Re: panic: syncache: mbuf too small

On Tue, 8 Feb 2022, Drew Gallatin wrote:

> Can you examine max_linkhdr?

Yes, was still sitting in ddb (thankfully watchdog got disabled):

db> x max_linkhdr
max_linkhdr:    58

And for consistency checks:

db> x max_hdr
max_hdr:        94
db> x max_datalen
max_datalen:    14
db> x max_protohdr
max_protohdr:   3c

db> show reg
cs                        0x20
ds                        0x3b
es                        0x3b
fs                        0x13
gs                        0x1b
ss                        0x28
rax                       0x12
rcx                        0x1
rdx         0xffffffff811f6d0a
rbx         0xffffffff812e614c
rsp         0xfffffe0007fa15a0
rbp         0xfffffe0007fa15b0
rsi                       0x80
rdi         0xffffffff81e8cec0  cnputs_mtx
r8                        0x10
r9                       0x1d0
r10         0xffffffff81cfa820  vga_conssoftc
r11                       0x10
r12         0xffffffff812961ab
r13                       0x28
r14                      0x100
r15         0xfffffe000937a740
rip         0xffffffff80c545a7  kdb_enter+0x37
rflags                    0x86
kdb_enter+0x37: movq    $0,0x1283a5e(%rip)

Found a console log;  the system was idle, right after a boot for a few minutes.
It's a lab machine having booted off IPv4 (grml) but also having IPv6 on
the network.

According to terminal backlogs it was an incoming IPv6 ssh session likely
to have triggered this.  Always great if things are "idle" and only few people
to ask.

it is amd64;  main @ 773e3a71b2f11d422694495aca988d4c7143601b from Jan 31st.

/bz


> Drew
>
> On Tue, Feb 8, 2022 at 1:58 PM Bjoern A. Zeeb <
> bzeeb-lists@lists.zabbadoz.net> wrote:
>
>> Hi,
>>
>> I just came to a console finding this.  The tree is from a few days ago;
>> is this known or should I investigate if it happens again?   I sadly cannot
>> dump on this machine.
>>
>> /bz
>>
>> db> show panic
>> panic: syncache: mbuf too small
>> db> where
>> Tracing pid 0 tid 100014 td 0xfffffe000937a740
>> kdb_enter() at kdb_enter+0x37/frame 0xfffffe0007fa15b0
>> vpanic() at vpanic+0x1b0/frame 0xfffffe0007fa1600
>> panic() at panic+0x43/frame 0xfffffe0007fa1660
>> syncache_respond() at syncache_respond+0x777/frame 0xfffffe0007fa1730
>> syncache_add() at syncache_add+0xa71/frame 0xfffffe0007fa18c0
>> tcp_input_with_port() at tcp_input_with_port+0x14f5/frame
>> 0xfffffe0007fa1a20
>> tcp6_input_with_port() at tcp6_input_with_port+0x69/frame
>> 0xfffffe0007fa1a50
>> tcp6_input() at tcp6_input+0xb/frame 0xfffffe0007fa1a60
>> ip6_input() at ip6_input+0xc2f/frame 0xfffffe0007fa1b40
>> netisr_dispatch_src() at netisr_dispatch_src+0xaf/frame 0xfffffe0007fa1ba0
>> ether_demux() at ether_demux+0x16e/frame 0xfffffe0007fa1bd0
>> ether_nh_input() at ether_nh_input+0x3fc/frame 0xfffffe0007fa1c30
>> netisr_dispatch_src() at netisr_dispatch_src+0xaf/frame 0xfffffe0007fa1c90
>> ether_input() at ether_input+0x99/frame 0xfffffe0007fa1cf0
>> iflib_rxeof() at iflib_rxeof+0xcb3/frame 0xfffffe0007fa1e00
>> _task_fn_rx() at _task_fn_rx+0x7a/frame 0xfffffe0007fa1e40
>> gtaskqueue_run_locked() at gtaskqueue_run_locked+0xa7/frame
>> 0xfffffe0007fa1ec0
>> gtaskqueue_thread_loop() at gtaskqueue_thread_loop+0xc2/frame
>> 0xfffffe0007fa1ef0
>> fork_exit() at fork_exit+0x80/frame 0xfffffe0007fa1f30
>> fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe0007fa1f30
>> --- trap 0, rip = 0, rsp = 0, rbp = 0 ---
>>
>>
>> --
>> Bjoern A. Zeeb                                                     r15:7
>>
>>
>

-- 
Bjoern A. Zeeb                                                     r15:7