Date: Thu, 3 Oct 1996 11:09:13 +0100 (BST) From: Doug Rabson <dfr@render.com> To: Julian Elischer <julian@freefall.freebsd.org> Cc: current@freefall.freebsd.org Subject: Re: HELP!! kernel deadlock found.. Message-ID: <Pine.BSF.3.95.961003105257.10204P-100000@minnow.render.com> In-Reply-To: <199610030539.WAA02269@freefall.freebsd.org>
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On Wed, 2 Oct 1996, Julian Elischer wrote: > > Take the following 3 processes: > > proc N, with a lock on file / (inode 2) > wchan of that inode, waitstring of "ufslk2" > is waiting for inode for /mnt in the root filesystem (inode M) > > proc N+1 with a lock on the inode M (/mnt in root filesystem) > is waiting for inode for / (inode 2) in the mounted filesystem /mnt > it is showing "uihget" as a waitstring. > > proc N+2 with a lock on inode 2 of the mnt filesystem (/ of that filesystem) > is waiting for the inode for / and is showing "ufslk2" as a waitstring. > > It is my suspicion that process N+2 may be trying to unmount /mnt. It looks as if N+2 is attempting to perform a pathname lookup while it has a locked vnode. > > Unfortunatly though I have the system stopped in gdb > I don't know how to examine the stacktrace of arbitrary > processes so I can't say how those 3 processes got where > they are. All other processes on the system > that need to access the filesystem are locked in "ufslk2" > > e.g. any new logins go there immediatly. :( > > if anyone knows how to examine an arbitrary process stacktrace > I'd like to hear about it....... I wanted to do this with DDB once and I think I was stumped by the kernel stack being in the u-area which is mapped to the same place for each process. Since the process I wanted to backtrace was not curproc, I couldn't see its stack :-(. -- Doug Rabson, Microsoft RenderMorphics Ltd. Mail: dfr@render.com Phone: +44 171 734 3761 FAX: +44 171 734 6426
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