misc/167362: Reproduceble Page Fault when running rsync over sshfs/encfs.

[Eric Crews]

>Number:         167362
>Category:       misc
>Synopsis:       Reproduceble Page Fault when running rsync over sshfs/encfs.
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Fri Apr 27 15:00:24 UTC 2012
>Closed-Date:
>Last-Modified:
>Originator:     Eric Crews
>Release:        9.0-RELEASE
>Organization:
>Environment:
FreeBSD 9.0-RELEASE FreeBSD 9.0-RELEASE #0: Tue Jan 3 07:46:30 UTC 2012
root at farrell.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC amd64
>Description:
I mount a directory from a remote server via sshfs to my zpool partition.  Next I open an encrypted container in the sshfs mounted directory with encfs. Finally, when I attempt to rsync data into the unencrypted encfs mounted container the system immediately throws a Page Fault and totally freezes up.  Even the core dump fails to complete.  This is all the information( from the terminal screen ) of the fault I have.

****************************************************
Fatal trap 12: page fault while in kernel mode
cpuid = 1; apic id = 01
fault virtual address     = 0x0
fault code                = supervisor read instruction, page not present
instruction pointer       = 0x20 :0x0
stack pointer             = 0x28 :0xffffff80559cdad0
frame pointer             = 0x28 :0xffffff80559cdb20
code segment              = base 0x0, limit 0xffffff, type 0x1b
                          = DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags          = interrupt enabled, resume, IOPL = 0
current process           = 1632 (rsync)
trap number               = 12
panic: page fault
cupid = 1
KDB: stack backtrace:
#0 0xffffffff808680fe at kdb_backtrace+0x5e
#1 0xffffffff80832cb7 at panic+0x187
#2 0xffffffff80b18400 at trap_fatal+0x290
#3 0xffffffff80b18749 at trap_pfault+0x1f9
#4 0xffffffff80b18c0f at trap+0x3df
#5 0xffffffff80b0313f at calltrap+0x8
#6 0xffffffff80b17cf0 at amd64_syscall+0x450
#7 0xffffffff80b03427 at Zfast_syscall+0xf7 
**********************************************************

I have tried this on both a zpool and a zpool on top of geli containers and gotten the same page fault every time.

I have previously done this same procedure on Ubuntu and Gentoo servers with no problems.
>How-To-Repeat:
sshfs <user>@<remote Server>:/home/<user> /mnt/archive

encfs -S /mnt/archive/.crypt /archive

rsync -avzqrpogtu /stuff /archive
>Fix:


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