Re: [PATCH] pinctrl: mediatek: Free eint data on failure

From: Sean Wang
Date: Wed Aug 19 2020 - 20:00:30 EST

On Wed, Aug 19, 2020 at 9:19 AM Enric Balletbo i Serra
<enric.balletbo@xxxxxxxxxxxxx> wrote:
>
> The pinctrl driver can work without the EINT resource, but, if it is
> expected to have this resource but the mtk_build_eint() function fails
> after allocating their data (because can't get the resource or can't map
> the irq), the data is not freed and you end with a NULL pointer
> dereference. Fix this by freeing the data if mtk_build_eint() fails, so
> pinctrl still works and doesn't hang.
>
> This is noticeable after commit f97dbf48ca43 ("irqchip/mtk-sysirq: Convert
> to a platform driver") on MT8183 because, due this commit, the pinctrl driver
> fails to map the irq and spots the following bug:
>
> [ 1.947597] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000004
> [ 1.956404] Mem abort info:
> [ 1.959203] ESR = 0x96000004
> [ 1.962259] EC = 0x25: DABT (current EL), IL = 32 bits
> [ 1.967565] SET = 0, FnV = 0
> [ 1.970613] EA = 0, S1PTW = 0
> [ 1.973747] Data abort info:
> [ 1.976619] ISV = 0, ISS = 0x00000004
> [ 1.980447] CM = 0, WnR = 0
> [ 1.983410] [0000000000000004] user address but active_mm is swapper
> [ 1.989759] Internal error: Oops: 96000004 [#1] PREEMPT SMP
> [ 1.995322] Modules linked in:
> [ 1.998371] CPU: 7 PID: 1 Comm: swapper/0 Not tainted 5.9.0-rc1+ #44
> [ 2.004715] Hardware name: MediaTek krane sku176 board (DT)
> [ 2.010280] pstate: 60000005 (nZCv daif -PAN -UAO BTYPE=--)
> [ 2.015850] pc : mtk_eint_set_debounce+0x48/0x1b8
> [ 2.020546] lr : mtk_eint_set_debounce+0x34/0x1b8
> [ 2.025239] sp : ffff80001008baa0
> [ 2.028544] x29: ffff80001008baa0 x28: ffff0000ff7ff790
> [ 2.033847] x27: ffff0000f9ec34b0 x26: ffff0000f9ec3480
> [ 2.039150] x25: ffff0000fa576410 x24: ffff0000fa502800
> [ 2.044453] x23: 0000000000001388 x22: ffff0000fa635f80
> [ 2.049755] x21: 0000000000000008 x20: 0000000000000000
> [ 2.055058] x19: 0000000000000071 x18: 0000000000000001
> [ 2.060360] x17: 0000000000000000 x16: 0000000000000000
> [ 2.065662] x15: ffff0000facc8470 x14: ffffffffffffffff
> [ 2.070965] x13: 0000000000000001 x12: 00000000000000c0
> [ 2.076267] x11: 0000000000000040 x10: 0000000000000070
> [ 2.081569] x9 : ffffaec0063d24d8 x8 : ffff0000fa800270
> [ 2.086872] x7 : 0000000000000000 x6 : 0000000000000011
> [ 2.092174] x5 : ffff0000fa800248 x4 : ffff0000fa800270
> [ 2.097476] x3 : ffff8000100c5000 x2 : 0000000000000000
> [ 2.102778] x1 : 0000000000000000 x0 : 0000000000000000
> [ 2.108081] Call trace:
> [ 2.110520] mtk_eint_set_debounce+0x48/0x1b8
> [ 2.114870] mtk_gpio_set_config+0x5c/0x78
> [ 2.118958] gpiod_set_config+0x5c/0x78
> [ 2.122786] gpiod_set_debounce+0x18/0x28
> [ 2.126789] gpio_keys_probe+0x50c/0x910
> [ 2.130705] platform_drv_probe+0x54/0xa8
> [ 2.134705] really_probe+0xe4/0x3b0
> [ 2.138271] driver_probe_device+0x58/0xb8
> [ 2.142358] device_driver_attach+0x74/0x80
> [ 2.146532] __driver_attach+0x58/0xe0
> [ 2.150274] bus_for_each_dev+0x70/0xc0
