This is a note to let you know that I've just added the patch titled
Input: fix regression when re-registering input handlers
to the 6.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
input-fix-regression-when-re-registering-input-handl.patch
and it can be found in the queue-6.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 0284dac550ec179dc0ddc39ab67ba9f172876b4f
Author: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Date: Sun Oct 27 22:31:15 2024 -0700
Input: fix regression when re-registering input handlers
[ Upstream commit 071b24b54d2d05fbf39ddbb27dee08abd1d713f3 ]
Commit d469647bafd9 ("Input: simplify event handling logic") introduced
code that would set handler->events() method to either
input_handler_events_filter() or input_handler_events_default() or
input_handler_events_null(), depending on the kind of input handler
(a filter or a regular one) we are dealing with. Unfortunately this
breaks cases when we try to re-register the same filter (as is the case
with sysrq handler): after initial registration the handler will have 2
event handling methods defined, and will run afoul of the check in
input_handler_check_methods():
input: input_handler_check_methods: only one event processing method can be defined (sysrq)
sysrq: Failed to register input handler, error -22
Fix this by adding handle_events() method to input_handle structure and
setting it up when registering a new input handle according to event
handling methods defined in associated input_handler structure, thus
avoiding modifying the input_handler structure.
Reported-by: "Ned T. Crigler" <crigler@xxxxxxxxx>
Reported-by: Christian Heusel <christian@xxxxxxxxx>
Tested-by: "Ned T. Crigler" <crigler@xxxxxxxxx>
Tested-by: Peter Seiderer <ps.report@xxxxxxx>
Fixes: d469647bafd9 ("Input: simplify event handling logic")
Link: https://lore.kernel.org/r/Zx2iQp6csn42PJA7@xavtug
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/input/input.c b/drivers/input/input.c
index 54c57b267b25f..865d3f8e97a66 100644
--- a/drivers/input/input.c
+++ b/drivers/input/input.c
@@ -119,12 +119,12 @@ static void input_pass_values(struct input_dev *dev,
handle = rcu_dereference(dev->grab);
if (handle) {
- count = handle->handler->events(handle, vals, count);
+ count = handle->handle_events(handle, vals, count);
} else {
list_for_each_entry_rcu(handle, &dev->h_list, d_node)
if (handle->open) {
- count = handle->handler->events(handle, vals,
- count);
+ count = handle->handle_events(handle, vals,
+ count);
if (!count)
break;
}
@@ -2537,57 +2537,6 @@ static int input_handler_check_methods(const struct input_handler *handler)
return 0;
}
-/*
- * An implementation of input_handler's events() method that simply
- * invokes handler->event() method for each event one by one.
- */
-static unsigned int input_handler_events_default(struct input_handle *handle,
- struct input_value *vals,
- unsigned int count)
-{
- struct input_handler *handler = handle->handler;
- struct input_value *v;
-
- for (v = vals; v != vals + count; v++)
- handler->event(handle, v->type, v->code, v->value);
-
- return count;
-}
-
-/*
- * An implementation of input_handler's events() method that invokes
- * handler->filter() method for each event one by one and removes events
- * that were filtered out from the "vals" array.
- */
-static unsigned int input_handler_events_filter(struct input_handle *handle,
- struct input_value *vals,
- unsigned int count)
-{
- struct input_handler *handler = handle->handler;
- struct input_value *end = vals;
- struct input_value *v;
-
- for (v = vals; v != vals + count; v++) {
- if (handler->filter(handle, v->type, v->code, v->value))
- continue;
- if (end != v)
- *end = *v;
- end++;
- }
-
- return end - vals;
-}
-
-/*
- * An implementation of input_handler's events() method that does nothing.
