Re: [syzbot] [mm?] [reiserfs?] kernel panic: stack is corrupted in ___slab_alloc

[Vlastimil Babka]

On 7/10/23 09:43, Dmitry Vyukov wrote:
> On Thu, 6 Jul 2023 at 20:33, Lameter, Christopher
> <cl@xxxxxxxxxxxxxxxxxxxxxx> wrote:
>>
>> On Mon, 3 Jul 2023, Dmitry Vyukov wrote:
>>
>> >> This is happening during while mounting reiserfs, so I'm inclined to think
>> >> it's more of a reisterfs issue than a slab allocator issue :/
>>
>> Have you tried to run with the "slub_debug" kernel option to figure out
>> what got corrupted?
> 
> Can slub_debug detect anything that KASAN can't?

Probably not, KASAN will find out a bad write at the moment it happens,
while slub_debug only later from corrupted red zone/poison.

> I would assume KASAN can detect more bugs (e.g. stack/globals) and
> report way better. And it was already enabled in the config.

Anyway this is a stack corruption, not slab layout corruption. It's probably
hard to distinguish a legitimate stack write from an overrun so even KASAN
could not catch it immediately?