Re: 2.6.14 kernels and above copy_to_user stupidity with IRQ disabledcheck
From: Jeff V. Merkey
Date: Fri Jan 27 2006 - 16:17:04 EST
Phillip Susi wrote:
jmerkey@xxxxxxxxxxxxxxxx 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(®en_lock, regen_flags);
v = regen_head;
while (v)
{
if (i >= count)
{
spin_unlock_irqrestore(®en_lock, regen_flags);
return -EFAULT;
}
err = copy_to_user(&s[i++], v, sizeof(VIRTUAL_SETUP));
if (err)
{
spin_unlock_irqrestore(®en_lock, regen_flags);
return err;
}
v = v->next;
}
spin_unlock_irqrestore(®en_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(®en_lock, regen_flags);
v = regen_head;
while (v)
{
if (i >= count)
{
spin_unlock_irqrestore(®en_lock, regen_flags);
return 0;
}
P_Copy(&s[i++], v, sizeof(VIRTUAL_SETUP));
v = v->next;
}
spin_unlock_irqrestore(®en_lock, regen_flags);
return 0;
}
Jeff
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