On Wed, 17 Feb 2021 20:10:50 +0000,
Michael Walle <mich...@walle.cc> wrote:
>
> Am 2021-02-17 21:02, schrieb Marc Zyngier:
> > On 2021-02-17 19:57, Michael Walle wrote:
> >> Hi Greg,
> >>
> >>> There's no need to keep around a dentry pointer to a simple file that
> >>> debugfs itself can look up when we need to remove it from the system.
> >>> So simplify the code by deleting the variable and cleaning up the
> >>> logic
> >>> around the debugfs file.
> >>
> >> This will generate the following oops on my board (arm64,
> >> freescale/fsl-ls1028a-kontron-sl28-var3-ads2.dts). In debugfs_lookup()
> >> debugfs_mount is NULL.
> >
> > That's odd. I gave it a go yesterday, and nothing blew up.
> > Which makes me wonder whether I had the debug stuff enabled
> > the first place...
> >
> > I've dropped the patch from -next for now until I figure it out
> > (probably tomorrow).
>
> Mh, maybe its my .config, I've attached it. I also noticed that
> the board boots just fine in our kernel-ci [1].
I reproduced here. I had disabled GENERIC_IRQ_DEBUGFS for obscure
reasons, and it caught fire as I re-enabled it.
Adding this fixes it for me:
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index 367ff1c35f75..d8a14cf1a7b6 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -1904,7 +1904,8 @@ static void debugfs_add_domain_dir(struct irq_domain *d)
static void debugfs_remove_domain_dir(struct irq_domain *d)
{
- debugfs_remove(debugfs_lookup(d->name, domain_dir));
+ if (domain_dir)
+ debugfs_remove(debugfs_lookup(d->name, domain_dir));
}
void __init irq_domain_debugfs_init(struct dentry *root)
Could you please check whether it works for you?
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
