lkml.org 
[lkml]   [2018]   [Jun]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [Letux-kernel] BUG: drivers/pinctrl/core: races in pinctrl_groups and deferred probing
On Sat, Jun 16, 2018 at 2:08 PM H. Nikolaus Schaller <hns@goldelico.com> wrote:

> [ 0.739501] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_hsusb2_pins selector=0
> [ 0.741638] pinctrl_generic_add_group: pctldev=ee481f80 name=pinmux_hsusb2_2_pins selector=0
> [ 0.742401] pinctrl_generic_add_group: pctldev=ee481e00 name=pinmux_mcbsp1_devconf0_pins selector=0
> [ 0.743072] pinctrl_generic_add_group: pctldev=ee481d00 name=pinmux_tv_acbias_devconf1_pins selector=0
> [ 0.760437] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_uart1_pins selector=1
> [ 0.762268] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_uart2_pins selector=2
> [ 0.763610] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_uart3_pins selector=3
> [ 1.790527] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_twl4030_pins selector=4
> [ 1.799835] pinctrl_generic_add_group: pctldev=ee3cd000 name=pinmux_twl4030_vpins selector=0
> [ 1.969635] pinctrl_generic_add_group: pctldev=ee481f80 name=spi_gpio_pinmux selector=1
> [ 2.164093] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_mmc1_pins selector=5
> [ 2.198242] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_wlan_irq_pin selector=6
> [ 2.374328] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_gpmc_pins selector=7
> [ 2.769989] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_wlan_pins selector=8
> [ 2.785888] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_bt_pins selector=9
> [ 2.802154] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_wlan_irq_pin selector=10
> [ 5.415222] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_dss_dpi_pins selector=11
> [ 6.080566] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_mcbsp1_pins selector=12
> [ 6.182617] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_mcbsp2_pins selector=13
> [ 6.271240] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_mcbsp3_pins selector=14
> [ 6.330718] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_penirq_pins selector=15
> [ 6.368927] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_mcbsp4_pins selector=16
> [ 6.616546] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_camera_pins selector=17
> [ 6.835418] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_camera_pins selector=18
> [ 6.874694] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_camera_pins selector=19
> [ 6.900299] pinctrl_generic_add_group: pctldev=ee3cd180 name=hdq_pins selector=20
> [ 6.937042] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_camera_pins selector=21
> [ 7.062744] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_camera_pins selector=22
> [ 7.108032] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_camera_pins selector=23
> [ 7.145080] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_camera_pins selector=24
> [ 7.197723] pinctrl_generic_add_group: pctldev=ee3cd180 name=backlight_pins_pinmux selector=25
> [ 7.427398] pinctrl_generic_add_group: pctldev=ee3cd180 name=modem_pins selector=26
> [ 7.476562] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_camera_pins selector=27
> [ 7.505981] pinctrl_generic_add_group: pctldev=ee3cd180 name=backlight_pins_pinmux selector=28
> [ 7.564910] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_camera_pins selector=29
> [ 7.894439] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_camera_pins selector=30
> [ 8.207489] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_camera_pins selector=31
> [ 8.311096] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_pps_pins selector=32
> [ 8.340667] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_camera_pins selector=33
> [ 8.414428] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_camera_pins selector=34
> [ 9.231445] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_camera_pins selector=35
> [ 9.446716] pinctrl_generic_add_group: pctldev=ee3cd180 name=pinmux_camera_pins selector=36
> root@letux:~#
>
> But it looks as if we still have duplicate assignments by deferred probing, i.e. some cleanup is
> missing (or is this intended behaviour?).

> But I think the fundamental problem is that the same driver assigns multiple slots if
> probing is deferred.

Indeed.

I think there is a simple way to clean up pinctrl stuff on failed probe. See
https://elixir.bootlin.com/linux/v4.18-rc1/source/drivers/base/dd.c#L416

We only bind pins, and do not perform any actions when failure happens later on.

> 3. I could not observe calls to pinctrl_generic_remove_group()
> 4. this means a stale pointer to the group_desc is still stored in the radix tree
> if driver probing fails

Exactly.

--
With Best Regards,
Andy Shevchenko

\
 
 \ /
  Last update: 2018-06-18 11:41    [W:0.093 / U:0.448 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site