linux-kernel - zram: zram_free_page calls in zram_meta

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-next>] [day] [month] [year] [list]

Date:   Mon, 6 Nov 2023 23:42:31 +0300
From:   Vasily Averin <vasily.averin@...ux.dev>
To:     Sergey Senozhatsky <senozhatsky@...omium.org>,
        Minchan Kim <minchan@...nel.org>
Cc:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        linux-block@...r.kernel.org
Subject: zram: zram_free_page calls in zram_meta_free

The only place where content of zram entry is accessed and even changed without taken zran lock is
zram_free_page() calls from zram_meta_free().

It does not look like problem because zram should not have any users at this point,
however I still do not understand why this is required?

Is it performance optimization? But zram reset is quite rare operation, I doubt it is called
on some performance-critical fast path. Am I missed something perhaps?

I would like to add proper zram_lock/unlock calls around zram_free_page here,
and would like to clarify,perhaps you have any objections?

Thank you,
	Vasily Averin