Regression added by commit cd35742a (net/ethernet/arp: Let ethernet L2 managing pkt's reference while sending)

[mike-scott]

On FRDM-K64F, our upstream CI testing showed the following BUS FAULT after commit cd35742 was introduced:

PROJECT EXECUTION SUCCESSFUL
***** BUS FAULT *****
Executing thread ID (thread): 0x20002ca8
Faulting instruction address: 0x24a0a
Precise data bus error
Address: 0xbd990258
Fatal fault in essential thread! Spinning...

I will add more details once I have time to debug.

[mike-scott]

NOTE This is only on master branch and does not affect v1.9

[mike-scott]

Faulting instruction address correlates to: include/net/buf.h:1024

[mike-scott]

And verified that reverting commit cd35742 fixes the BUS FAULT

[pfalcon]

I built echo_server for frdm_k64f. It starts up ok, but on first ping received, crashes:

[dev/eth_mcux] [DBG] eth_0_init: MAC 00:04:9f:54:59:16
shell> [dev/eth_mcux] [INF] eth_mcux_phy_event: Enabled 100M full-duplex mode.
***** BUS FAULT *****
  Executing thread ID (thread): 0x20001b28
  Faulting instruction address:  0x44ce
  Precise data bus error
  Address: 0xc63cfe56
Fatal fault in essential thread! Spinning...

[pfalcon]

@tbursztyka : ^^^

(also pinged on IRC)