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 for Android: free password hash cracker in your pocket
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <34bae667-180f-ce97-ee55-12e13ff28ca0@linux.alibaba.com>
Date:   Fri, 2 Jul 2021 18:05:02 +0800
From:   Yaohui Wang <yaohuiwang@...ux.alibaba.com>
To:     Dave Hansen <dave.hansen@...el.com>, tglx@...utronix.de
Cc:     luto@...nel.org, peterz@...radead.org, mingo@...hat.com,
        bp@...en8.de, x86@...nel.org, linux-kernel@...r.kernel.org,
        luoben@...ux.alibaba.com, Tom Lendacky <thomas.lendacky@....com>,
        Brijesh Singh <brijesh.singh@....com>
Subject: Re: [PATCH v3 1/2] x86/ioremap: fix the pfn calculation mistake in
 __ioremap_check_ram()



On 2021/7/1 22:41, Dave Hansen wrote:
> Was this issue found by inspection, or is it causing an actual problem
> in practice?

This issus truly caused terrible perforamnce downgrade in the practice.
When developing an out of tree module in our testing environment,
invoking ioremap() on normal RAM causes apparent CLI lag. The Unixbench
score also decreases a lot (5x slowdown in the worst case).

Debugging such performance issue is extremely difficult, especially when
the code of the faulty module itself is already very complex. I tested
the system in many aspects before finally located this problem.

> Also, it would be really nice to include the original authors when you
> send Fixes: for patches.  BTW, scripts/get_maintainer.pl would have done
> this for you.  I've added Tom and Brijesh.  Please cc them in the future.

I'll pay attention to this in the future. Thank you for your time and
patience!

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