broken WoL with vanilla kernel on Debian

Question

I'm on Debian Buster/Sid, but I like to compile new vanilla kernels myself, just to try them out. However I face a recurring problem: if I use a Debian packaged kernel, Wake On Lan works correctly and I can wake my pc by sending the magic packet to it. If I use a vanilla kernel I compile myself, it doesn't.

Here is the procedure I use:

$ wget 'https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.0.2.tar.xz'
$ tar xJf linux-5.0.2.tar.xz 
$ cd linux-5.0.2/
linux-5.0.2 $ cp /boot/config-4.19.0-2-amd64 .config
linux-5.0.2 $ make oldconfig

[KCONFIG questions omitted] I eventually add something, but I never remove anything

linux-5.0.2 $ CONCURRENCY_LEVEL=20 fakeroot make-kpkg --initrd binary-arch
[...]
linux-5.0.2 $ cd..
$ su -
# dpkg -i linux-image-*.deb linux-headers-*.deb
# reboot

[... the new kernel boots ...]

# init 0

Now I try to send the magic WoL packet from another networked device, but my PC does not start. If I boot it with a Debian packaged kernel (4.19.0-2 which corresponds to upstream 4.19.16) and then shutdown it, then the WoL packet works as expected and my PC starts up.

Here is the output of lsmod, because I've been asked for it:

