Hello,
On Tue, Apr 18, 2017 at 10:12:16AM +0100, Andre Przywara wrote:
> Yeah, so I stack-dumped on the zero allocations and indeed they are
> called from cleanup functions:
> drivers/pinctrl/pinmux.c:pinmux_generic_free_functions():
> devm_kzalloc(sizeof(*indices) * pctldev->num_functions, ...)
> (and another one I don't know from the top of the my head, logs at home)
>
> So my hunch was that once EPROBE_DEFER triggers the devres cleanup, it
> uses some reverse list traversal to release all allocated resources
> (backwards!), so missing those which get (appended) during the process.
> But I don't think that would not work with the locking.
> So I have to dig deeper tonight in my logs.
If this is a valid use case, we can change devm to repeat till empty
but it's a weird thing to do to allocate from a release function.
So, something like this. Only compile tested.
Thanks.
diff --git a/drivers/base/devres.c b/drivers/base/devres.c
index 71d5770..d2a9f34 100644
--- a/drivers/base/devres.c
+++ b/drivers/base/devres.c
@@ -509,13 +509,21 @@ static int release_nodes(struct device *dev, struct
list_head *first,
int devres_release_all(struct device *dev)
{
unsigned long flags;
+ int cnt = 0, ret;
/* Looks like an uninitialized device structure */
if (WARN_ON(dev->devres_head.next == NULL))
return -ENODEV;
- spin_lock_irqsave(&dev->devres_lock, flags);
- return release_nodes(dev, dev->devres_head.next, &dev->devres_head,
- flags);
+
+ /* Release callbacks may create new nodes, repeat till empty */
+ do {
+ spin_lock_irqsave(&dev->devres_lock, flags);
+ ret = release_nodes(dev, dev->devres_head.next,
+ &dev->devres_head, flags);
+ cnt += ret;
+ } while (ret);
+
+ return cnt;
}
/**
