Hi, netdev. I have found a bug in the Linux Kernel. Please take a look. пн, 15 янв. 2024 г. в 13:25, Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>: > > On Mon, Jan 15, 2024 at 12:19:06PM +0500, Марк Коренберг wrote: > > Kernel 6.6.9-200.fc39.x86_64 > > > > The following bash script demonstrates the problem (run under root): > > > > ``` > > #!/bin/bash > > > > set -e -u -x > > > > # Some cleanups > > ip netns delete myspace || : > > ip link del qweqwe1 || : > > > > # The bug happens only with physical interfaces, not with, say, dummy one > > ip link property add dev enp0s20f0u2 altname myname > > ip netns add myspace > > ip link set enp0s20f0u2 netns myspace > > > > # add dummy interface + set the same altname as in background namespace. > > ip link add name qweqwe1 type dummy > > ip link property add dev qweqwe1 altname myname > > > > # Trigger the bug. The kernel will try to return ethernet interface > > back to root namespace, but it can not, because of conflicting > > altnames. > > ip netns delete myspace > > > > # now `ip link` will hang forever !!!!! > > ``` > > > > I think, the problem is obvious. Althougn I don't know how to fix. > > Remove conflicting altnames for interfaces that returns from killed > > namespaces ? > > As this can only be triggered by root, not much for us to do here, > perhaps discuss it on the netdev mailing list for all network developers > to work on? > > > On kernel 6.3.8 (at least) was another bug, that allows dulicate > > altnames, and it was fixed mainline somewhere. I have another script > > to trigger the bug on these old kernels. I did not bisect. > > If this is an issue on 6.1.y, that would be good to know so that we can > try to fix the issue there if bisection can find it. Care to share the > script so that I can test? > > thanks, > > greg k-h -- Segmentation fault
