kern/40672: wapbl-related diagnostic assert

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>Number:         40672
>Category:       kern
>Synopsis:       wapbl-related diagnostic assert
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Feb 17 13:45:01 +0000 2009
>Originator:     Alan Barrett
>Release:        NetBSD 5.99.7
>Organization:
Not much
>Environment:
System: NetBSD 5.99.7 i386
>Description:
        A DIAGNOSTIC+DEBUG kernel panics in wapbl_add_buf

>How-To-Repeat:
        I have a non-MODULAR i386 kernel with options DEBUG and options
        DIAGNOSTIC.

        On boot, shortly after beginning to run /etc/rc, it panics with

        panic: kernel diagnostic assertion "rw_write_held(&wl->wl_rwlock)"
        failed: file ".../kern/vfs_wapbl.c", line 1556

        According to ddb's bt command, the call chain was:

        __kernassert
        wapbl_jlock_assert
        wapbl_add_buf
        bdwrite
        bwrite
        VOP_BWRITE
        ffs_full_fsync
        ffs_fsync
        VOP_FSYNC
        ...

        The file system is probably nullfs on ffs+wapbl.

>Fix:
        Unknown