From: liyu <liyu@ccoss.com.cn>
To: Al Viro <viro@ftp.linux.org.uk>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [WTF?] sys_tas() on m32r
Date: Fri, 23 Dec 2005 15:50:32 +0800 [thread overview]
Message-ID: <43ABAC48.20004@ccoss.com.cn> (raw)
In-Reply-To: <20051223061556.GR27946@ftp.linux.org.uk>
Al Viro 写道:
>asmlinkage int sys_tas(int *addr)
>{
> int oldval;
> unsigned long flags;
>
> if (!access_ok(VERIFY_WRITE, addr, sizeof (int)))
> return -EFAULT;
> local_irq_save(flags);
> oldval = *addr;
> if (!oldval)
> *addr = 1;
> local_irq_restore(flags);
> return oldval;
>}
>in arch/m32r/kernel/sys_m32r.c. Trivial oops *AND* ability to trigger
>IO with interrupts disabled.
>-
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The memory that parameter addr pointer is in user-space.
To access these memory, you should use function like copy_from_user().
-liyu
next prev parent reply other threads:[~2005-12-23 7:50 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-12-23 6:15 [WTF?] sys_tas() on m32r Al Viro
2005-12-23 7:50 ` liyu [this message]
2005-12-23 7:54 ` Al Viro
2005-12-23 13:55 ` Andrew Morton
2005-12-23 19:10 ` Lee Revell
2005-12-27 6:36 ` Hirokazu Takata
2005-12-27 9:34 ` Jesper Juhl
2005-12-27 5:27 ` Hirokazu Takata
2005-12-27 13:22 ` Andrew Morton
2005-12-28 0:36 ` Hirokazu Takata
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