linux-kernel - Re: [PATCH RESEND v3 0/2] dmaengine: idxd: Fix refcount and cleanup issues on module unload

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Message-ID: <87tt2tkvy2.fsf@intel.com>
Date: Wed, 30 Jul 2025 18:09:25 -0700
From: Vinicius Costa Gomes <vinicius.gomes@...el.com>
To: Yi Sun <yi.sun@...el.com>, vkoul@...nel.org, dave.jiang@...el.com,
 fenghuay@...dia.com, xueshuai@...ux.alibaba.com
Cc: dmaengine@...r.kernel.org, linux-kernel@...r.kernel.org,
 yi.sun@...el.com, gordon.jin@...el.com
Subject: Re: [PATCH RESEND v3 0/2] dmaengine: idxd: Fix refcount and cleanup
 issues on module unload

Yi Sun <yi.sun@...el.com> writes:

> This patch series addresses two issues related to the device reference
> counting and cleanup path in the idxd driver.
>
> Recent changes introduced improper put_device() calls and duplicated
> cleanup logic, leading to refcount underflow and potential use-after-free
> during module unload.
>
> Patch 1 removes an unnecessary call to idxd_free(), which could result in a
> use-after-free, because the function idxd_conf_device_release already
> covers everything done in idxd_free. The newly added idxd_free in commit
> 90022b3 doesn't resolve any memory leaks, but introduces several duplicated
> cleanup.
>
> Patch 2 refactors the cleanup to avoid redundant put_device() calls
> introduced in commit a409e919ca3. The existing idxd_unregister_devices()
> already handles proper device reference release.
>
> Both patches have been verified on hardware platform.
>
> Both patches have been run through `checkpatch.pl`. Patch 2 gets 1 error
> and 1 warning. But these appear to be limitations in the checkpatch script
> itself, not reflect issues with the patches.
>
> ---

For the series:

Acked-by: Vinicius Costa Gomes <vinicius.gomes@...el.com>


Cheers,
-- 
Vinicius