Re: [PATCH v2] spi: imx: fix use-after-free during driver removal

[Frank Li <Frank.li@xxxxxxx>]

On Thu, Aug 08, 2024 at 05:52:23PM +0200, Kirill Yatsenko wrote:
> With the CONFIG_SLUB_DEBUG_ON enabled the unhandled fault error appears
> when unbinding the driver.
>
> The spi controller driver memory is freed inside the spi_imx_remove prior
> to executing PM callbacks thus leading to use-after-free.
>
> Fix it by switching to the devm version of spi_register_controller.
>
> Unhandled fault: alignment exception (0x001) at 0x6b6b6c53
> [6b6b6c53] *pgd=00000000
> Internal error: : 1 [#1] PREEMPT SMP ARM
> Modules linked in:
> CPU: 2 PID: 1241 Comm: rebind.sh Not tainted 6.10.0-dnm3pv2-dnm3pv2-ga03695deba11 #1
> Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
> PC is at __pm_runtime_resume+0x58/0x6c
> LR is at spi_imx_remove+0x1c/0xa8
> pc : [<80632438>]    lr : [<806ebefc>]    psr: 20010013
> sp : f1d81e88  ip : 83c0e204  fp : 00000000
> r10: 00000000  r9 : 00000000  r8 : 82dd9454
> r7 : 82dda054  r6 : 810f82f0  r5 : 00000004  r4 : 6b6b6b6b
> r3 : 6b6b6c53  r2 : 85321240  r1 : 00000004  r0 : 6b6b6b6b
> Flags: nzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
> Control: 10c5387d  Table: 1687c04a  DAC: 00000051
>
> Register r12 information: slab kmalloc-64 start 83c0e180 data offset 64 pointer offset 68 size 64 allocated at kobject_set_name_vargs+0x2c/0xa0
>     kmalloc_node_track_caller_noprof+0x14c/0x37c
>     kvasprintf+0x5c/0xcc
>     kobject_set_name_vargs+0x2c/0xa0
>     dev_set_name+0x2c/0x58
>     spi_register_controller+0xcc/0xc48
>     spi_imx_probe+0x41c/0x694
>     platform_probe+0x5c/0xb0
>     really_probe+0xe0/0x3cc
>     __driver_probe_device+0x9c/0x1e0
>     driver_probe_device+0x30/0xc0
>     __driver_attach+0x11c/0x1cc
>     bus_for_each_dev+0x7c/0xcc
>     bus_add_driver+0xe0/0x220
>     driver_register+0x7c/0x114
>     do_one_initcall+0x58/0x240
>     kernel_init_freeable+0x198/0x1f4
>  Free path:
>     kobject_put+0xd0/0x29c
>     spi_imx_remove+0x10/0xa8
>     platform_remove+0x20/0x5c
>     device_release_driver_internal+0x184/0x1f0
>     unbind_store+0x54/0x90
>     kernfs_fop_write_iter+0xfc/0x1e8
>     vfs_write+0x25c/0x450
>     ksys_write+0x70/0xf0
>     ret_fast_syscall+0x0/0x54
>
> Call trace:
>  __pm_runtime_resume from spi_imx_remove+0x1c/0xa8
>  spi_imx_remove from platform_remove+0x20/0x5c
>  platform_remove from device_release_driver_internal+0x184/0x1f0
>  device_release_driver_internal from unbind_store+0x54/0x90
>  unbind_store from kernfs_fop_write_iter+0xfc/0x1e8
>  kernfs_fop_write_iter from vfs_write+0x25c/0x450
>  vfs_write from ksys_write+0x70/0xf0
>  ksys_write from ret_fast_syscall+0x0/0x54
>
> Fixes: 307c897db762 ("spi: spi-imx: replace struct spi_imx_data::bitbang by pointer to struct spi_controller")
> Signed-off-by: Kirill Yatsenko <kirill.yatsenko@xxxxxxxxxxxxxxx>

Avoid send v2 with v1 message id in future, it should be new email thread.

Reviewed-by: Frank Li <Frank.Li@xxxxxxx>


> ---
> Changes in v2:
>             Shorter Kernel oops message
> ---
>  drivers/spi/spi-imx.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
> index 4a56a5b16e12..14834c4e839a 100644
> --- a/drivers/spi/spi-imx.c
> +++ b/drivers/spi/spi-imx.c
> @@ -1854,7 +1854,7 @@ static int spi_imx_probe(struct platform_device *pdev)
>  	spi_imx->devtype_data->intctrl(spi_imx, 0);
>
>  	controller->dev.of_node = pdev->dev.of_node;
> -	ret = spi_register_controller(controller);
> +	ret = devm_spi_register_controller(&pdev->dev, controller);
>  	if (ret) {
>  		dev_err_probe(&pdev->dev, ret, "register controller failed\n");
>  		goto out_register_controller;
> @@ -1900,8 +1900,6 @@ static void spi_imx_remove(struct platform_device *pdev)
>  	struct spi_imx_data *spi_imx = spi_controller_get_devdata(controller);
>  	int ret;
>
> -	spi_unregister_controller(controller);
> -
>  	ret = pm_runtime_get_sync(spi_imx->dev);
>  	if (ret >= 0)
>  		writel(0, spi_imx->base + MXC_CSPICTRL);
> --
> 2.34.1
>