netdev - Re: [PATCH] wil6210: fix debugfs_simple

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: <08e22040-6e8d-75d1-c0ec-37818435eeba@huawei.com>
Date:   Fri, 5 Oct 2018 19:51:18 +0800
From:   YueHaibing <yuehaibing@...wei.com>
To:     Kalle Valo <kvalo@...eaurora.org>
CC:     Maya Erez <merez@...eaurora.org>, <linux-wireless@...r.kernel.org>,
        <wil6210@....qualcomm.com>, <kernel-janitors@...r.kernel.org>,
        <netdev@...r.kernel.org>
Subject: Re: [PATCH] wil6210: fix debugfs_simple_attr.cocci warnings

On 2018/10/5 19:04, Kalle Valo wrote:
> YueHaibing <yuehaibing@...wei.com> writes:
> 
>> Use DEFINE_DEBUGFS_ATTRIBUTE rather than DEFINE_SIMPLE_ATTRIBUTE
>> for debugfs files.
>>
>> Semantic patch information:
>> Rationale: DEFINE_SIMPLE_ATTRIBUTE + debugfs_create_file()
>> imposes some significant overhead as compared to
>> DEFINE_DEBUGFS_ATTRIBUTE + debugfs_create_file_unsafe().
>>
>> Generated by: scripts/coccinelle/api/debugfs/debugfs_simple_attr.cocci
> 
> Just out of curiosity, what kind of overhead are we talking about here?

commit 5103068eaca2 ("debugfs, coccinelle: check for obsolete DEFINE_SIMPLE_ATTRIBUTE() usage")
said this:

    In order to protect against file removal races, debugfs files created via
    debugfs_create_file() now get wrapped by a struct file_operations at their
    opening.

    If the original struct file_operations are known to be safe against removal
    races by themselves already, the proxy creation may be bypassed by creating
    the files through debugfs_create_file_unsafe().

    In order to help debugfs users who use the common
      DEFINE_SIMPLE_ATTRIBUTE() + debugfs_create_file()
    idiom to transition to removal safe struct file_operations, the helper
    macro DEFINE_DEBUGFS_ATTRIBUTE() has been introduced.


>