Kernel hang is observed when pci-hyperv module is release with device
drivers still attached. E.g. when I do 'rmmod pci_hyperv' with BCM5720
device pass-through-ed (tg3 module) I see the following:
NMI watchdog: BUG: soft lockup - CPU#1 stuck for 22s! [rmmod:2104]
...
Call Trace:
[<ffffffffa0641487>] tg3_read_mem+0x87/0x100 [tg3]
[<ffffffffa063f000>] ? 0xffffffffa063f000
[<ffffffffa0644375>] tg3_poll_fw+0x85/0x150 [tg3]
[<ffffffffa0649877>] tg3_chip_reset+0x357/0x8c0 [tg3]
[<ffffffffa064ca8b>] tg3_halt+0x3b/0x190 [tg3]
[<ffffffffa0657611>] tg3_stop+0x171/0x230 [tg3]
...
[<ffffffffa064c550>] tg3_remove_one+0x90/0x140 [tg3]
[<ffffffff813bee59>] pci_device_remove+0x39/0xc0
[<ffffffff814a3201>] __device_release_driver+0xa1/0x160
[<ffffffff814a32e3>] device_release_driver+0x23/0x30
[<ffffffff813b794a>] pci_stop_bus_device+0x8a/0xa0
[<ffffffff813b7ab6>] pci_stop_root_bus+0x36/0x60
[<ffffffffa02c3f38>] hv_pci_remove+0x238/0x260 [pci_hyperv]
The problem seems to be that we report local resources release before
stopping the bus and removing devices from it and device drivers may
try to perform some operations with these resources on shutdown. Move
resources release report after we do pci_stop_root_bus().
Signed-off-by: Vitaly Kuznetsov <[email protected]>
---
drivers/pci/host/pci-hyperv.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c
index f2559b6..c17e792 100644
--- a/drivers/pci/host/pci-hyperv.c
+++ b/drivers/pci/host/pci-hyperv.c
@@ -2268,11 +2268,6 @@ static int hv_pci_remove(struct hv_device *hdev)
hbus = hv_get_drvdata(hdev);
- ret = hv_send_resources_released(hdev);
- if (ret)
- dev_err(&hdev->device,
- "Couldn't send resources released packet(s)\n");
-
memset(&pkt.teardown_packet, 0, sizeof(pkt.teardown_packet));
init_completion(&comp_pkt.host_event);
pkt.teardown_packet.completion_func = hv_pci_generic_compl;
@@ -2295,6 +2290,11 @@ static int hv_pci_remove(struct hv_device *hdev)
pci_unlock_rescan_remove();
}
+ ret = hv_send_resources_released(hdev);
+ if (ret)
+ dev_err(&hdev->device,
+ "Couldn't send resources released packet(s)\n");
+
vmbus_close(hdev->channel);
/* Delete any children which might still exist. */
--
2.5.5
> -----Original Message-----
> From: Vitaly Kuznetsov [mailto:[email protected]]
> Sent: Friday, April 29, 2016 2:39 AM
> To: [email protected]
> Cc: [email protected]; [email protected]; KY
> Srinivasan <[email protected]>; Haiyang Zhang
> <[email protected]>; Bjorn Helgaas <[email protected]>; Jake
> Oshins <[email protected]>
> Subject: [PATCH] PCI: hv: report resources release after stopping the bus
>
> Kernel hang is observed when pci-hyperv module is release with device
> drivers still attached. E.g. when I do 'rmmod pci_hyperv' with BCM5720
> device pass-through-ed (tg3 module) I see the following:
>
> NMI watchdog: BUG: soft lockup - CPU#1 stuck for 22s! [rmmod:2104]
> ...
> Call Trace:
> [<ffffffffa0641487>] tg3_read_mem+0x87/0x100 [tg3]
> [<ffffffffa063f000>] ? 0xffffffffa063f000
> [<ffffffffa0644375>] tg3_poll_fw+0x85/0x150 [tg3]
> [<ffffffffa0649877>] tg3_chip_reset+0x357/0x8c0 [tg3]
> [<ffffffffa064ca8b>] tg3_halt+0x3b/0x190 [tg3]
> [<ffffffffa0657611>] tg3_stop+0x171/0x230 [tg3]
> ...
> [<ffffffffa064c550>] tg3_remove_one+0x90/0x140 [tg3]
> [<ffffffff813bee59>] pci_device_remove+0x39/0xc0
> [<ffffffff814a3201>] __device_release_driver+0xa1/0x160
> [<ffffffff814a32e3>] device_release_driver+0x23/0x30
> [<ffffffff813b794a>] pci_stop_bus_device+0x8a/0xa0
> [<ffffffff813b7ab6>] pci_stop_root_bus+0x36/0x60
> [<ffffffffa02c3f38>] hv_pci_remove+0x238/0x260 [pci_hyperv]
>
> The problem seems to be that we report local resources release before
> stopping the bus and removing devices from it and device drivers may
> try to perform some operations with these resources on shutdown. Move
> resources release report after we do pci_stop_root_bus().
>
> Signed-off-by: Vitaly Kuznetsov <[email protected]>
Acked-by: Jake Oshins <[email protected]>
> ---
> drivers/pci/host/pci-hyperv.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c
> index f2559b6..c17e792 100644
> --- a/drivers/pci/host/pci-hyperv.c
> +++ b/drivers/pci/host/pci-hyperv.c
> @@ -2268,11 +2268,6 @@ static int hv_pci_remove(struct hv_device *hdev)
>
> hbus = hv_get_drvdata(hdev);
>
> - ret = hv_send_resources_released(hdev);
> - if (ret)
> - dev_err(&hdev->device,
> - "Couldn't send resources released packet(s)\n");
> -
> memset(&pkt.teardown_packet, 0, sizeof(pkt.teardown_packet));
> init_completion(&comp_pkt.host_event);
> pkt.teardown_packet.completion_func = hv_pci_generic_compl;
> @@ -2295,6 +2290,11 @@ static int hv_pci_remove(struct hv_device *hdev)
> pci_unlock_rescan_remove();
> }
>
> + ret = hv_send_resources_released(hdev);
> + if (ret)
> + dev_err(&hdev->device,
> + "Couldn't send resources released packet(s)\n");
> +
> vmbus_close(hdev->channel);
>
> /* Delete any children which might still exist. */
> --
> 2.5.5
This looks like the right fix to me. Thanks.
-- Jake Oshins