On 22/02/2024 11:52, Rafael J. Wysocki wrote:
On Thu, Feb 22, 2024 at 11:47 AM Daniel Lezcano
<daniel.lezcano@xxxxxxxxxx> wrote:
On 14/02/2024 13:45, Rafael J. Wysocki wrote:
From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
The current code requires thermal zone creators to pass pointers to
writable ops structures to thermal_zone_device_register_with_trips()
which needs to modify the target struct thermal_zone_device_ops object
if the "critical" operation in it is NULL.
Moreover, the callers of thermal_zone_device_register_with_trips() are
required to hold on to the struct thermal_zone_device_ops object passed
to it until the given thermal zone is unregistered.
Both of these requirements are quite inconvenient, so modify struct
thermal_zone_device to contain struct thermal_zone_device_ops as field and
make thermal_zone_device_register_with_trips() copy the contents of the
struct thermal_zone_device_ops passed to it via a pointer (which can be
const now) to that field.
Also adjust the code using thermal zone ops accordingly and modify
thermal_of_zone_register() to use a local ops variable during
thermal zone registration so ops do not need to be freed in
thermal_of_zone_unregister() any more.
[ ... ]
static void thermal_of_zone_unregister(struct thermal_zone_device *tz)
{
struct thermal_trip *trips = tz->trips;
- struct thermal_zone_device_ops *ops = tz->ops;
thermal_zone_device_disable(tz);
thermal_zone_device_unregister(tz);
kfree(trips);
Not related to the current patch but with patch 1/6. Freeing the trip
points here will lead to a double free given it is already freed from
thermal_zone_device_unregister() after the changes introduces in patch
1, right ?
No, patch [1/6] doesn't free the caller-supplied ops, just copies them
into the local instance. Attempting to free a static ops would not be
a good idea, for example.
I'm referring to the trip points not the ops.
The patch 1 does:
tz = kzalloc(struct_size(tz, trips, num_trips), GFP_KERNEL);
Then the last line of thermal_zone_device_unregister() does:
kfree(tz);
That includes the trip points in the flexible array.
Now in thermal_of_zone_unregister(), we do:
trips = tz->trips;
thermal_zone_device_unregister(tz);
kfree(trips);
Hence double kfree, right?
BTW, thanks for all of the reviews, but this series is not applicable
without the one at
https://lore.kernel.org/linux-pm/6017196.lOV4Wx5bFT@kreacher/
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