From: Keith Owens <kaos@ocs.com.au>
To: Andreas Schwab <schwab@suse.de>
Cc: Todd Inglett <tinglett@vnet.ibm.com>,
Alexander Viro <viro@math.psu.edu>,
linux-kernel@vger.kernel.org
Subject: Re: SMP races in proc with thread_struct
Date: Sat, 05 May 2001 09:27:28 +1000 [thread overview]
Message-ID: <12062.989018848@ocs3.ocs-net> (raw)
In-Reply-To: Your message of "04 May 2001 15:11:37 +0200." <jer8y52r92.fsf@hawking.suse.de>
On 04 May 2001 15:11:37 +0200,
Andreas Schwab <schwab@suse.de> wrote:
>Keith Owens <kaos@ocs.com.au> writes:
>|> Wrap the reference to the parent task structure with exception table
>|> recovery code, like copy_from_user().
>
>Exception tables only protect accesses to user virtual memory. Kernel
>memory references must always be valid in the first place.
Wrong. Exception tables say that if the kernel gets an exception
between labels A and B then branch to fixup label C. See show_regs()
in arch/i386/kernel/process.c and wrmsr_eio() in arch/i386/kernel/msr.c
for examples which do not depend on user virtual memory.
next prev parent reply other threads:[~2001-05-04 23:27 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-05-01 14:30 SMP races in proc with thread_struct Todd Inglett
2001-05-01 16:50 ` Alexander Viro
2001-05-03 11:47 ` Todd Inglett
2001-05-04 12:34 ` Todd Inglett
2001-05-04 12:46 ` Keith Owens
2001-05-04 13:11 ` Andreas Schwab
2001-05-04 13:38 ` Brian Gerst
2001-05-04 23:27 ` Keith Owens [this message]
2001-05-04 14:21 ` Andreas Ferber
2001-05-04 15:18 ` Todd Inglett
2001-05-04 16:04 ` Alexander Viro
2001-05-04 17:52 ` [PATCH][RFC] " Alexander Viro
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