On Thu, 27 Mar 2003, Dan Eble wrote:
>
> This makes checks like the following (in alloc_skb) asymmetric:
>
> if (in_interrupt() && (gfp_mask & __GFP_WAIT)) {
> static int count = 0;
> if (++count < 5) {
> printk(KERN_ERR "alloc_skb called nonatomically "
> "from interrupt %p\n", NET_CALLER(size));
> BUG();
>
> In a driver I'm writing, this bug was hidden until I switched from using
> write_lock_irqsave() to write_lock_bh(). Shouldn't this bug also be
> announced if interrupts are disabled?
Yeah. It should also probably use "in_atomic()" instead of
"in_interrupt()", since that also finds people who have marked themselves
non-preemptible.
So what the test SHOULD look like is this:
if (gfp_mask & __GFP_WAIT) {
if (in_atomic() || irqs_disabled()) {
static int count = 0;
...
}
}
which should catch all the cases we really care about.
Linus
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