linux-kernel - Re: [PATCH] crypto: caam: fix netdev memory leak in dpaa2_caam

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Message-ID: <4a5b1ada-0602-4f43-b09b-ba1a8da26f21@windriver.com>
Date: Fri, 16 Jan 2026 18:14:37 +0800
From: "Chang, Jianpeng (CN)" <Jianpeng.Chang.CN@...driver.com>
To: Breno Leitao <leitao@...ian.org>
Cc: horia.geanta@....com, pankaj.gupta@....com, gaurav.jain@....com,
        herbert@...dor.apana.org.au, davem@...emloft.net, kuba@...nel.org,
        linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] crypto: caam: fix netdev memory leak in dpaa2_caam_probe



On 1/16/2026 5:46 PM, Breno Leitao wrote:
> CAUTION: This email comes from a non Wind River email account!
> Do not click links or open attachments unless you recognize the sender and know the content is safe.
> 
> On Fri, Jan 16, 2026 at 09:44:55AM +0800, Jianpeng Chang wrote:
>> When commit 0e1a4d427f58 ("crypto: caam: Unembed net_dev structure in
>> dpaa2") converted embedded net_device to dynamically allocated pointers,
>> it added cleanup in dpaa2_dpseci_disable() but missed adding cleanup in
>> dpaa2_dpseci_free() for error paths.
>>
>> This causes memory leaks when dpaa2_dpseci_dpio_setup() fails during probe
>> due to DPIO devices not being ready yet. The kernel's deferred probe
>> mechanism handles the retry successfully, but the netdevs allocated during
>> the failed probe attempt are never freed, resulting in kmemleak reports
>> showing multiple leaked netdev-related allocations all traced back to
>> dpaa2_caam_probe().
>>
>> Fix this by preserving the CPU mask of allocated netdevs during setup and
>> using it for cleanup in dpaa2_dpseci_free(). This approach ensures that
>> only the CPUs that actually had netdevs allocated will be cleaned up,
>> avoiding potential issues with CPU hotplug scenarios.
>>
>> Fixes: 0e1a4d427f58 ("crypto: caam: Unembed net_dev structure in dpaa2")
>> Signed-off-by: Jianpeng Chang <jianpeng.chang.cn@...driver.com>
>> ---
>>   drivers/crypto/caam/caamalg_qi2.c | 31 ++++++++++++++++---------------
>>   drivers/crypto/caam/caamalg_qi2.h |  2 ++
>>   2 files changed, 18 insertions(+), 15 deletions(-)
>>
>> diff --git a/drivers/crypto/caam/caamalg_qi2.c b/drivers/crypto/caam/caamalg_qi2.c
>> index 107ccb2ade42..a66c62174a0f 100644
>> --- a/drivers/crypto/caam/caamalg_qi2.c
>> +++ b/drivers/crypto/caam/caamalg_qi2.c
>> @@ -4810,6 +4810,17 @@ static void dpaa2_dpseci_congestion_free(struct dpaa2_caam_priv *priv)
>>        kfree(priv->cscn_mem);
>>   }
>>
>> +static void free_dpaa2_pcpu_netdev(struct dpaa2_caam_priv *priv, const cpumask_t *cpus)
>> +{
>> +     struct dpaa2_caam_priv_per_cpu *ppriv;
>> +     int i;
>> +
>> +     for_each_cpu(i, cpus) {
>> +             ppriv = per_cpu_ptr(priv->ppriv, i);
>> +             free_netdev(ppriv->net_dev);
>> +     }
>> +}
> 
> Why is the function being moved here? Please keep code movement separate
> from functional changes, or at minimum explain why the move is necessary
> in the commit message.
Thank you for the feedback.

I moved the function because I thought reusing existing code would be 
cleaner in dpaa2_dpseci_free. I will add the explain in commit message.

For future reference, what's the preferred approach when needing to 
reuse a simple function (4-line loop) defined later in the file - 
forward declaration, move it with a separate change or just implement 
directly?
Thanks for the guidance.

Regards,
Jianpeng