Re: [PATCH] nvmem: rmem: Make reserved region name unique

[Stefan Wahren]

Hi Ivan,

Am 11.04.23 um 15:50 schrieb Ivan T. Ivanov:
> They could be multiple reserved memory regions,
> so let's make their names unique.
>
> This fixes following kernel error:
>
> [    9.831285] sysfs: cannot create duplicate filename '/bus/nvmem/devices/rmem0'

could you please provide more background information:

- are two instances of rmem trying to create this file?
- which exact platform is affect (Raspberry Pi 4), because the Hardware 
name from the trace is useless?
- could you provide some reliable scenario/config to reproduce this issue?

> [    9.831304] CPU: 3 PID: 467 Comm: (udev-worker) Not tainted 6.2.9-1-default #1 openSUSE Tumbleweed a4aeb3a90c0f23041a8a7944b12739b07585f009
> [    9.831326] Hardware name: raspberrypi rpi/rpi, BIOS 2023.01 01/01/2023
> [    9.831335] Call trace:
> [    9.831343]  dump_backtrace+0xe4/0x140
> [    9.831366]  show_stack+0x20/0x30
> [    9.831379]  dump_stack_lvl+0x64/0x80
> [    9.831398]  dump_stack+0x18/0x34
> [    9.831410]  sysfs_warn_dup+0x6c/0x90
> [    9.831424]  sysfs_do_create_link_sd+0xf8/0x100
> [    9.831437]  sysfs_create_link+0x28/0x50
> [    9.831449]  bus_add_device+0x70/0x190
> [    9.831468]  device_add+0x3e8/0x84c
> [    9.831481]  nvmem_register+0x85c/0x9f0
> [    9.831500]  devm_nvmem_register+0x24/0x70
> [    9.831517]  rmem_probe+0xa0/0xf4 [nvmem_rmem 649243b01e5e28ee94e4dd53bd13b6ececa836f8]
> [    9.831555]  platform_probe+0x70/0xd0
> [    9.831566]  really_probe+0xc8/0x3e4
> [    9.831582]  __driver_probe_device+0x84/0x190
> [    9.831598]  driver_probe_device+0x44/0x11c
> [    9.831613]  __driver_attach+0xf8/0x200
> [    9.831629]  bus_for_each_dev+0x78/0xd0
> [    9.831643]  driver_attach+0x2c/0x40
> [    9.831657]  bus_add_driver+0x188/0x250
> [    9.831672]  driver_register+0x80/0x13c
> [    9.831688]  __platform_driver_register+0x30/0x40
> [    9.831699]  rmem_driver_init+0x28/0x1000 [nvmem_rmem 649243b01e5e28ee94e4dd53bd13b6ececa836f8]
> [    9.831727]  do_one_initcall+0x48/0x2bc
> [    9.831740]  do_init_module+0x50/0x1f0
> [    9.831753]  load_module+0x1e54/0x2250
> [    9.831763]  __do_sys_init_module+0x2ac/0x2f0
> [    9.831774]  __arm64_sys_init_module+0x24/0x30
> [    9.831785]  invoke_syscall+0x78/0x100
> [    9.831803]  el0_svc_common.constprop.0+0x15c/0x180
> [    9.831820]  do_el0_svc+0x40/0xb0
> [    9.831836]  el0_svc+0x34/0x134
> [    9.831850]  el0t_64_sync_handler+0x114/0x120
> [    9.831865]  el0t_64_sync+0x1a4/0x1a8
> [    9.831956] rmem: probe of 3ef62ce0.nvram failed with error -17
>
> Some background information about the issue could be found here:
> https://bugzilla.suse.com/show_bug.cgi?id=1206846
>
> Signed-off-by: Ivan T. Ivanov <iivanov@xxxxxxx>
> ---
>   drivers/nvmem/rmem.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/nvmem/rmem.c b/drivers/nvmem/rmem.c
> index 80cb187f1481..77c70a47d519 100644
> --- a/drivers/nvmem/rmem.c
> +++ b/drivers/nvmem/rmem.c
> @@ -70,7 +70,7 @@ static int rmem_probe(struct platform_device *pdev)
>   
>   	config.dev = dev;
>   	config.priv = priv;
> -	config.name = "rmem";
> +	config.name = dev_name(dev);

AFAIR changing userspace isn't great because application could rely on 
the filename prefix.

What is the result after applying this patch:

ls bus/nvmem/devices/rmem*

>   	config.size = mem->size;
>   	config.reg_read = rmem_read;
>