Subject: Re: unable to dump kernel core
To: Antti Kantee <>
From: David Holland <>
List: tech-kern
Date: 11/05/2007 21:21:51
On Sun, Nov 04, 2007 at 10:26:13PM +0200, Antti Kantee wrote:
 > For some time now I've been unable to get a kernel coredump from a system.
 > At first I thought the system merely hung without panicking, but recently
 > I discovered that it was in fact either "syncing disks" or "dumping to .."
 > which made the system hang (this was fairly difficult to see from X).
 > I tried it in qemu also with the same result.  It seems that the I/O
 > for reading the swap device disklable never finishes and it is waited
 > for indefinitely:

Is it deadlocked?

IME, after a FS-related panic, "syncing disks" usually deadlocks, or
at least it seems to.

I wonder if it would be worth writing a general-purpose deadlock
detector and turning it on when LOCKDEBUG is set...

   - David A. Holland /