lkml.org 
[lkml]   [2022]   [Nov]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 0/8] Remove adis_initial_startup usage
From
Date
On Wed, 2022-11-02 at 16:18 +0200, Ramona Bolboaca wrote:
> Remove adis_initial_startup usage due to the fact that it leads to a
> deadlock.
> The same mutex is acquired twice, without releasing it, once inside
> adis_initial_startup and once inside adis_enable_irq.
> Instead of adis_initial_startup, use __adis_initial_startup.
>

Auchhhh!!! Thanks for catching this... However, the Fixes tag is
pointing to the wrong place. I'm fairly sure I introduced this bug in 

commit b600bd7eb3335 ("iio: adis: do not disabe IRQs in 'adis_init()'")

This was where the call to adis_enable_irq() was moved to
__adis_initial_startup() and effectively creating the deadlock for some
devices (adis->data->unmasked_drdy is not set)...


I guess I did not saw this when bringing in the change because I
probably tested the full series on some device supported by adis16475.c
where this won't trigger.

From a quick look I think it's safe to drop adis_initial_startup() as
it is always called during probe() before registering the IIO device.
We could also just create an unlocked version of adis_enable_irq()
(since we don't need to grab the lock in this path) but likely not
worth the trouble.

- Nuno Sá

\
 
 \ /
  Last update: 2022-11-02 16:26    [W:0.087 / U:0.464 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site