From: "Danilo Krummrich" <dakr@kernel.org>
To: "Greg KH" <gregkh@linuxfoundation.org>
Cc: "Yichong Chen" <chenyichong@uniontech.com>, <rafael@kernel.org>,
<djakov@kernel.org>, <quic_mdtipton@quicinc.com>,
<vkoul@kernel.org>, <yung-chuan.liao@linux.intel.com>,
<pierre-louis.bossart@linux.dev>, <driver-core@lists.linux.dev>,
<linux-kernel@vger.kernel.org>, <linux-pm@vger.kernel.org>,
<linux-sound@vger.kernel.org>
Subject: Re: [PATCH v3 0/3] debugfs: make debugfs_create_str() read-only
Date: Thu, 01 Oct 2026 15:10:45 +0200 [thread overview]
Message-ID: <DLTIZ3CNCQDS.24NN9OMJG7AXA@kernel.org> (raw)
In-Reply-To: <2026100153-unmanaged-impart-3adf@gregkh>
On Thu Oct 1, 2026 at 2:51 PM CEST, Greg KH wrote:
> On Fri, Aug 07, 2026 at 06:00:50PM +0800, Yichong Chen wrote:
>> debugfs_create_str() has a generic write implementation that replaces the
>> backing string. Concurrent writers can race and free the same old string
>> twice.
>>
>> Instead of adding more locking to the generic helper, convert the existing
>> writable in-tree users to local file operations and make
>> debugfs_create_str() read-only.
>>
>> Changes since v2:
>> - Use scoped mutex guards in the interconnect and SoundWire conversions.
>> - Clarify why GFP_KERNEL is safe in the interconnect conversion after the
>> RCU read-side critical section is removed.
>> - Drop the unnecessary firmware_file = NULL assignment in the SoundWire
>> exit path.
>> - Use WARN() instead of WARN_ONCE() so each writable debugfs_create_str()
>> caller can be reported.
>
> Sorry for the delay, now applied.
This series fell through the cracks on my end. I also reported this issue in [1]
and I agree making debugfs_create_str() read-only is the best fix for now.
However, it duplicates code and I think having a proper helper as suggested in
[1] would be nice follow-up.
[1] https://lore.kernel.org/driver-core/DLPDB44JJRGJ.3K6JNS746M7QC@kernel.org/
next prev parent reply other threads:[~2026-10-01 13:10 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-07 10:00 Yichong Chen
2026-08-07 10:00 ` [PATCH v3 1/3] interconnect: debugfs: replace writable string helper Yichong Chen
2026-08-07 10:00 ` [PATCH v3 2/3] soundwire: " Yichong Chen
2026-08-07 10:00 ` [PATCH v3 3/3] debugfs: make debugfs_create_str() read-only Yichong Chen
2026-10-01 12:51 ` [PATCH v3 0/3] " Greg KH
2026-10-01 13:10 ` Danilo Krummrich [this message]
2026-10-01 13:19 ` Greg KH
2026-10-01 13:49 ` Danilo Krummrich
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