Re: XFS/md/blkdev warning (was Re: Linux 2.6.26-rc2)

[Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>]

On Sat, 17 May 2008, Linus Torvalds wrote:
> 
> Do this on the console (and having a serial console or working netconsole 
> is a wonderful thing to log it, because otherwise it will generally just 
> scroll off the screen), and trigger SysRQ-w. That dumps all blocked tasks 
> to the screen.

Another thing to try is to enable lock debugging, and have

        CONFIG_DEBUG_SPINLOCK=y
        CONFIG_DEBUG_MUTEXES=y
        CONFIG_DEBUG_LOCK_ALLOC=y
        CONFIG_PROVE_LOCKING=y
        CONFIG_LOCKDEP=y
        CONFIG_DEBUG_LOCKDEP=y

in your kernel .config file. It has performance implications, of course, 
but it can help debug incorrect locking much more quickly.

                Linus