Re: mm: swap: locking in release_pages()

[Alexander Sverdlin]

Hello Michal!

On 05/04/2022 13:45, Michal Hocko wrote:
>>>> 1. Crash of v5.4.170 on an ARM32 machine:
>>>>
>>>> Unable to handle kernel NULL pointer dereference at virtual address 00000104
>>>> pgd = e138149d
>>>> [00000104] *pgd=84d2fd003, *pmd=8ffd6f003
>>>> Internal error: Oops: a07 [#1] PREEMPT SMP ARM
>>>> ...
>>>> CPU: 1 PID: 6172 Comm: AaSysInfoRColle Tainted: G    B      O      5.4.170-... #1
>>>> Hardware name: Keystone
>>>> PC is at release_pages+0x194/0x358
>>>> LR is at release_pages+0x10c/0x358
>>> Which LOC does this correspond to? (faddr2line should give you a nice
>>> output).
>> Sorry, I forgot this info in the initial report:
>>
>> this is indeed the del_page_from_lru_list() in this crash.
> Could you be more specific please? Is the problem in list_del or
> update_lru_size?

static inline void __list_del(struct list_head * prev, struct list_head * next)
{
        next->prev = prev;    <--

-- 
Best regards,
Alexander Sverdlin.