linux-kernel - Re: [PATCH v2] backlight: qcom-wled: fix unbalanced ovp irq enable

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <280f1e92-36a1-450b-b6df-b36c3aed3c1c@oss.qualcomm.com>
Date: Wed, 22 Oct 2025 19:14:32 +0200
From: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
To: foss@...lselvaraj.com, Lee Jones <lee@...nel.org>,
        Daniel Thompson <danielt@...nel.org>,
        Jingoo Han <jingoohan1@...il.com>, Helge Deller <deller@....de>
Cc: linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        linux-fbdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] backlight: qcom-wled: fix unbalanced ovp irq enable

On 10/21/25 8:53 PM, Joel Selvaraj via B4 Relay wrote:
> From: Joel Selvaraj <foss@...lselvaraj.com>
> 
> In Xiaomi Poco F1 and at least few other devices, the qcom wled driver
> triggers unbalanced ovp irq enable warning like the following during
> boot up.
> 
> [    1.151677] ------------[ cut here ]------------
> [    1.151680] Unbalanced enable for IRQ 176
> [    1.151693] WARNING: CPU: 0 PID: 160 at kernel/irq/manage.c:774 __enable_irq+0x50/0x80
> [    1.151710] Modules linked in:
> [    1.151717] CPU: 0 PID: 160 Comm: kworker/0:11 Not tainted 5.17.0-sdm845 #4
> [    1.151724] Hardware name: Xiaomi Pocophone F1 (DT)
> [    1.151728] Workqueue: events wled_ovp_work
> ...<snip>...
> [    1.151833] Call trace:
> [    1.151836]  __enable_irq+0x50/0x80
> [    1.151841]  enable_irq+0x48/0xa0
> [    1.151846]  wled_ovp_work+0x18/0x24
> [    1.151850]  process_one_work+0x1d0/0x350
> [    1.151858]  worker_thread+0x13c/0x460
> [    1.151862]  kthread+0x110/0x114
> [    1.151868]  ret_from_fork+0x10/0x20
> [    1.151876] ---[ end trace 0000000000000000 ]---
> 
> Fix it by storing and checking the state of ovp irq before enabling and
> disabling it.
> 
> Signed-off-by: Joel Selvaraj <foss@...lselvaraj.com>
> ---
> I was able to debug the issue a little further. This happens mainly because
> devm_request_threaded_irq already enables the ovp irq during probe. Then ovp
> work gets scheduled when update_status happens and in turn enables the irq again.
> Tracking the status makes it easy to avoid the double irq enable. But I am
> open to try a different approach if there is any suggestion.

Would reverting this change and adding (| IRQF_NO_AUTOEN) to that call
fix it?

Konrad