[Intel-wired-lan] [Bug 215129] New: Linux kernel hangs during power down
Heiner Kallweit
hkallweit1 at gmail.com
Thu Nov 25 21:11:16 UTC 2021
On 25.11.2021 08:32, Heiner Kallweit wrote:
> On 25.11.2021 01:46, Jakub Kicinski wrote:
>> Adding Kalle and Hainer.
>>
>> On Wed, 24 Nov 2021 14:45:05 -0800 Stephen Hemminger wrote:
>>> Begin forwarded message:
>>>
>>> Date: Wed, 24 Nov 2021 21:14:53 +0000
>>> From: bugzilla-daemon at bugzilla.kernel.org
>>> To: stephen at networkplumber.org
>>> Subject: [Bug 215129] New: Linux kernel hangs during power down
>>>
>>>
>>> https://bugzilla.kernel.org/show_bug.cgi?id=215129
>>>
>>> Bug ID: 215129
>>> Summary: Linux kernel hangs during power down
>>> Product: Networking
>>> Version: 2.5
>>> Kernel Version: 5.15
>>> Hardware: All
>>> OS: Linux
>>> Tree: Mainline
>>> Status: NEW
>>> Severity: normal
>>> Priority: P1
>>> Component: Other
>>> Assignee: stephen at networkplumber.org
>>> Reporter: martin.stolpe at gmail.com
>>> Regression: No
>>>
>>> Created attachment 299703
>>> --> https://bugzilla.kernel.org/attachment.cgi?id=299703&action=edit
>>> Kernel log after timeout occured
>>>
>>> On my system the kernel is waiting for a task during shutdown which doesn't
>>> complete.
>>>
>>> The commit which causes this behavior is:
>>> [f32a213765739f2a1db319346799f130a3d08820] ethtool: runtime-resume netdev
>>> parent before ethtool ioctl ops
>>>
>>> This bug causes also that the system gets unresponsive after starting Steam:
>>> https://steamcommunity.com/app/221410/discussions/2/3194736442566303600/
>>>
>>
>
> I think the reference to ath10k_pci is misleading, Kalle isn't needed here.
> The actual issue is a RTNL deadlock in igb_resume(). See log snippet:
>
> Nov 24 18:56:19 MartinsPc kernel: igb_resume+0xff/0x1e0 [igb 21bf6a00cb1f20e9b0e8434f7f8748a0504e93f8]
> Nov 24 18:56:19 MartinsPc kernel: pci_pm_runtime_resume+0xa7/0xd0
> Nov 24 18:56:19 MartinsPc kernel: ? pci_pm_freeze_noirq+0x110/0x110
> Nov 24 18:56:19 MartinsPc kernel: __rpm_callback+0x41/0x120
> Nov 24 18:56:19 MartinsPc kernel: ? pci_pm_freeze_noirq+0x110/0x110
> Nov 24 18:56:19 MartinsPc kernel: rpm_callback+0x35/0x70
> Nov 24 18:56:19 MartinsPc kernel: rpm_resume+0x567/0x810
> Nov 24 18:56:19 MartinsPc kernel: __pm_runtime_resume+0x4a/0x80
> Nov 24 18:56:19 MartinsPc kernel: dev_ethtool+0xd4/0x2d80
>
> We have at least two places in net core where runtime_resume() is called
> under RTNL. This conflicts with the current structure in few Intel drivers
> that have something like the following in their resume path.
>
> rtnl_lock();
> if (!err && netif_running(netdev))
> err = __igb_open(netdev, true);
>
> if (!err)
> netif_device_attach(netdev);
> rtnl_unlock();
>
> Other drivers don't do this, so it's the question whether it's actually
> needed here to take RTNL. Some discussion was started [0], but it ended
> w/o tangible result and since then it has been surprisingly quiet.
>
> [0] https://www.spinics.net/lists/netdev/msg736880.html
>
I think the problem with runtime_resume() taking RTNL could also hit
the driver internally. See following call chain: If this would ever
be called when the device is runtime-suspended, then a similar
deadlock would occur.
__dev_open() - called with RTNL held
igb_open()
__igb_open() - arg resuming is false
if (!resuming)
pm_runtime_get_sync(&pdev->dev);
igb_resume()
rtnl_lock()
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