linux-kernel - Re: [PATCH v2 4/5] uprobes: cleanup and document write_opcode()->lock_page(old

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: <20120709102922.GD32393@linux.vnet.ibm.com>
Date:	Mon, 9 Jul 2012 15:59:22 +0530
From:	Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
To:	Oleg Nesterov <oleg@...hat.com>
Cc:	Ingo Molnar <mingo@...e.hu>, Peter Zijlstra <peterz@...radead.org>,
	Ananth N Mavinakayanahalli <ananth@...ibm.com>,
	Anton Arapov <anton@...hat.com>,
	Hugh Dickins <hughd@...gle.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 4/5] uprobes: cleanup and document
 write_opcode()->lock_page(old_page)

* Oleg Nesterov <oleg@...hat.com> [2012-06-24 17:00:53]:

> The comment above write_opcode()->lock_page(old_page) tells about
> the race with do_wp_page(). I don't really understand which exactly
> race it means, but afaics this lock_page() was not enough to close
> all races with do_wp_page().
> 
> Anyway, since 77fc4af1 this code is always called with ->mmap_sem
> hold for writing so we can forget about do_wp_page().
> 
> However, we can't simply remove this lock_page(), and the only
> (afaics) reason is __replace_page()->try_to_free_swap().
> 
> Nothing in write_opcode() needs it, move it into __replace_page()
> and fix the comment.
> 
> Signed-off-by: Oleg Nesterov <oleg@...hat.com>

Acked-by: Srikar Dronamraju <srikar@...ux.vnet.ibm.com>

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/