Q: Given the following code slice:
```
1 static int edge_detector_setup(struct line *line,
2 			       struct gpio_v2_line_config *lc,
3 			       unsigned int line_idx, u64 edflags)
4 {
5 	u32 debounce_period_us;
6 	unsigned long irqflags = 0;
7 	u64 eflags;
8 	int irq, ret;
9 
10 	eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
11 	if (eflags && !kfifo_initialized(&line->req->events)) {
12 		ret = kfifo_alloc(&line->req->events,
13 				  line->req->event_buffer_size, GFP_KERNEL);
14 		if (ret)
15 			return ret;
16 	}
17 	if (gpio_v2_line_config_debounced(lc, line_idx)) {
18 		debounce_period_us = gpio_v2_line_config_debounce_period(lc, line_idx);
19 		ret = debounce_setup(line, debounce_period_us);
20 		if (ret)
21 			return ret;
22 		line_set_debounce_period(line, debounce_period_us);
23 	}
24 
25 	/* detection disabled or sw debouncer will provide edge detection */
26 	if (!eflags || READ_ONCE(line->sw_debounced))
27 		return 0;
28 
29 	if (IS_ENABLED(CONFIG_HTE) &&
30 	    (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
31 		return hte_edge_setup(line, edflags);
32 
33 	irq = gpiod_to_irq(line->desc);
34 	if (irq < 0)
35 		return -ENXIO;
36 
37 	if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING)
38 		irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
39 			IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
40 	if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
41 		irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
42 			IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
43 	irqflags |= IRQF_ONESHOT;
44 
45 	/* Request a thread to read the events */
46 	ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread,
47 				   irqflags, line->req->label, line);
48 	if (ret)
49 		return ret;
50 
51 	line->irq = irq;
52 	return 0;
53 }
54 static inline int __must_check
55 request_irq(unsigned int irq, irq_handler_t handler, unsigned long flags,
56 	    const char *name, void *dev)
57 {
58 	return request_threaded_irq(irq, handler, NULL, flags, name, dev);
59 }
60 void rb_insert_color(struct rb_node *node, struct rb_root *root)
61 {
62 	__rb_insert(node, root, dummy_rotate);
63 }
64 static u32 gpio_v2_line_config_debounce_period(struct gpio_v2_line_config *lc,
65 					       unsigned int line_idx)
66 {
67 	unsigned int i;
68 	u64 mask = BIT_ULL(line_idx);
69 
70 	for (i = 0; i < lc->num_attrs; i++) {
71 		if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
72 		    (lc->attrs[i].mask & mask))
73 			return lc->attrs[i].attr.debounce_period_us;
74 	}
75 	return 0;
76 }
77 static void supinfo_erase(struct line *line)
78 {
79 	guard(spinlock)(&supinfo_lock);
80 
81 	rb_erase(&line->node, &supinfo_tree);
82 }
83 static int edge_detector_update(struct line *line,
84 				struct gpio_v2_line_config *lc,
85 				unsigned int line_idx, u64 edflags)
86 {
87 	u64 active_edflags = READ_ONCE(line->edflags);
88 	unsigned int debounce_period_us =
89 			gpio_v2_line_config_debounce_period(lc, line_idx);
90 
91 	if ((active_edflags == edflags) &&
92 	    (READ_ONCE(line->debounce_period_us) == debounce_period_us))
93 		return 0;
94 
95 	/* sw debounced and still will be...*/
96 	if (debounce_period_us && READ_ONCE(line->sw_debounced)) {
97 		line_set_debounce_period(line, debounce_period_us);
98 		return 0;
99 	}
100 
101 	/* reconfiguring edge detection or sw debounce being disabled */
102 	if ((line->irq && !READ_ONCE(line->sw_debounced)) ||
