linux-kernel - Re: Question about x86/mm/gup.c's use of disabled interrupts

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>] [day] [month] [year] [list]

Date:	Wed, 18 Mar 2009 16:37:24 -0700
From:	Jeremy Fitzhardinge <jeremy@...p.org>
To:	Shentino <shentino@...il.com>
CC:	Avi Kivity <avi@...hat.com>, Nick Piggin <nickpiggin@...oo.com.au>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Linux Memory Management List <linux-mm@...ck.org>,
	Xen-devel <xen-devel@...ts.xensource.com>,
	Jan Beulich <jbeulich@...ell.com>, Ingo Molnar <mingo@...e.hu>
Subject: Re: Question about x86/mm/gup.c's use of disabled interrupts

Shentino wrote:
> But, does a CPU running a task in userspace effectively have a read 
> lock on the page tables?

No.  A process has its own user pagetable which the kernel maintains on 
its behalf.  The kernel will briefly take locks on it while doing 
modifications, mostly to deal with multithreaded usermode code running 
on multiple cpus.

    J
--
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/