Re: WARNING: fs/proc/generic.c:173 __xlate_proc_name

[Bartosz Golaszewski <brgl@xxxxxxxx>]

On Sat, Feb 10, 2024 at 11:06 AM Stefan Wahren <wahrenst@xxxxxxx> wrote:
>
> Hi,
> we are using libgpiod-2.0.1 with Linux 6.1.49 on our Tarragon hardware
> platform. Recently we implemented an application which waits for GPIO
> interrupts and we were able to trigger a warning by naming the owner of
> the GPIO as "R1/S1":
>
> WARNING: CPU: 0 PID: 429 at fs/proc/generic.c:173
> __xlate_proc_name+0x78/0x98 name 'R1/S1'
> CPU: 0 PID: 429 Comm: cb_tarragon_dri Not tainted
> 6.1.49-00019-g9dbc76303a17 #147
> Hardware name: Freescale i.MX6 Ultralite (Device Tree)
> unwind_backtrace from show_stack+0x10/0x14
> show_stack from dump_stack_lvl+0x24/0x2c
> dump_stack_lvl from __warn+0x74/0xbc
> __warn from warn_slowpath_fmt+0xc8/0x120
> warn_slowpath_fmt from __xlate_proc_name+0x78/0x98
> __xlate_proc_name from __proc_create+0x3c/0x284
> __proc_create from _proc_mkdir+0x2c/0x70
> _proc_mkdir from proc_mkdir_data+0x10/0x18
> proc_mkdir_data from register_handler_proc+0xc8/0x118
> register_handler_proc from __setup_irq+0x554/0x664
> __setup_irq from request_threaded_irq+0xac/0x13c
> request_threaded_irq from edge_detector_setup+0xc0/0x1f8
> edge_detector_setup from linereq_create+0x30c/0x384
> linereq_create from vfs_ioctl+0x20/0x38
> vfs_ioctl from sys_ioctl+0xbc/0x8b0
> sys_ioctl from ret_fast_syscall+0x0/0x54
> Exception stack(0xe0b61fa8 to 0xe0b61ff0)
> 1fa0:                   01b019b8 01a9f428 0000000d c250b407 beeae888
> beeae880
> 1fc0: 01b019b8 01a9f428 01af7e40 00000036 beeaeb88 beeaeb80 beeaeb58
> beeaeb60
> 1fe0: 00000036 beeae868 b6a88569 b6a01ae6
> ---[ end trace 0000000000000000 ]---
>
> I'm not sure where this should be fixed.
>

Interesting. Seems as if the interrupt subsystem cannot handle '/' in
the interrupt consumer name. I'm wondering if we should filter out any
'/' in GPIO names when using the lines for interrupts? What do we
replace them with?

Bart