Re: [PATCH v2] iommu: fix smmu initialization memory leak problem

Marion & Christophe JAILLET
2022-12-20T21:39:24Z

Le 20/12/2022 à 04:17, liulongfang a écrit :
> On 2022/12/1 21:31, Will Deacon Wrote:
>> On Thu, Dec 01, 2022 at 08:42:02PM +0800, liulongfang wrote:
>>> On 2022/11/29 23:24, Will Deacon wrote:
>>>> On Tue, Nov 22, 2022 at 08:00:39PM +0800, liulongfang wrote:
>>>>> On 2022/11/22 2:05, Will Deacon wrote:
>>>>>> On Mon, Nov 21, 2022 at 11:04:21AM +0800, Longfang Liu wrote:
>>>>>>> When iommu_device_register() in arm_smmu_device_probe() fails,
>>>>>>> in addition to sysfs needs to be deleted, device should also
>>>>>>> be disabled, and the memory of iopf needs to be released to
>>>>>>> prevent memory leak of iopf.
>>>>>>>
>>>>>>> Changes v1 -> v2:
>>>>>>> -Improve arm_smmu_device_probe() abnormal exit function.
>>>>>>>
>>>>>>> Signed-off-by: Longfang Liu <liulongfang@huawei.com>
>>>>>>> ---
>>>>>>> drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 16 +++++++++++-----
>>>>>>> 1 file changed, 11 insertions(+), 5 deletions(-)
>>>>>>>
>>>>>>> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
>>>>>>> index ab160198edd6..b892f5233f88 100644
>>>>>>> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
>>>>>>> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
>>>>>>> @@ -3815,7 +3815,7 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
>>>>>>> /* Initialise in-memory data structures */
>>>>>>> ret = arm_smmu_init_structures(smmu);
>>>>>>> if (ret)
>>>>>>> - return ret;
>>>>>>> + goto err_iopf;
>>>>>>>
>>>>>>> /* Record our private device structure */
>>>>>>> platform_set_drvdata(pdev, smmu);
>>>>>>> @@ -3826,22 +3826,28 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
>>>>>>> /* Reset the device */
>>>>>>> ret = arm_smmu_device_reset(smmu, bypass);
>>>>>>> if (ret)
>>>>>>> - return ret;
>>>>>>> + goto err_iopf;
>>>>>>>
>>>>>>> /* And we're up. Go go go! */
>>>>>>> ret = iommu_device_sysfs_add(&smmu->iommu, dev, NULL,
>>>>>>> "smmu3.%pa", &ioaddr);
>>>>>>> if (ret)
>>>>>>> - return ret;
>>>>>>> + goto err_reset;
>>>>>>>
>>>>>>> ret = iommu_device_register(&smmu->iommu, &arm_smmu_ops, dev);
>>>>>>> if (ret) {
>>>>>>> dev_err(dev, "Failed to register iommu\n");
>>>>>>> - iommu_device_sysfs_remove(&smmu->iommu);
>>>>>>> - return ret;
>>>>>>> + goto err_sysfs_add;
>>>>>>> }
>>>>>>>
>>>>>>> return 0;
>>>>>>> +err_sysfs_add:
>>>>>>> + iommu_device_sysfs_remove(&smmu->iommu);
>>>>>>> +err_reset:
>>>>>>> + arm_smmu_device_disable(smmu);
>>>>>>> +err_iopf:
>>>>>>> + iopf_queue_free(smmu->evtq.iopf);
>>>>>>> + return ret;
>>>>>> I previously suggested using devres_alloc() for this instead. Did that
>>>>>> not work?
>>>>>>
>>>>> This patch is only for fixing iopf's memory leak.
>>>>> The use of devres_alloc() is an optimization solution for iopf queue management,
>>>>> which is another set of patch matters.
>>>> Great, I look forward to that set of patches!
>>>>
>>> Will this patch be merged into the next branch?
>> I don't plan to merge this one, no. I'll wait for the other patches which do
>> this using devres_alloc() instead.
>>
>> Thanks,
>>
>> Will
>> .
>>
> Hi Christophe:
> "[PATCH] iommu/arm-smmu-v3: Fix an error handling path in arm_smmu_device_probe()"
>
> the patch you sent is the same as mine. The maintainer hopes to optimize the queue
> application part of iopf with devres_alloc().

Hi,

more or less.

You also added a arm_smmu_device_disable() call in the error handling path.
Looks good to me, but should be confirmed by s.o who knows the hardware.

That said, I think that what has been suggested by Will Deacon would be
something like:

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index ab160198edd6..1994990decb8 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2930,6 +2930,11 @@ static int arm_smmu_cmdq_init(struct
arm_smmu_device *smmu)
return 0;
}

+static void arm_smmu_free_queues(void *ptr)
+{
+    iopf_queue_free(ptr);
+}
+
static int arm_smmu_init_queues(struct arm_smmu_device *smmu)
{
int ret;
@@ -2957,6 +2962,11 @@ static int arm_smmu_init_queues(struct
arm_smmu_device *smmu)
smmu->evtq.iopf = iopf_queue_alloc(dev_name(smmu->dev));
if (!smmu->evtq.iopf)
return -ENOMEM;
+
+        ret = devm_add_action_or_reset(smmu->dev, arm_smmu_free_queues,
+                           smmu->evtq.iopf);
+        if (ret)
+            return ret;
}

/* priq */
@@ -3832,16 +3842,21 @@ static int arm_smmu_device_probe(struct
platform_device *pdev)
ret = iommu_device_sysfs_add(&smmu->iommu, dev, NULL,
"smmu3.%pa", &ioaddr);
if (ret)
-        return ret;
+        goto err_reset;

ret = iommu_device_register(&smmu->iommu, &arm_smmu_ops, dev);
if (ret) {
dev_err(dev, "Failed to register iommu\n");
-        iommu_device_sysfs_remove(&smmu->iommu);
-        return ret;
+        goto err_sysfs_add;
}

return 0;
+
+err_sysfs_add:
+    iommu_device_sysfs_remove(&smmu->iommu);
+err_reset:
+    arm_smmu_device_disable(smmu);
+    return ret;
}

static int arm_smmu_device_remove(struct platform_device *pdev)
@@ -3851,7 +3866,6 @@ static int arm_smmu_device_remove(struct
platform_device *pdev)
iommu_device_unregister(&smmu->iommu);
iommu_device_sysfs_remove(&smmu->iommu);
arm_smmu_device_disable(smmu);
-    iopf_queue_free(smmu->evtq.iopf);

return 0;
}

I'm not a really big fan because it adds too much code for me. But I'm
not a maintainer, so let them have the last word on it.
At least, this avoids an odd iopf_queue_free() call that comes from
nowhere without looking deeper in the code.

It has been compile tested only on arm64.

> I hope you can modify it, and I will quit this repair work.

If it please you and Will, feel free to propose it as a v3 of your patch.

CJ

> Thanks,
> Longfang.