Re: [PATCH v8 13/19] locking/rwsem: Make rwsem->owner an atomic_long_t

From: Luis Henriques
Date: Sun Jul 21 2019 - 16:49:58 EST


Waiman Long <longman@xxxxxxxxxx> writes:

> On 7/20/19 4:41 AM, Luis Henriques wrote:
>> "Linus Torvalds" <torvalds@xxxxxxxxxxxxxxxxxxxx> writes:
>>
>>> On Fri, Jul 19, 2019 at 12:32 PM Waiman Long <longman@xxxxxxxxxx> wrote:
>>>> This patch shouldn't change the behavior of the rwsem code. The code
>>>> only access data within the rw_semaphore structures. I don't know why it
>>>> will cause a KASAN error. I will have to reproduce it and figure out
>>>> exactly which statement is doing the invalid access.
>>> The stack traces should show line numbers if you run them through
>>> scripts/decode_stacktrace.sh.
>>>
>>> You need to have debug info enabled for that, though.
>>>
>>> Luis?
>>>
>>> Linus
>> Yep, sure. And I should have done this in the initial report. It's a
>> different trace, I had to recompile the kernel.
>>
>> (I'm also adding Jeff to the CC list.)
>>
>> Cheers,
>
> Thanks for the information. I think I know where the problem is. Would
> you mind applying the attached patch to see if it can fix the KASAN error.

Yep, that seems to work -- I can't reproduce the error anymore (and
sorry for the delay). Thanks! And feel free to add my Tested-by.

Cheers,
--
Luis