On Thu, Jun 20, 2024, at 13:24, Peter Griffin wrote:
> Signed-off-by: Peter Griffin <peter.griffin@xxxxxxxxxx>
> Reviewed-by: Arnd Bergmann <arnd@xxxxxxxx>
> Reviewed-by: Sam Protsenko <semen.protsenko@xxxxxxxxxx>
> ---
> Changes in v2:
> - Keep syscon lock held between checking and adding entry (Krzysztof)
Unfortunately you now have a different bug:
> + /* check if syscon entry already exists */
> + spin_lock(&syscon_list_slock);
> +
> + list_for_each_entry(entry, &syscon_list, list)
> + if (entry->np == np) {
> + syscon = entry;
> + break;
> + }
> +
> + if (syscon) {
> + ret = -EEXIST;
> + goto err_unlock;
> + }
> +
> + syscon = kzalloc(sizeof(*syscon), GFP_KERNEL);
> + if (!syscon) {
> + ret = -ENOMEM;
> + goto err_unlock;
> + }
You can't use GFP_KERNEL while holding a spinlock.
I think the correct way to do this is to move the allocation
before the locked section, and then free it in the failure case.
Arnd
