices_present is called in hv_pci_remove when we remove a PCI
device from host (e.g. by disabling SRIOV on a device). In hv_pci_remove,
the bus is already removed before the call, so we don't need to rescan the
bus in the workqueue scheduled from hv_pci_devices_present. By
introducing status hv_pcibus_removed, we can avoid this situation.
The patch fixes the following kernel panic.

[  383.853124] Workqueue: events pci_devices_present_work [pci_hyperv]
[  383.853124] task: ffff88007f5f8000 ti: ffff88007f600000 task.ti:
ffff88007f600000
[  383.853124] RIP: 0010:[<ffffffff81349806>]  [<ffffffff81349806>]
pci_is_pcie+0x6/0x20
[  383.853124] RSP: 0018:ffff88007f603d38  EFLAGS: 00010206 [
383.853124] RAX: ffff88007f5f8000 RBX: 642f3d4854415056 RCX:
ffff88007f603fd8
[  383.853124] RDX: 0000000000000000 RSI: 0000000000000000 RDI:
642f3d4854415056
[  383.853124] RBP: ffff88007f603d68 R08: 0000000000000246 R09:
ffffffffa045eb9e
[  383.853124] R10: ffff88007b419a80 R11: ffffea0001c0ef40 R12:
ffff880003ee1c00
[  383.853124] R13: 63702f30303a3137 R14: 0000000000000000 R15:
0000000000000246
[  383.853124] FS:  0000000000000000(0000) GS:ffff88007b400000(0000)
knlGS:0000000000000000
[  383.853124] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [
383.853124] CR2: 00007f68b3f52350 CR3: 0000000003546000 CR4:
00000000000406f0
[  383.853124] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
0000000000000000
[  383.853124] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7:
0000000000000400
[  383.853124] Stack:
[  383.853124]  ffff88007f603d68 ffffffff8134db17 0000000000000008
ffff880003ee1c00
[  383.853124]  63702f30303a3137 ffff880003d8edb8 ffff88007f603da0
ffffffff8134ee2d [  383.853124]  ffff880003d8ed00 ffff88007f603dd8
ffff880075fec320
ffff880003d8edb8
[  383.853124] Call Trace:
[  383.853124]  [<ffffffff8134db17>] ? pci_scan_slot+0x27/0x140 [
383.853124]  [<ffffffff8134ee2d>] pci_scan_child_bus+0x3d/0x150 [
383.853124]  [<ffffffffa045ef5a>]
pci_devices_present_work+0x3ea/0x400 [pci_hyperv] [  383.853124]
[<ffffffff810a682b>] process_one_work+0x17b/0x470 [  383.853124]
[<ffffffff810a7666>] worker_thread+0x126/0x410 [  383.853124]
[<ffffffff810a7540>] ? rescuer_thread+0x460/0x460 [  383.853124]
[<ffffffff810aee1f>] kthread+0xcf/0xe0 [  383.853124]
[<ffffffff810aed50>] ?
kthread_create_on_node+0x140/0x140
[  383.853124]  [<ffffffff81699958>] ret_from_fork+0x58/0x90 [
383.853124]  [<ffffffff810aed50>] ?
kthread_create_on_node+0x140/0x140
[  383.853124] Code: 89 e5 5d 25 f0 00 00 00 c1 f8 04 c3 66 0f 1f 84
00
00 00 00 00 66 66 66 66 90 55 0f b6 47 4a 48 89 e5 5d c3 90 66 66 66
66
90 55 <80> 7f 4a 00 48 89 e5 5d 0f 95 c0 c3 0f 1f 40 00 66 2e 0f 1f 84
[  383.853124] RIP  [<ffffffff81349806>] pci_is_pcie+0x6/0x20 [
383.853124]  RSP <ffff88007f603d38>

Signed-off-by: Long Li <lon...@microsoft.com>
---
   drivers/pci/host/pci-hyperv.c | 20 +++++++++++++++++---
   1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/host/pci-hyperv.c
b/drivers/pci/host/pci-hyperv.c index a8deeca..4a37598 100644
--- a/drivers/pci/host/pci-hyperv.c
+++ b/drivers/pci/host/pci-hyperv.c
@@ -348,6 +348,7 @@ enum hv_pcibus_state {
        hv_pcibus_init = 0,
        hv_pcibus_probed,
        hv_pcibus_installed,
+       hv_pcibus_removed,
        hv_pcibus_maximum
   };

@@ -1481,13 +1482,24 @@ static void pci_devices_present_work(struct
work_struct *work)
                put_pcichild(hpdev, hv_pcidev_ref_initial);
        }

-       /* Tell the core to rescan bus because there may have been changes.
*/
-       if (hbus->state == hv_pcibus_installed) {
+       switch (hbus->state) {
+       case hv_pcibus_installed:
+               /*
+                * Tell the core to rescan bus
+                * because there may have been changes.
+                */
                pci_lock_rescan_remove();
                pci_scan_child_bus(hbus->pci_bus);
                pci_unlock_rescan_remove();
-       } else {
+               break;
+
+       case hv_pcibus_init:
+       case hv_pcibus_probed:
                survey_child_resources(hbus);
+               break;
+
+       default:
+               break;
        }

        up(&hbus->enum_sem);
@@ -2163,6 +2175,7 @@ static int hv_pci_probe(struct hv_device *hdev,
        hbus = kzalloc(sizeof(*hbus), GFP_KERNEL);
        if (!hbus)
                return -ENOMEM;
+       hbus->state = hv_pcibus_init;

        /*
         * The PCI bus "domain" is what is called "segment" in ACPI and @@
-2305,6 +2318,7 @@ static int hv_pci_remove(struct hv_device *hdev)
                pci_stop_root_bus(hbus->pci_bus);
                pci_remove_root_bus(hbus->pci_bus);
                pci_unlock_rescan_remove();
+               hbus->state = hv_pcibus_removed;
        }

        ret = hv_send_resources_released(hdev);
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