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Date: Thu, 27 Jul 1995 10:30:09 -0700
From: Matt Dillon <dillon@blob.best.net>
Message-Id: <199507271730.KAA27241@blob.best.net>
To: bugs@freebsd.org
Subject: More on our shell2 crashes
Sender: bugs-owner@freebsd.org
Precedence: bulk

    This time around it crashed with a panic("nfsreq nogrps")

    I am also seeing this:

Jul 27 08:40:31 shell2 /kernel: vnode_pager_getpages: I/O read error
Jul 27 08:40:32 shell2 /kernel: vm_fault: pager input (probably hardware) error,
 PID 690 failure
Jul 27 08:40:32 shell2 /kernel: vnode_pager_getpages: I/O read error
Jul 27 08:40:32 shell2 /kernel: vm_fault: pager input (probably hardware) error,
 PID 690 failure
Jul 27 08:40:32 shell2 /kernel: vnode_pager_getpages: I/O read error
Jul 27 08:40:32 shell2 /kernel: vm_fault: pager input (probably hardware) error,
 PID 690 failure
Jul 27 08:40:32 shell2 /kernel: vnode_pager_getpages: I/O read error
Jul 27 08:40:32 shell2 /kernel: vm_fault: pager input (probably hardware) error,
 PID 690 failure
Jul 27 08:40:32 shell2 /kernel: pid 690: ftpd: uid 1905: exited on signal 6
Jul 27 08:40:29 shell2 ftpd[690]: exiting on signal 11
Jul 27 08:41:08 shell2 login: login from Sun.COM as durrell
Jul 27 08:50:28 shell2 login: login from war.ts.best.com as pgildea
Jul 27 08:52:50 shell2 login: login from shell2 as webmastr

    This type of thing is occuring a whole lot... every couple of hours.
    It always seems to be coming from FTPD.

    The ftpd executable in this case is *ON* an NFS partition.  While the
    messages are not really verbose enough, I believe the failure is occuring
    when shell2 tries to page in some pages from the ftpd executable over NFS.

    Another thing of interest: ftpd is modes 550 root.wheel, meaning that a 
    screwup in the ucred *could* be causing the read failure.  Thus there
    could be a relationship with the panic and the vnode_pager_getpages
    fazilures if ucred is somehow getting corrupted or it's reference count
    is getting messed up.

    I do not see a correlation with the bio_done page_busy < 0 problem so far.

    --

    For the time being, I have moved the ftpd executable to local disk and will
    observe if the pager errors still occur.

						-Matt