linux-kernel - Re: linux-next: Tree for Jul 4

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Date:   Sat, 6 Jul 2019 17:42:24 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Stephen Rothwell <sfr@...b.auug.org.au>
Cc:     Linux Next Mailing List <linux-next@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Michael Ellerman <mpe@...erman.id.au>
Subject: Re: linux-next: Tree for Jul 4

On Sat, Jul 06, 2019 at 08:17:29PM +1000, Stephen Rothwell wrote:
> Hi Greg,
> 
> On Sat, 6 Jul 2019 11:46:47 +0200 Greg Kroah-Hartman <gregkh@...uxfoundation.org> wrote:
> >
> > On Sat, Jul 06, 2019 at 07:44:12PM +1000, Stephen Rothwell wrote:
> > > 
> > > On Sat, 6 Jul 2019 10:34:33 +0200 Greg Kroah-Hartman <gregkh@...uxfoundation.org> wrote:  
> > > >
> > > > On Thu, Jul 04, 2019 at 10:24:50PM +1000, Stephen Rothwell wrote:  
> > > > > 
> > > > > This release produces a whole lot (over 200) of this message in my qemu
> > > > > boot tests:
> > > > > 
> > > > > [    1.698497] debugfs: File 'sched' already present!
> > > > > 
> > > > > Introduced by commit
> > > > > 
> > > > >   43e23b6c0b01 ("debugfs: log errors when something goes wrong")
> > > > > 
> > > > > from the driver-core tree.  I assume that the error(?) was already
> > > > > happening, but it is now being reported.    
> > > > 
> > > > What are you passing to qemu to get this?  I just tried it myself and
> > > > see no error reports at all.  Have a .config I can use to try to
> > > > reproduce this?  
> > > 
> > > It is a powerpc pseries_le_defconfig kernel and I run qemu like this:
> > > 
> > > qemu-system-ppc64 -M pseries -m 2G -vga none -nographic -kernel vmlinux -initrd rootfs.cpio.gz  
> > 
> > Hm, I think my rootfs initrd might be quite simple compared to yours (it
> > drops me into a busybox shell).  Any pointers to where you created yours
> > from?
> 
> Michael Ellerman gave it to me.  It is very simple.  Its /init is just
> 
> $ cat init
> #!/bin/sh
> # devtmpfs does not get automounted for initramfs
> /bin/mount -t devtmpfs devtmpfs /dev
> exec 0</dev/console
> exec 1>/dev/console
> exec 2>/dev/console
> exec /sbin/init $*
> 
> and /sbin/init is a link to /bin/busybox
> 
> It is all run by an expect script that just waits for the login:
> prompt, logs in a root and runs "halt".
> 
> All the debugfs messages appear before the kernel finished booting.

Ah, found the bug.  Turns out I caused it in the blk queue debugfs code
a short while ago.  I'll post a patch for this in a few minutes...

thanks,

greg k-h