amd64/129488: Kernel "bug" when using smbfs in smbfs_smb.c: kernel: bug: ecnt = 1, but m_len = 0 and m_next = 0

[Eric Sabban]

>Number:         129488
>Category:       amd64
>Synopsis:       Kernel "bug" when using smbfs in smbfs_smb.c: kernel: bug: ecnt = 1, but m_len = 0 and m_next = 0
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-amd64
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sun Dec 07 22:30:00 UTC 2008
>Closed-Date:
>Last-Modified:
>Originator:     Eric Sabban
>Release:        7.0-RELEASE-p7
>Organization:
none
>Environment:
FreeBSD sekret.lame.net 7.0-RELEASE-p6 FreeBSD 7.0-RELEASE-p6 #3: Thu Dec  4 21:48:54 PST 2008     root at sekret.lame.net:/usr/obj/usr/src/sys/SEKRET  amd64

>Description:
Shortly after booting the fileserver (leopard g5) and the smb client (freebsd 7.0p6) I mounted two disks over smb (mount //eric at g5/blah)  from the server. I did an awful thing, just for the sake of it:

for i in *.avi; do file=`echo ${i} | sed -e 's/.avi$//'`; ffmpeg -i "${file}.avi" "/usr/tmp/${file}.mp4" > /tmp/ffmpeg.$$ 2>&1 & done

Ugly as that may have been, the kernel then spit out:

smb_iod_recvall: drop resp with mid 4526
smb_iod_recvall: drop resp with mid 4527
smb_iod_recvall: drop resp with mid 4528
smb_iod_recvall: drop resp with mid 4530
smb_iod_recvall: drop resp with mid 4531
bug: ecnt = 1, but m_len = 0 and m_next = 0 (please report)

Nothing really HAPPENED, but you asked me to report, so here I am.

>How-To-Repeat:
Start out a bunch of concurrent I/O from a fileserver that likely cannot handle it, I did it shortly after booting both the fileserver and the client.
>Fix:
If only I knew.


>Release-Note:
>Audit-Trail:
>Unformatted: