On Thu, Nov 30, 2017 at 9:01 AM, Frank Rowand <frowand.list@xxxxxxxxx> wrote:
> On 11/30/17 08:37, Frank Rowand wrote:
>> Hi Colin, Rob,
>>
>> On 11/30/17 07:18, Colin Ian King wrote:
>>> On 30/11/17 12:14, Frank Rowand wrote:
>>>> On 11/29/17 14:17, Colin King wrote:
>>>>> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>>>>>
>>>>> Currently if the call to of_resolve_phandles fails then then ovcs
>>>>> is not kfree'd on the error exit path. Rather than try and make
>>>>> the clean up exit path more convoluted, fix this by just kfree'ing
>>>>> ovcs at the point of error detection and exit via the same exit
>>>>> path.
>>>>>
>>>>> Detected by CoverityScan, CID#1462296 ("Resource Leak")
>>>>>
>>>>> Fixes: f948d6d8b792 ("of: overlay: avoid race condition between applying multiple overlays")
>>>>> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>>>>> ---
>>>>> drivers/of/overlay.c | 4 +++-
>>>>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
>>>>> index 53bc9e3f0b98..6c8efe7d8cbb 100644
>>>>> --- a/drivers/of/overlay.c
>>>>> +++ b/drivers/of/overlay.c
>>>>> @@ -708,8 +708,10 @@ int of_overlay_apply(struct device_node *tree, int *ovcs_id)
>>>>> of_overlay_mutex_lock();
>>>>>
>>>>> ret = of_resolve_phandles(tree);
>>>>> - if (ret)
>>>>> + if (ret) {
>>>>> + kfree(ovcs);
>>>>> goto err_overlay_unlock;
>>>>> + }
>>>>>
>>>>> mutex_lock(&of_mutex);
>>>>>
>>>>>
>>>>
>>>> False coverity warning. ovcs is freed in free_overlay_changeset().
>>>>
>>>
>>> The error exit path is via err_overlay_unlock:
>>>
>>> err_overlay_unlock:
>>> of_overlay_mutex_unlock();
>>>
>>> out:
>>> pr_debug("%s() err=%d\n", __func__, ret);
>>>
>>> return ret;
>>>
>>> ..so there is no call to free_overlay_changeset there.
>>>
>>> Colin
>>>
>>
>> OK, I was looking at 4.15-rc1. You must be looking at a later version where
>> "[PATCH 1/2] of: overlay: Fix cleanup order in of_overlay_apply()" has been
>> applied. Thanks for providing the extra details about the exit path so I
>> could see that.
>>
>> Rob, I think that the fix for cleanup order was not the best way to fix that
>> problem. A better method would have been to move "mutex_lock(&of_mutex);"
>> up 5 lines, to just before calling of_reserve_phandles().
>
> It is getting late (midnight my time), so I really should revisit this all
> tomorrow. My last comment ("move ... up 5 lines") is probably wrong.
>
> I'll look at this after some sleep.
I'm dropping "of: overlay: Fix cleanup order in of_overlay_apply()",
so someone please fix this in the original patch.
Rob
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