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