- */
-static unsigned int input_handler_events_null(struct input_handle *handle,
- struct input_value *vals,
- unsigned int count)
-{
- return count;
-}
-
/**
* input_register_handler - register a new input handler
* @handler: handler to be registered
@@ -2607,13 +2556,6 @@ int input_register_handler(struct input_handler *handler)
INIT_LIST_HEAD(&handler->h_list);
- if (handler->filter)
- handler->events = input_handler_events_filter;
- else if (handler->event)
- handler->events = input_handler_events_default;
- else if (!handler->events)
- handler->events = input_handler_events_null;
-
error = mutex_lock_interruptible(&input_mutex);
if (error)
return error;
@@ -2687,6 +2629,75 @@ int input_handler_for_each_handle(struct input_handler *handler, void *data,
}
EXPORT_SYMBOL(input_handler_for_each_handle);
+/*
+ * An implementation of input_handle's handle_events() method that simply
+ * invokes handler->event() method for each event one by one.
+ */
+static unsigned int input_handle_events_default(struct input_handle *handle,
+ struct input_value *vals,
+ unsigned int count)
+{
+ struct input_handler *handler = handle->handler;
+ struct input_value *v;
+
+ for (v = vals; v != vals + count; v++)
+ handler->event(handle, v->type, v->code, v->value);
+
+ return count;
+}
+
+/*
+ * An implementation of input_handle's handle_events() method that invokes
+ * handler->filter() method for each event one by one and removes events
+ * that were filtered out from the "vals" array.
+ */
+static unsigned int input_handle_events_filter(struct input_handle *handle,
+ struct input_value *vals,
+ unsigned int count)
+{
+ struct input_handler *handler = handle->handler;
+ struct input_value *end = vals;
+ struct input_value *v;
+
+ for (v = vals; v != vals + count; v++) {
+ if (handler->filter(handle, v->type, v->code, v->value))
+ continue;
+ if (end != v)
+ *end = *v;
+ end++;
+ }
+
+ return end - vals;
+}
+
+/*
+ * An implementation of input_handle's handle_events() method that does nothing.
+ */
+static unsigned int input_handle_events_null(struct input_handle *handle,
+ struct input_value *vals,
+ unsigned int count)
+{
+ return count;
+}
+
+/*
+ * Sets up appropriate handle->event_handler based on the input_handler
+ * associated with the handle.
+ */
+static void input_handle_setup_event_handler(struct input_handle *handle)
+{
+ struct input_handler *handler = handle->handler;
+
+ if (handler->filter)
+ handle->handle_events = input_handle_events_filter;
+ else if (handler->event)
+ handle->handle_events = input_handle_events_default;
+ else if (handler->events)
+ handle->handle_events = handler->events;
+ else
+ handle->handle_events = input_handle_events_null;
+}
+
/**
* input_register_handle - register a new input handle
* @handle: handle to register
@@ -2704,6 +2715,7 @@ int input_register_handle(struct input_handle *handle)
struct input_dev *dev = handle->dev;
int error;
+ input_handle_setup_event_handler(handle);
/*
* We take dev->mutex here to prevent race with
* input_release_device().
diff --git a/include/linux/input.h b/include/linux/input.h
index 89a0be6ee0e23..cd866b020a01d 100644
--- a/include/linux/input.h
+++ b/include/linux/input.h
@@ -339,12 +339,16 @@ struct input_handler {
* @name: name given to the handle by handler that created it
* @dev: input device the handle is attached to
* @handler: handler that works with the device through this handle
+ * @handle_events: event sequence handler. It is set up by the input core
+ * according to event handling method specified in the @handler. See
+ * input_handle_setup_event_handler().
+ * This method is being called by the input core with interrupts disabled
+ * and dev->event_lock spinlock held and so it may not sleep.
* @d_node: used to put the handle on device's list of attached handles
* @h_node: used to put the handle on handler's list of handles from which
* it gets events
*/
struct input_handle {
-
void *private;
int open;
@@ -353,6 +357,10 @@ struct input_handle {
struct input_dev *dev;
struct input_handler *handler;
+ unsigned int (*handle_events)(struct input_handle *handle,
+ struct input_value *vals,
+ unsigned int count);
+
struct list_head d_node;
struct list_head h_node;
};