> [ 2.154100] driver_attach+0x24/0x30
> [ 2.157666] bus_add_driver+0x14c/0x1f0
> [ 2.161493] driver_register+0x64/0x120
> [ 2.165319] __platform_driver_register+0x48/0x58
> [ 2.170017] gpio_keys_init+0x1c/0x28
> [ 2.173672] do_one_initcall+0x54/0x1b4
> [ 2.177499] kernel_init_freeable+0x1d0/0x238
> [ 2.181848] kernel_init+0x14/0x118
> [ 2.185328] ret_from_fork+0x10/0x34
> [ 2.188899] Code: a9438ac1 12001266 f94006c3 121e766a (b9400421)
> [ 2.194991] ---[ end trace 168cf7b3324b6570 ]---
> [ 2.199611] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
> [ 2.207260] SMP: stopping secondary CPUs
> [ 2.211294] Kernel Offset: 0x2ebff4800000 from 0xffff800010000000
> [ 2.217377] PHYS_OFFSET: 0xffffb50500000000
> [ 2.221551] CPU features: 0x0240002,2188200c
> [ 2.225811] Memory Limit: none
> [ 2.228860] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b ]---
>
> Fixes: 89132dd8ffd2 ("pinctrl: mediatek: extend eint build to pinctrl-mtk-common-v2.c")
> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx>
> ---
>
> .../pinctrl/mediatek/pinctrl-mtk-common-v2.c | 27 ++++++++++++++-----
> 1 file changed, 20 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c b/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c
> index 2f3dfb56c3fa..4b532e6b9038 100644
> --- a/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c
> +++ b/drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c
> @@ -355,6 +355,7 @@ int mtk_build_eint(struct mtk_pinctrl *hw, struct platform_device *pdev)
> {
> struct device_node *np = pdev->dev.of_node;
> struct resource *res;
> + int ret;
>
> if (!IS_ENABLED(CONFIG_EINT_MTK))
> return 0;
> @@ -369,19 +370,26 @@ int mtk_build_eint(struct mtk_pinctrl *hw, struct platform_device *pdev)
> res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "eint");
> if (!res) {
> dev_err(&pdev->dev, "Unable to get eint resource\n");
> - return -ENODEV;
> + ret = -ENODEV;
> + goto err_free_eint;
> }
>
> hw->eint->base = devm_ioremap_resource(&pdev->dev, res);
> - if (IS_ERR(hw->eint->base))
> - return PTR_ERR(hw->eint->base);
> + if (IS_ERR(hw->eint->base)) {
> + ret = PTR_ERR(hw->eint->base);
> + goto err_free_eint;
> + }
>
> hw->eint->irq = irq_of_parse_and_map(np, 0);
> - if (!hw->eint->irq)
> - return -EINVAL;
> + if (!hw->eint->irq) {
> + ret = -EINVAL;
> + goto err_free_eint;
> + }
>
> - if (!hw->soc->eint_hw)
> - return -ENODEV;
> + if (!hw->soc->eint_hw) {
> + ret = -ENODEV;
> + goto err_free_eint;
> + }
>
> hw->eint->dev = &pdev->dev;
> hw->eint->hw = hw->soc->eint_hw;
> @@ -389,6 +397,11 @@ int mtk_build_eint(struct mtk_pinctrl *hw, struct platform_device *pdev)
> hw->eint->gpio_xlate = &mtk_eint_xt;
>
> return mtk_eint_do_init(hw->eint);
> +

Similarly, I think we have to call devm_ioremap_release to explicitly
free resource when a certain failure occurs after
devm_ioremap_resource, right?

> +err_free_eint:
> + devm_kfree(hw->dev, hw->eint);
> + hw->eint = NULL;
> + return ret;
> }
> EXPORT_SYMBOL_GPL(mtk_build_eint);
>
> --
> 2.28.0
>