linux-kernel - Re: Sleeping in atomic context on device release due to device links

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Date:   Mon, 26 Apr 2021 14:25:00 -0700
From:   Saravana Kannan <saravanak@...gle.com>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Guenter Roeck <linux@...ck-us.net>,
        Marek Szyprowski <m.szyprowski@...sung.com>
Subject: Re: Sleeping in atomic context on device release due to device links

On Mon, Apr 26, 2021 at 10:08 AM Andy Shevchenko
<andy.shevchenko@...il.com> wrote:
>
> Hi!
>
> Is the below already fixed somewhere (v5.12 seems still has it)?
> Or I missed something?
>
> [  186.439095] BUG: sleeping function called from invalid context at
> drivers/gpio/gpiolib.c:1952
> [  186.451666] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid:
> 119, name: kworker/0:2
> [  186.463885] 2 locks held by kworker/0:2/119:
> [  186.470831]  #0: ffff985d8110d338
> ((wq_completion)rcu_gp){....}-{0:0}, at: process_one_work+0x1bc/0x4b0
> [  186.484458]  #1: ffffb1a2c0367e70
> ((work_completion)(&sdp->work)){....}-{0:0}, at:
> process_one_work+0x1bc/0x4b
> 0
> [  186.498732] CPU: 0 PID: 119 Comm: kworker/0:2 Not tainted 5.12.0-rc8+ #168
> [  186.508301] Hardware name: Intel Corporation Merrifield/BODEGA BAY,
> BIOS 542 2015.01.21:18.19.48
> [  186.521000] Workqueue: rcu_gp srcu_invoke_callbacks
> [  186.528515] Call Trace:
> [  186.532288]  dump_stack+0x69/0x8e
> [  186.536964]  ___might_sleep.cold+0x95/0xa2
> [  186.543606]  gpiod_free_commit+0x25/0x170
> [  186.550163]  gpiod_put+0x19/0x40
> [  186.554728]  cleanup+0x1b/0x30 [spi_pxa2xx_platform]
> [  186.562246]  spidev_release+0x24/0x50
> [  186.567243]  device_release+0x34/0x90
> [  186.572228]  kobject_put+0x86/0x1d0
> [  186.577035]  __device_link_free_srcu+0x47/0x70
> [  186.583942]  srcu_invoke_callbacks+0xc8/0x170
> [  186.590720]  process_one_work+0x24d/0x4b0
> [  186.597118]  worker_thread+0x55/0x3c0
> [  186.602030]  ? rescuer_thread+0x390/0x390
> [  186.608373]  kthread+0x137/0x150
> [  186.612834]  ? __kthread_bind_mask+0x60/0x60
> [  186.619446]  ret_from_fork+0x22/0x30
>

This took a few hours to debug, but it looks like a SPI framework bug.
Just that some device link code is exposing the bug.

Basically calling the spi controller cleanup in the device's release
op is wrong for many reasons. I'll send a patch for SPI later.

-Saravana