Re: [PATCH] irqdomain: remove debugfs_file from struct irq_domain

Greg KH
2021-02-18T09:59:16Z

On Wed, Feb 17, 2021 at 08:57:17PM +0100, 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.
>
> [ 0.000000] Linux version 5.11.0-next-20210217-00014-g41e0e92a2d05 (mwalle@mwalle01) (aarch64-linux-gnu-gcc (Debian 8.3.0-2) 8.3.0, GNU ld (GNU Binutils for Debian) 2.31.1) #69 SMP PREEMPT Wed Feb 17 20:47:10 CET 2021
> [..]
> [ 0.000000] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
> [ 0.000000] Mem abort info:
> [ 0.000000] ESR = 0x96000004

<snip>

Back to this log, do you see:
"Unable to pin filesystem for file "
anywhere before this crash?

thanks,

greg k-h