lkml.org 
[lkml]   [2006]   [Jan]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: 2.6.14 kernels and above copy_to_user stupidity with IRQ disabled check
Phillip Susi wrote:

> jmerkey@ns1.utah-nac.org wrote:
>
>> OK. Got it. I guess I need to restructure. And BTW, This was a
>> code fragment
>> only, the spinlock gets released when -EFAULT is called -- was just
>> an example.
>>
>> Jeff
>
>
> Unless you have redefined EFAULT in some strange and hideous way, it
> is not "called" and doesn't free the spinlock. EFAULT is defined as a
> literal integer, so you're just returning a number without freeing the
> spinlock.
>
> If you have redefined EFAULT to a macro function call or whatever,
> then don't do that, it's REALLY horrible coding practice.
>
>
No. I posted a code fragment as an example. Here's the actual code:

int dump_regen(VIRTUAL_SETUP *s, ULONG count)
{
register int i = 0;
VIRTUAL_SETUP *v;

spin_lock_irqsave(&regen_lock, regen_flags);
v = regen_head;
while (v)
{
if (i >= count)
{
spin_unlock_irqrestore(&regen_lock, regen_flags);
return -EFAULT;
}

err = copy_to_user(&s[i++], v, sizeof(VIRTUAL_SETUP));
if (err)
{
spin_unlock_irqrestore(&regen_lock, regen_flags);
return err;
}
v = v->next;
}
spin_unlock_irqrestore(&regen_lock, regen_flags);
return 0;
}
Needless to say, this has been restructured to this:

int dump_regen(VIRTUAL_SETUP *s, ULONG count)
{
register int i = 0;
VIRTUAL_SETUP *v;

spin_lock_irqsave(&regen_lock, regen_flags);
v = regen_head;
while (v)
{
if (i >= count)
{
spin_unlock_irqrestore(&regen_lock, regen_flags);
return 0;
}

P_Copy(&s[i++], v, sizeof(VIRTUAL_SETUP));
v = v->next;
}
spin_unlock_irqrestore(&regen_lock, regen_flags);
return 0;
}

Jeff

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

\
 
 \ /
  Last update: 2006-01-27 22:21    [from the cache]
©2003-2011 Jasper Spaans