$ lsmod 
Module                  Size  Used by
nft_chain_route_ipv4    16384  1
xt_CHECKSUM            16384  1
nft_chain_nat_ipv4     16384  4
ipt_MASQUERADE         20480  1
xt_conntrack           16384  1
ipt_REJECT             16384  1
nf_reject_ipv4         16384  1 ipt_REJECT
nft_counter            16384  34
xt_tcpudp              20480  2
nft_compat             20480  27
devlink                73728  0
nf_tables             147456  188 nft_chain_route_ipv4,nft_compat,nft_chain_nat_ipv4,nft_counter
nfnetlink              16384  2 nft_compat,nf_tables
tun                    57344  5
bridge                188416  0
stp                    16384  1 bridge
llc                    16384  2 bridge,stp
binfmt_misc            24576  1
nls_ascii              16384  1
nls_cp437              20480  1
vfat                   24576  1
fat                    81920  1 vfat
edac_mce_amd           28672  0
kvm_amd               102400  0
ccp                    94208  1 kvm_amd
rng_core               16384  1 ccp
snd_hda_codec_realtek   122880  1
snd_hda_codec_hdmi     61440  1
kvm                   733184  1 kvm_amd
snd_hda_codec_generic    90112  1 snd_hda_codec_realtek
ledtrig_audio          16384  2 snd_hda_codec_generic,snd_hda_codec_realtek
irqbypass              16384  1 kvm
crct10dif_pclmul       16384  1
snd_hda_intel          45056  6
amdgpu               3928064  17
crc32_pclmul           16384  0
ghash_clmulni_intel    16384  0
snd_hda_codec         155648  4 snd_hda_codec_generic,snd_hda_codec_hdmi,snd_hda_intel,snd_hda_codec_realtek
joydev                 28672  0
aesni_intel           372736  0
aes_x86_64             20480  1 aesni_intel
snd_hda_core           98304  5 snd_hda_codec_generic,snd_hda_codec_hdmi,snd_hda_intel,snd_hda_codec,snd_hda_codec_realtek
crypto_simd            16384  1 aesni_intel
chash                  16384  1 amdgpu
cryptd                 24576  3 crypto_simd,ghash_clmulni_intel,aesni_intel
eeepc_wmi              16384  0
asus_wmi               32768  1 eeepc_wmi
snd_hwdep              20480  1 snd_hda_codec
sparse_keymap          16384  1 asus_wmi
snd_pcm               118784  4 snd_hda_codec_hdmi,snd_hda_intel,snd_hda_codec,snd_hda_core
rfkill                 32768  2 asus_wmi
gpu_sched              36864  1 amdgpu
glue_helper            16384  1 aesni_intel
ttm                   114688  1 amdgpu
snd_timer              45056  1 snd_pcm
drm_kms_helper        204800  1 amdgpu
video                  49152  1 asus_wmi
pcc_cpufreq            20480  0
pcspkr                 16384  0
snd                    98304  20 snd_hda_codec_generic,snd_hda_codec_hdmi,snd_hwdep,snd_hda_intel,snd_hda_codec,snd_hda_codec_realtek,snd_timer,snd_pcm
drm                   487424  12 gpu_sched,drm_kms_helper,amdgpu,ttm
evdev                  24576  31
sg                     36864  0
soundcore              16384  1 snd
i2c_algo_bit           16384  1 amdgpu
sp5100_tco             20480  0
efi_pstore             16384  0
k10temp                16384  0
efivars                20480  1 efi_pstore
fam15h_power           16384  0
button                 16384  0
acpi_cpufreq           28672  0
wmi_bmof               16384  0
mxm_wmi                16384  0
iptable_nat            16384  0
nf_nat_ipv4            16384  3 ipt_MASQUERADE,nft_chain_nat_ipv4,iptable_nat
nf_nat                 36864  1 nf_nat_ipv4
nf_conntrack          159744  4 xt_conntrack,nf_nat,ipt_MASQUERADE,nf_nat_ipv4
nf_defrag_ipv6         24576  1 nf_conntrack
nf_defrag_ipv4         16384  1 nf_conntrack
ecryptfs              122880  0
parport_pc             32768  0
ppdev                  24576  0
nfsd                  425984  13
lp                     20480  0
auth_rpcgss            69632  1 nfsd
nfs_acl                16384  1 nfsd
lockd                 118784  1 nfsd
parport                61440  3 parport_pc,lp,ppdev
grace                  16384  2 nfsd,lockd
sunrpc                421888  18 nfsd,auth_rpcgss,lockd,nfs_acl
efivarfs               16384  1
ip_tables              28672  1 iptable_nat
x_tables               49152  7 xt_conntrack,nft_compat,xt_tcpudp,ipt_MASQUERADE,xt_CHECKSUM,ipt_REJECT,ip_tables
autofs4                49152  2
ext4                  733184  2
crc16                  16384  1 ext4
mbcache                16384  1 ext4
jbd2                  126976  1 ext4
fscrypto               36864  1 ext4
dm_mod                151552  3
hid_generic            16384  0
usbhid                 61440  0
hid                   147456  2 usbhid,hid_generic
raid10                 65536  1
sd_mod                 53248  13
raid456               176128  0
async_raid6_recov      24576  1 raid456
async_memcpy           20480  2 raid456,async_raid6_recov
async_pq               20480  2 raid456,async_raid6_recov
async_xor              20480  3 async_pq,raid456,async_raid6_recov
async_tx               20480  5 async_pq,async_memcpy,async_xor,raid456,async_raid6_recov
xor                    24576  1 async_xor
raid6_pq              122880  3 async_pq,raid456,async_raid6_recov
libcrc32c              16384  3 nf_conntrack,nf_nat,raid456
crc32c_generic         16384  0
raid1                  49152  1
raid0                  24576  1
multipath              20480  0
linear                 20480  0
md_mod                167936  8 raid1,raid10,raid0,linear,raid456,multipath
ohci_pci               20480  0
ahci                   40960  9
libahci                40960  1 ahci
xhci_pci               20480  0
ohci_hcd               57344  1 ohci_pci
ehci_pci               20480  0
libata                278528  2 libahci,ahci
crc32c_intel           24576  3
r8169                  90112  0
xhci_hcd              258048  1 xhci_pci
realtek                20480  1
ehci_hcd               94208  1 ehci_pci
libphy                 86016  2 r8169,realtek
i2c_piix4              28672  0
usbcore               286720  7 xhci_hcd,ohci_hcd,ehci_pci,usbhid,ehci_hcd,xhci_pci,ohci_pci
scsi_mod              241664  3 sd_mod,libata,sg
wmi                    36864  3 asus_wmi,wmi_bmof,mxm_wmi

And here are the modules configurations in /etc/modprobe.d/:

blacklist microcode
blacklist radeon
options md_mod start_ro=1
options cirrus modeset=1
options mgag200 modeset=1

What am I missing?

Answer 1

As you are using the Realtek module (r8169), I believe this is expected behavior before commit fa6821c (r8169: improve WoL handling). After a bit of back and forth, the driver ended up delegating the choice to userspace, with only the referred last commit restoring previously known behavior:

In addition we report WoL as being disabled in get_wol, matching
that device isn't wakeup-enabled.

Meaning with the version you are using, your systemd sees WoL as already setup, when it might still have to request that.

Of course the user still has the option to override this with e.g. ethtool.

So you just need to test WoL after this manual step. Replace g if you are using a different wakeup packet, replace enp1s0 if your network interface as a different name:

root@machine:~ # ethtool -s enp1s0 wol g

If this manual setup works with your current 5.0.2 build, you can expect a future kernel version (or HEAD, right now) to reflect your systemd configuration as well.