mtd: unable to unregister device

[Fabio Estevam]

Hi,

Running top of head linus tree or linux-next I observe the following issue:

fsl-quadspi is autloaded as a kernel module:

[    9.670508] fsl-quadspi 21e4000.qspi: s25fl128s (16384 Kbytes)
[    9.763432] fsl-quadspi 21e4000.qspi: s25fl128s (16384 Kbytes)
[    9.847063] fsl-quadspi 21e4000.qspi: QuadSPI SPI NOR flash driver

root at freescale /$ cat /proc/mtd
dev:    size   erasesize  name
mtd0: 01000000 00010000 "21e4000.qspi"
mtd1: 01000000 00010000 "21e4000.qspi"

root at freescale /$ rmmod  fsl-quadspi
root at freescale /$ cat /proc/mtd
dev:    size   erasesize  name
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: 00000000 00000000 "(null)"
mtd0: a22296c6c756e28 00000000 "(null)"
mtd0: a22296c6c756e28 3064746d "(null)"

Because of this failed unregistration, If I continue with the
load/unload sequence, then kernel will crash.

I don't think this issue is related to
drivers/mtd/spi-nor/fsl-quadspi.c itself, as the same driver can
load/unload correctly on a FSL 3.10 kernel.

Any ideas? Thanks