Re: [RFT v2] pinctrl: samsung: Fix NULL pointer exception on external interrupts on S3C24xx

From: Lihua Yao
Date: Fri Jun 16 2017 - 13:01:16 EST

On Thursday, June 15, 2017 11:46 PM, Krzysztof Kozlowski wrote:
After commit 8b1bd11c1f8f ("pinctrl: samsung: Add the support the
multiple IORESOURCE_MEM for one pin-bank"), the S3C24xx (and probably
S3C64xx as well) fails:

Unable to handle kernel NULL pointer dereference at virtual address 000000a8
(s3c24xx_demux_eint4_7) from [<c004469c>] (__handle_domain_irq+0x6c/0xcc)
(__handle_domain_irq) from [<c0009444>] (s3c24xx_handle_irq+0x6c/0x12c)
(s3c24xx_handle_irq) from [<c000e5fc>] (__irq_svc+0x5c/0x78)

Mentioned commit moved the pointer to controller's base IO memory address
from each controller's driver data (samsung_pinctrl_drv_data) to per-bank
structure (samsung_pin_bank). The external interrupt demux
handlers (s3c24xx_demux_eint()) tried to get this base address from opaque
pointer stored under irq_chip data:

struct irq_data *irqd = irq_desc_get_irq_data(desc);
struct samsung_pin_bank *bank = irq_data_get_irq_chip_data(irqd);
pend = readl(bank->eint_base + EINTPEND_REG);

which is wrong because this is hardware irq and it bank was never set
for this irq_chip.

For S3C24xx and S3C64xx, this partially reverts mentioned commit by
bringing back the virt_base stored under each controller's driver data
(samsung_pinctrl_drv_data). This virt_base address will be now
- samsung_pinctrl_drv_data->virt_base: used on S3C24xx and S3C64xx,
- samsung_pin_bank->pctl_base: used on Exynos.

Fixes: 8b1bd11c1f8f ("pinctrl: samsung: Add the support the multiple IORESOURCE_MEM for one pin-bank")
Cc: <stable@xxxxxxxxxxxxxxx>
Cc: Sergio Prado <sergio.prado@xxxxxxxxxxxxxx>
Reported-by: Sergio Prado <sergio.prado@xxxxxxxxxxxxxx>
Signed-off-by: Krzysztof Kozlowski <krzk@xxxxxxxxxx>


Tested on Odroid XU3.
Please kindly test on S3C24xx and S3C64xx. Other tests, including
Exynos5433 are also welcomed.

Changes since v1:
1. Fix NULL pointer exception when setting virt_base because bdata
pointer is invalid at this point (incremented by loop). Spotted
by Yao Lihua.
Works well for me. Tested on TINY6410 board.

Tested-by: Lihua Yao <ylhuajnu@xxxxxxx>