Re: Analyzed/Solved/Bisected: Booting 2.6.30-rc2-git7 very slow

Kay Sievers
2009-05-27T20:57:20Z

On Wed, May 27, 2009 at 22:31, Andrew Morton <akpm@linux-foundation.org> wrote:
> On Wed, 27 May 2009 04:25:57 -0700 (PDT)
> Martin Knoblauch <knobi@knobisoft.de> wrote:
>
>>  FWIW, I compiled the CCISS driver into the kernel. This makes the second "/sys" line in /proc/mounts go away, dmesg attached. But does it prove anything? The initialization of the CCISS hardware now happens about 2 seconds earlier in the bootup sequence. Does this hint to a problem with CCISS, or just confirms that the whole issue is really timing dependent? Anyway, I add Mike to CC.
>>
>
> It seems that the PCI change caused timing changes which triggered a
> udev/sysfs/whatever problem, which manifests as the duplicated
> /proc/mounts entry to turn up.
>
> What we don't know (afaik) is why the kernel permitted two entries in
> /proc/mounts.  That might be a bug.
>
> It could be that if dual /proc/mounts problem gets fixed, everything
> works OK - by intent or by accident, the userspace startup scripts may
> then work acceptably.
>
> I think Al asked you a few questions around the behaviour of mount(8)
> and the mount syscall, so we could delve further into why /proc/mounts
> is getting mucked up.  Did you end up running those tests?

I expect the duplicate comes from a left-over mount in initramfs which
isn't a duplicate in the sense of a bug in vfs or mount or anything. I
guess, it is just still mounted in the initial kernel rootfs, below
the root from the disk. It could be that a umount from initramfs did
go wrong because of a changed timing.

Thanks,
Kay