Re: [heads-up] deadlock in configfs_symlink()

Re: [heads-up] deadlock in configfs_symlink()

[Felipe Balbi]

Hi,

On Sun, Aug 4, 2019 at 11:48 PM Al Viro <viro@zeniv.linux.org.uk> wrote:
>
> On Sun, Aug 04, 2019 at 09:31:43PM +0100, Al Viro wrote:
>
> > FWIW, the following reproduces the deadlock on mainline:
> >
> > dd if=/dev/zero of=/tmp/image bs=1M count=20
> > modprobe dummy_hcd
> > modprobe configfs
> > mount -t configfs none /sys/kernel/config
> > modprobe g_mass_storage file=/tmp/image ro=y
> > cd /sys/kernel/config/usb_gadget/
> > mkdir blah
> > cd blah/configs
> > mkdir foo.1
> > cd foo.1
> > ln -s /sys/kernel/config/usb_gadget/blah/configs/foo.1/no-such-dir/ barf
>
> So does the following, actually - mass_storage is irrelevant here; it just
> brings libcomposite in.
>
> modprobe dummy_hcd
> modprobe libcomposite
> mount -t configfs none /sys/kernel/config
> cd /sys/kernel/config/usb_gadget/
> mkdir blah
> cd blah/configs
> mkdir foo.1
> cd foo.1
> ln -s /sys/kernel/config/usb_gadget/blah/configs/foo.1/no-such-dir/ barf

I'll try to reproduce on my end. Added linux-usb to the loop

-- 
balbi