Subject: Re: [regression] Kernel OOPS on boot with Kernel 6.3(.1) and RTL8153 Gigabit Ethernet Adapter

From: Jakub Kicinski <[email-masked]>
Date: Fri, 5 May 2023 12:04:36 -0700

On Fri, 05 May 2023 12:16:48 +0200 Bjørn Mork wrote:
> "Linux regression tracking (Thorsten Leemhuis)"
> <[email-masked]> writes:
> 
> >> Kernel OOPS on boot
> >> 
> >> Hello,
> >> 
> >> on my laptop with kernel 6.3.0 and 6.3.1 fails to correctly boot if the usb-c device "RTL8153 Gigabit Ethernet Adapter" is connected.
> >> 
> >> If I unplug it, boot and the plug it in, everything works fine.
> >> 
> >> This used to work fine with 6.2.10.
> >> 
> >> HW:
> >> - Dell Inc. Latitude 7410/0M5G57, BIOS 1.22.0 03/20/2023
> >> - Realtek Semiconductor Corp. RTL8153 Gigabit Ethernet Adapter
> >> 
> >> 
> >> Call Trace (manually typed from the image, typos maybe be included)
> >> - bpf_dev_bound_netdev_unregister
> >> - unregister_netdevice_many_notify
> >> - unregister_netdevice_gueue
> >> - unregister_netdev
> >> - usbnet_disconnect
> >> - usb_unbind_interface
> >> - device_release_driver_internal
> >> - bus_remove_device
> >> - device_del
> >> - ? kobject_put
> >> - usb_disable_device
> >> - usb_set_configuration
> >> - rt18152_cfgselector_probe
> >> - usb_probe_device
> >> - really_probe
> >> - ? driver_probe_device
> >> - ...  
> 
> 
> Ouch. This is obviously related to the change I made to the RTL8153
> driver, which you can see is in effect by the call to
> rtl8152_cfgselector_probe above (compensating for the typo).
> 
> But to me it doesn't look like the bug is in that driver. It seems we
> are triggering some latent bug in the unregister_netdev code?
> 
> The trace looks precise enogh to me.  The image also shows
> 
>  RIP: 0010: __rhastable_lookup.constprop.0+0x18/0x120
> 
> which I believe comes from bpf_dev_bound_netdev_unregister() calling the
> bpf_offload_find_netdev(), which does:
> 
> 
> bpf_offload_find_netdev(struct net_device *netdev)
> {
>         lockdep_assert_held(&bpf_devs_lock);
> 
>         return rhashtable_lookup_fast(&offdevs, &netdev, offdevs_params);
> }
> 
> 
> Maybe someone familiar with that code can explain why this fails if called
> at boot instead of later?
> 
> AFAICS, we don't do anything out of the ordinary in that driver, with
> respect to netdev registration at least.  A similar device disconnet and
> netdev unregister would also happen if you decided to pull the USB
> device from the port during boot.  In fact, most USB network devices
> behave similar when disconnected and there is nothing preventing it
> from happening while the system is booting..

Yeah, I think it's because late_initcall is too conservative. 
The device gets removed before late_initcall(). 

It's just a hashtable init, I think that we can do:

diff --git a/kernel/bpf/offload.c b/kernel/bpf/offload.c
index d9c9f45e3529..8a26cd8814c1 100644
--- a/kernel/bpf/offload.c
+++ b/kernel/bpf/offload.c
@@ -859,4 +859,4 @@ static int __init bpf_offload_init(void)
 	return rhashtable_init(&offdevs, &offdevs_params);
 }
 
-late_initcall(bpf_offload_init);
+core_initcall(bpf_offload_init);

Thorsten, how is the communication supposed to work in this case?
Can you ask the reporter to test this? I don't see them on CC...