[BUG] mtd: rawnand: denali_pci: page fault when probing fails

[Zheyu Ma]

Hello,

I found a bug in the denali_pci module.
When the driver fails to probe, we will get the following splat:

[    4.472703] denali-nand-pci 0000:00:05.0: timeout while waiting for
irq 0x1000
[    4.474071] denali-nand-pci: probe of 0000:00:05.0 failed with error -5
[    4.473538] nand: No NAND device found
[    4.474068] BUG: unable to handle page fault for address:
ffffc90005000410
[    4.475169] #PF: supervisor write access in kernel mode
[    4.475579] #PF: error_code(0x0002) - not-present page
[    4.478362] RIP: 0010:iowrite32+0x9/0x50
[    4.486068] Call Trace:
[    4.486269]  <IRQ>
[    4.486443]  denali_isr+0x15b/0x300 [denali]
[    4.486788]  ? denali_direct_write+0x50/0x50 [denali]
[    4.487189]  __handle_irq_event_percpu+0x161/0x3b0
[    4.487571]  handle_irq_event+0x7d/0x1b0
[    4.487884]  handle_fasteoi_irq+0x2b0/0x770
[    4.488219]  __common_interrupt+0xc8/0x1b0
[    4.488549]  common_interrupt+0x9a/0xc0

It seems that the driver unmap the memory region before disabling the irq.

Regards,
Zheyu Ma