linux-kernel - Re: Can kfree() sleep at runtime?

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <066df211-4d1e-787b-b89d-31b8827ea7a5@gmail.com>
Date:   Fri, 1 Jun 2018 09:22:00 +0800
From:   Jia-Ju Bai <baijiaju1990@...il.com>
To:     Christopher Lameter <cl@...ux.com>,
        Matthew Wilcox <willy@...radead.org>
Cc:     penberg@...nel.org, rientjes@...gle.com, iamjoonsoo.kim@....com,
        akpm@...ux-foundation.org, linux-mm@...ck.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: Can kfree() sleep at runtime?



On 2018/5/31 22:30, Christopher Lameter wrote:
> On Thu, 31 May 2018, Matthew Wilcox wrote:
>
>>> Freeing a page in the page allocator also was traditionally not sleeping.
>>> That has changed?
>> No.  "Your bug" being "The bug in your static analysis tool".  It probably
>> isn't following the data flow correctly (or deeply enough).
> Well ok this is not going to trigger for kfree(), this is x86 specific and
> requires CONFIG_DEBUG_PAGEALLOC and a free of a page in a huge page.
>
> Ok that is a very contorted situation but how would a static checker deal
> with that?

I admit that my tool does not follow the data flow well, and I need to 
improve it.
In this case of kfree(), I want know how the data flow leads to my mistake.


Best wishes,
Jia-Ju Bai