Re: [PATCH] interconnect: debugfs: fix devm_kstrdup and kfree mismatch

[Georgi Djakov <djakov@kernel.org>]

On 4/2/26 6:42 PM, Gui-Dong Han wrote:
> On Wed, Mar 18, 2026 at 10:48 AM Gui-Dong Han <hanguidong02@gmail.com> wrote:
>>
>> debugfs_write_file_str() uses standard kfree() to release old strings.
>> Initializing src_node and dst_node with devm_kstrdup() creates a memory
>> management mismatch. If a user writes to these debugfs nodes, the
>> devm-allocated memory is freed via kfree(), leaving a dangling pointer
>> in the device resource list that can lead to a double free.
>>
>> Fix this by using standard kstrdup() instead. Since the interconnect
>> subsystem is strictly built-in and cannot be unloaded as a module, there
>> is no exit path requiring manual cleanup of these strings. The error
>> handling path is also simplified by taking advantage of the fact that
>> kfree(NULL) is a safe no-op.
>>
>> Fixes: 8cc27f5c6dd1 ("interconnect: debugfs: initialize src_node and dst_node to empty strings")
>> Signed-off-by: Gui-Dong Han <hanguidong02@gmail.com>
>> ---
>> I noticed this memory management mismatch while working on similar
>> debugfs string initialization fixes [1] recently.
>>
>> [1] https://lore.kernel.org/driver-core/20260317185920.43387-1-hanguidong02@gmail.com/
> 
> Hello Georgi,
> 
> Gentle ping on this patch.
> 
> Just wanted to note that my other related fix has already been accepted [1].
> 
> Could you please let me know if this fell through the cracks, or if
> you have any feedback or modification requests? I'd be very happy to
> address them.

Hello,

Thanks for the patch! I applied it already and it's available in today's linux-next.

Thanks,
Georgi