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

[Zheyu Ma]

On Mon, Apr 11, 2022 at 3:37 PM Miquel Raynal <miquel.raynal@xxxxxxxxxxx> wrote:
>
> Hi Zheyu,
>
> zheyuma97@xxxxxxxxx wrote on Sun, 10 Apr 2022 22:17:35 +0800:
>
> > 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.
>
> Thanks for the report! The mapping is done with devm_ helpers and so is
> the IRQ registration, so it's slightly more complicated that just
> moving a function call in the remove path, apparently. Would you mind
> investigating and proposing a patch?

I have proposed a patch for this issue, please correct me if I am wrong.

Thanks,
Zheyu Ma