Subject: Regression in add xfrm interface

From: Stephen Hemminger <[email-masked]>
Date: Mon, 7 Mar 2022 12:11:23 -0800

There appears to be a regression between 5.10 (Debian 11) and 5.16 (Debian testing)
kernel in handling of ip link xfrm create. This shows up in the iproute2 testsuite
which now fails. This is kernel (not iproute2) regression.

Running ip/link/add_type_xfrm.t [iproute2-this/5.16.0-1-amd64]: FAILED

Good log:
::::::::::::::
link/add_type_xfrm.t.iproute2-this.out
::::::::::::::
[Testing Add XFRM Interface, With IF-ID]
tests/ip/link/add_type_xfrm.t: Add dev-ktyXSm xfrm interface succeeded
tests/ip/link/add_type_xfrm.t: Show dev-ktyXSm xfrm interface succeeded with output:
2: dev-ktyXSm@lo: <NOARP,M-DOWN> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/none  promiscuity 0 minmtu 68 maxmtu 65535 
    xfrm if_id 0xf addrgenmode eui64 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535 
test on: "dev-ktyXSm" [SUCCESS]
test on: "if_id 0xf" [SUCCESS]
tests/ip/link/add_type_xfrm.t: Del dev-ktyXSm xfrm interface succeeded
[Testing Add XFRM Interface, No IF-ID]
tests/ip/link/add_type_xfrm.t: Add dev-tkUDaA xfrm interface succeeded
tests/ip/link/add_type_xfrm.t: Show dev-tkUDaA xfrm interface succeeded with output:
3: dev-tkUDaA@lo: <NOARP,M-DOWN> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/none  promiscuity 0 minmtu 68 maxmtu 65535 
    xfrm if_id 0 addrgenmode eui64 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535 
test on: "dev-tkUDaA" [SUCCESS]
test on: "if_id 0xf" [SUCCESS]
tests/ip/link/add_type_xfrm.t: Del dev-tkUDaA xfrm interface succeeded

Failed log:

[Testing Add XFRM Interface, With IF-ID]
tests/ip/link/add_type_xfrm.t: Add dev-pxNsUc xfrm interface succeeded
tests/ip/link/add_type_xfrm.t: Show dev-pxNsUc xfrm interface succeeded with output:
2: dev-pxNsUc@lo: <NOARP,M-DOWN> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/none  promiscuity 0 minmtu 68 maxmtu 65535 
    xfrm if_id 0xf addrgenmode eui64 numtxqueues 1 numrxqueues 1 gso_max_size 65536 gso_max_segs 65535 
test on: "dev-pxNsUc" [SUCCESS]
test on: "if_id 0xf" [SUCCESS]
tests/ip/link/add_type_xfrm.t: Del dev-pxNsUc xfrm interface succeeded
[Testing Add XFRM Interface, No IF-ID]
test on: "dev-dSwSKP" [FAILED]
test on: "if_id 0xf" [FAILED]