[arch-projects] [PATCH 4/7] udev: exit on shutdown

[Dave Reisner]

On Wed, Oct 26, 2011 at 07:12:13PM -0500, Dan McGee wrote:
> On Wed, Oct 26, 2011 at 6:38 PM, Tom Gundersen <teg at jklm.no> wrote:
> > udev was receiving some events (due to e.g. swapoff) on shutdown
> > that caused it to fork new processes. These then receivde TERM before
> s/received/
> > they could finish, and complained on the console.
> >
> > In principle, I'm worried that, with the right ammonut of bad luck,
> s/amount/
> > we could fork off some process at exactly the wrong time which escapes
> > the killall logic.
> >
> > This, by the way, highlights the frailty of the killall stuff.
> Two quick thoughts here
> 1. Is there a need to even call swapoff? I can't believe it is
> essential for swap partitions. It unfortunately does makes sense for
> swap files so we can later unmount the file system they live on, but
> it looks like there is no way to differentiate. Dave, I know you want
> to submit a patch to util-linux for this... :)

I'm such a tool. Preliminary patchwork for this now exists:

http://code.falconindy.com/cgit/util-linux.git/log/?h=swapon

If anyone wants to give it a once over from a user or developer
perspective, that'd be awesome.

d

> 2. Why do we do anything except unmounting filesystems after the
> kill_all call? It seems like we could move the random seed, and
> timezone set above it, and then kill udev, and then we'd be safe from
> any and all spawned processes.
> The only things following would be (hooks excluded) a umount call,
> vgchange/cryptsetup calls, a mount call, and either poweroff/reboot.
> That seems pretty easy to audit, and I feel like you took a potshot at
> the killall thing when in fact udevd was the only bad boy in the
> corner causing trouble.
> 
> >
> > Signed-off-by: Tom Gundersen <teg at jklm.no>
> > ---
> >  rc.shutdown |    2 ++
> >  1 files changed, 2 insertions(+), 0 deletions(-)
> >
> > diff --git a/rc.shutdown b/rc.shutdown
> > index 8363737..5928b2d 100755
> > --- a/rc.shutdown
> > +++ b/rc.shutdown
> > @@ -19,6 +19,8 @@ run_hook shutdown_start
> >
> >  stop_all_daemons
> >
> > +status "Shutting down UDev" udevadm control --exit
> > +
> >  status "Deactivating Swap" swapoff -a
> >
> >  # stop monitoring of lvm2 groups before unmounting filesystems
> > --
> > 1.7.7.1
> >
> >