kern/132551: ZFS locks up on extattr_list_link syscall

[Tim Kientzle]

>Number:         132551
>Category:       kern
>Synopsis:       ZFS locks up on extattr_list_link syscall
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Wed Mar 11 17:20:06 UTC 2009
>Closed-Date:
>Last-Modified:
>Originator:     Tim Kientzle
>Release:        -CURRENT
>Organization:
>Environment:
>Description:
See bin/132452 for the initial reports of this.

I added extended attribute support to tar recently and
several people reported that making an extattr_list_link
syscall on a ZFS volume hangs the CPU (100% system time)
and results in an unkillable process.  This has been
reported on both amd64 and i386 architectures with recent
-CURRENT.

I don't have a machine with ZFS handy to try to reproduce
this myself; I don't know if this affects 7-STABLE; I don't
know if it also occurs for extattr_list_file or other extattr
system calls.  I'm eager to get this fixed so I can turn
tar's extended attribute support back on.


>How-To-Repeat:
touch foo
lsextattr -h user foo

>Fix:


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