Re: [PATCH v6] mm/slub: avoid accessing metadata when pointer is invalid in object_err()

[Vlastimil Babka <vbabka@suse.cz>]

On 8/5/25 03:24, liqiong wrote:
> 
> 
> 在 2025/8/4 23:19, Vlastimil Babka 写道:
>> On 8/4/25 04:57, Li Qiong wrote:
>>> object_err() reports details of an object for further debugging, such as
>>> the freelist pointer, redzone, etc. However, if the pointer is invalid,
>>> attempting to access object metadata can lead to a crash since it does
>>> not point to a valid object.
>>>
>>> In case the pointer is NULL or check_valid_pointer() returns false for
>>> the pointer, only print the pointer value and skip accessing metadata.
>> We should explain that this is not theoretical so justify the stable cc, so
>> I would add:
>>
>> One known path to the crash is when alloc_consistency_checks() determines
>> the pointer to the allocated object is invalid beause of a freelist
>> corruption, and calls object_err() to report it. The debug code should
>> report and handle the corruption gracefully and not crash in the process.
>>
>> If you agree, I can do this when picking up the patch after merge window, no
>> need to resend.
> 
> Agree, thanks.

Merged to -next, thanks.