Bartek wrote:
> Hopefully, this time it my bug report should be ok :):
> 
> Apr 11 23:53:38 localhost pppd[31289]: rcvd [proto=0x7689] e1 cd 33 f6
> fd f7 52 e6 58 c9 73 98 bc ff ad d5 b5 a3 e5 d9 1e 77 76 0a 1c 87 59
> bf 44 cc ac 3b ...
> Apr 11 23:53:38 localhost pppd[31289]: Unsupported protocol 0x7689 received
> Apr 11 23:53:38 localhost pppd[31289]: sent [LCP ProtRej id=0x9 76 89
> e1 cd 33 f6 fd f7 52 e6 58 c9 73 98 bc ff ad d5 b5 a3 e5 d9 1e 77 76
> 0a 1c 87 59 bf 44 cc ...]
> Apr 11 23:53:38 localhost pppd[31289]: rcvd [proto=0xda7d] 15 19 45 3c
> e0 ac 44 92 3b c4 8e 75 6b b8 4a 9f 4a 3a 22 63 d3 a1 56 98 47 62 bc
> cd a6 8e d5 77 ...
> Apr 11 23:53:38 localhost pppd[31289]: Unsupported protocol 0xda7d received
> Apr 11 23:53:38 localhost pppd[31289]: sent [LCP ProtRej id=0xa da 7d
> 15 19 45 3c e0 ac 44 92 3b c4 8e 75 6b b8 4a 9f 4a 3a 22 63 d3 a1 56
> 98 47 62 bc cd a6 8e ...]
> Apr 11 23:53:40 localhost kernel: skb_under_panic: text:f8c62c0e
> len:291 put:1 head:ddc94800 data:ddc947ff tail:ddc94922 end:ddc94e00
> dev:<NULL>


It seems we fail to reserve enough headroom for the case
buf[0] == PPP_ALLSTATIONS and buf[1] != PPP_UI.

Can you try this patch please?