panic: sbflush_internal: cc 4294966301 || mb 0 || mbcnt 0

[Florian C. Smeets]

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Bruce M. Simpson wrote:
> I was able to reproduce this bug, although the circumstances under which
> I did it are weird.
> 
> I have two NICs on the same box patched to the same Ethernet broadcast
> domain, but on interconnected switches with no spanning tree. If I stop
> VLAN_HWTAGGING on msk with a vlan interface attached, and then run ping
> -f to a local host via the network configured on fxp, it seems to
> trigger the problem.
> 
> sb_cc is always 84 bytes, which is 20 bytes IPv4 header + 64 bytes of
> ICMP data, so it's definitely ping which is triggering the issue in my
> case. I haven't been able to get a clean dump yet as my 6.2-RELEASE
> userland doesn't seem to understand -CURRENT's minidumps.
> 

I hit this panic again, this time it seems i could get some useful
output from it

panic: sbflush_internal: cc 4294967230 || mb 0 || mbcnt 0
KDB: enter: panic
[thread pid 1213 tid 100082 ]
Stopped at      kdb_enter+0x2b: nop
db> where
Tracing pid 1213 tid 100082 td 0xc10e3ae0
kdb_enter(c06b0fd6) at kdb_enter+0x2b
panic(c06b5335,ffffffbe,0,0,c1308580,...) at panic+0xbb
sbflush_internal(c1308580,c8058aa0,c0554f3a,c1308580,c1308530,...) at
sbflush_internal+0x6f
sbflush_locked(c1308580) at sbflush_locked+0xb
sbflush(c1308580,c1308530,c0f9bb28,0,c1308530,...) at sbflush+0x3a
tcp_disconnect(c12ce594) at tcp_disconnect+0x4b
tcp_usr_disconnect(c1308530,c8058af8,c0555e05,c1308530,0,...) at
tcp_usr_disconnect+0x88
sodisconnect(c1308530,0,c124a240,0,0,...) at sodisconnect+0x26
soclose(c1308530) at soclose+0x31
soo_close(c124a240,c10e3ae0) at soo_close+0x5f
fdrop_locked(c124a240,c10e3ae0,c126ca00,c8058ba4,c04f1ebf,...) at
fdrop_locked+0xc8
fdrop(c124a240,c10e3ae0,c0f6bb84,c0966980,0,...) at fdrop+0x3d
closef(c124a240,c10e3ae0) at closef+0x407
fdfree(c10e3ae0) at fdfree+0x56b
exit1(c10e3ae0,0,c8058d2c,c06847f2,c10e3ae0,...) at exit1+0x427
exit1(c10e3ae0,c8058d00) at exit1
syscall(c8058d38) at syscall+0x2a2
Xint0x80_syscall() at Xint0x80_syscall+0x20
- --- syscall (3, FreeBSD ELF32, read), eip = 0x2, esp = 0x292, ebp = 0 ---
db> show socket 0xc1308530
socket at 0xc1308530
  so_count: 1   so_type: 1 (SOCK_STREAM)
  so_options: 0x20c (SO_REUSEADDR, SO_KEEPALIVE, SO_REUSEPORT)
  so_linger: 0   so_state: 0xa (SS_ISCONNECTED, SS_ISDISCONNECTING)
  so_qstate: 0x0 ()   so_pcb: 0xc0f9bb28   so_proto: 0xc06eed68
  so_proto at 0xc06eed68
    pr_type: 1   pr_domain: 0xc06ef180
    pr_domain at 0xc06ef180
      dom_family: 2   dom_name: internet
      dom_init: 0   dom_externalize: 0   dom_dispose: 0
      dom_protosw: 0xc06eed00   dom_next: 0xc06e97c0
      dom_rtattach: 0xc05c2ef0   dom_rtoffset: 32   dom_maxrtkey: 16
      dom_ifattach: 0   dom_ifdetach: 0
    pr_protocol: 6
    pr_flags: 44 (PR_CONNREQUIRED, PR_WANTRCVD, PR_IMPLOPCL)
    pr_input: 0xc05cbd5c   pr_output: 0   pr_ctlinput: 0xc05d1c54
    pr_ctloutput: 0xc05d6380   pr_ousrreq: 0   pr_init: 0xc05d0988
    pr_fasttimo: 0   pr_slowtimo: 0xc05d427c   pr_drain: 0xc05d1360
    pr_ousrreq: 0
  so_head: 0   so_incomp first: 0   so_comp first: 0
  so_qlen: 0   so_incqlen: 0   so_qlimit: 0   so_timeo: 0   so_error: 0
  so_sigio: 0   so_oobmark: 0   so_aiojobq first: 0
  so_rcv at 0xc1308580
    sb_state: 0x20 (SS_CANTRCVMORE)
    sb_mb: 0   sb_mbtail: 0   sb_lastrecord: 0
    sb_cc: -66   sb_hiwat: 66608   sb_mbcnt: 0   sb_mbmax: 262144
    sb_ctl: 0   sb_lowat: 1   sb_timeo: 0
    sb_flags: 0x800 (SB_AUTOSIZE)
  so_snd at 0xc13085ec
    sb_state: 0x10 (SS_CANTSENDMORE)
    sb_mb: 0   sb_mbtail: 0   sb_lastrecord: 0
    sb_cc: 0   sb_hiwat: 66608   sb_mbcnt: 0   sb_mbmax: 262144
    sb_ctl: 0   sb_lowat: 2048   sb_timeo: 0
    sb_flags: 0x800 (SB_AUTOSIZE)

I hope this is useful...

Regards
Florian

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