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SubjectRe: [PATCH v2] staging: erofs: keep corrupted fs from crashing kernel in erofs_namei()
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Hi Dan,

On 2019/2/15 15:57, Dan Carpenter wrote:
> On Fri, Feb 15, 2019 at 03:02:25PM +0800, Chao Yu wrote:
>> On 2019/2/1 20:16, Gao Xiang wrote:
>>> + /*
>>> + * on-disk error, let's only BUG_ON in the debugging mode.
>>> + * otherwise, it will return 1 to just skip the invalid name
>>> + * and go on (in consideration of the lookup performance).
>>> + */
>>> + DBG_BUGON(qd->name > qd->end);
>>
>> qd->name == qd->end is not allowed as well?
>>
>> So will it be better to return directly here?
>>
>> if (unlikely(qd->name >= qd->end)) {
>> DBG_BUGON(1);
>> return 1;
>> }
>
> Please don't add likely/unlikely() annotations unless you have
> benchmarked it and it makes a difference.

I tend not to add this branch above since the current logic can handle
qd->name >= qd->end (it only happens in corrupted images) and
it will return 1;

Let's just leave DBG_BUGON(qd->name > qd->end); here for debugging use
(to detect corrupted image in some degree earlier).

Thanks,
Gao Xiang

>
> regards,
> dan carpenter
>
>

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