panic: userret: Returning with 1 locks held.

[Danny Braniss]

> with the latest kernel, the message changed somewhat, but the panic is
> still there (this is an amd64):
> 
> trap 12: page fault while in kernel mode
> cpuid = 1; apic id = 01
> fault virtual address   = 0x0
> fault code              = supervisor read, page not present
> instruction pointer     = 0x8:0xffffffff8038e3f5
> stack pointer           = 0x10:0xffffffffb280e7b0
> frame pointer           = 0x10:0xffffffffb280e7e0
> code segment            = base 0x0, limit 0xfffff, type 0x1b
>                         = DPL 0, pres 1, long 1, def32 0, gran 1
> processor eflags        = interrupt enabled, resume, IOPL = 0
> current process         = 241 (sh)
> [thread pid 241 tid 100071 ]
> Stopped at      _mtx_lock_flags+0x35:   cmpq    $0x80779d40,0(%rdi)
> db> tr
> Tracing pid 241 tid 100071 td 0xffffff007ae25980
> _mtx_lock_flags() at _mtx_lock_flags+0x35
> exec_map_first_page() at exec_map_first_page+0x60
> kern_execve() at kern_execve+0x2a0
> execve() at execve+0x5d
> syscall() at syscall+0x4ab
> Xfast_syscall() at Xfast_syscall+0xa8
> --- syscall (59, FreeBSD ELF64, execve), rip = 0x80090630c, rsp = 
> 0x7fffffffcbf8, rbp = 0 ---
> db> show lockedvnods
> Locked vnodes
> 
> 0xffffff0061a48000: tag union, type VREG
>     usecount 1, writecount 0, refcount 1 mountedhere 0
>     flags (VV_TEXT)
>      lock type union: EXCL (count 1) by thread 0xffffff007ae25980 (pid 241)
>         vp=0xffffff0061a48000, uppervp=0, lowervp=0xffffff00626187e0
> union: lower
> 0xffffff00626187e0: tag nfs, type VREG
>     usecount 1, writecount 0, refcount 3 mountedhere 0
>     flags ()
>     v_object 0xffffff007c3a87e0 ref 0 pages 1
>     
>         fileid 47269 fsid 0x900ff01
> db> tr 241
> Tracing pid 241 tid 100071 td 0xffffff007ae25980
> _mtx_lock_flags() at _mtx_lock_flags+0x35
> exec_map_first_page() at exec_map_first_page+0x60
> kern_execve() at kern_execve+0x2a0
> execve() at execve+0x5d
> syscall() at syscall+0x4ab
> Xfast_syscall() at Xfast_syscall+0xa8
> --- syscall (59, FreeBSD ELF64, execve), rip = 0x80090630c, rsp = 
> 0x7fffffffcbf8, rbp = 0 ---
> db> 
> 

the problem is in the unionfs, not loading the module gets me
to the shell's prompt, im now trying i386 ...

danny