103 	    (active_edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE) ||
104 	    (!debounce_period_us && READ_ONCE(line->sw_debounced)))
105 		edge_detector_stop(line);
106 
107 	return edge_detector_setup(line, lc, line_idx, edflags);
108 }
109 static void line_set_debounce_period(struct line *line,
110 				     unsigned int debounce_period_us)
111 {
112 	bool was_suppl = line_has_supinfo(line);
113 
114 	WRITE_ONCE(line->debounce_period_us, debounce_period_us);
115 
116 	/* if supinfo status is unchanged then we're done */
117 	if (line_has_supinfo(line) == was_suppl)
118 		return;
119 
120 	/* supinfo status has changed, so update the tree */
121 	if (was_suppl)
122 		supinfo_erase(line);
123 	else
124 		supinfo_insert(line);
125 }
126 int gpiod_set_debounce(struct gpio_desc *desc, unsigned int debounce)
127 {
128 	unsigned long config;
129 
130 	config = pinconf_to_config_packed(PIN_CONFIG_INPUT_DEBOUNCE, debounce);
131 	return gpiod_set_config(desc, config);
132 }
133 static inline int gpiod_to_irq(const struct gpio_desc *desc)
134 {
135 	/* GPIO can never have been requested */
136 	WARN_ON(desc);
137 	return -EINVAL;
138 }
139 static bool gpio_v2_line_config_debounced(struct gpio_v2_line_config *lc,
140 					  unsigned int line_idx)
141 {
142 	unsigned int i;
143 	u64 mask = BIT_ULL(line_idx);
144 
145 	for (i = 0; i < lc->num_attrs; i++) {
146 		if ((lc->attrs[i].attr.id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE) &&
147 		    (lc->attrs[i].mask & mask))
148 			return true;
149 	}
150 	return false;
151 }
152 int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc)
153 {
154 	might_sleep_if(extra_checks);
155 	VALIDATE_DESC(desc);
156 	return gpiod_get_raw_value_commit(desc);
157 }
158 int gpiod_set_config(struct gpio_desc *desc, unsigned long config)
159 {
160 	struct gpio_chip *gc;
161 
162 	VALIDATE_DESC(desc);
163 	gc = desc->gdev->chip;
164 
165 	return gpio_do_set_config(gc, gpio_chip_hwgpio(desc), config);
166 }
167 sub WARN {
168 	my ($type, $msg) = @_;
169 
170 	if (report("WARNING", $type, $msg)) {
171 		our $clean = 0;
172 		our $cnt_warn++;
173 		return 1;
174 	}
175 	return 0;
176 }
177 int hte_init_line_attr(struct hte_ts_desc *desc, u32 line_id,
178 		       unsigned long edge_flags, const char *name, void *data)
179 {
180 	if (!desc)
181 		return -EINVAL;
182 
183 	memset(&desc->attr, 0, sizeof(desc->attr));
184 
185 	desc->attr.edge_flags = edge_flags;
186 	desc->attr.line_id = line_id;
187 	desc->attr.line_data = data;
188 	if (name) {
189 		name =  kstrdup_const(name, GFP_KERNEL);
190 		if (!name)
191 			return -ENOMEM;
192 	}
193 
194 	desc->attr.name = name;
195 
196 	return 0;
197 }
198 /* TODO: Implement the functions and remove the ifndef guard */
199 }
200 static int hte_edge_setup(struct line *line, u64 eflags)
201 {
202 	int ret;
203 	unsigned long flags = 0;
204 	struct hte_ts_desc *hdesc = &line->hdesc;
205 
206 	if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING)
207 		flags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
208 				 HTE_FALLING_EDGE_TS :
209 				 HTE_RISING_EDGE_TS;
210 	if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
211 		flags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
212 				 HTE_RISING_EDGE_TS :
213 				 HTE_FALLING_EDGE_TS;
214 
215 	line->total_discard_seq = 0;
216 
217 	hte_init_line_attr(hdesc, desc_to_gpio(line->desc), flags, NULL,
218 			   line->desc);
219 
220 	ret = hte_ts_get(NULL, hdesc, 0);
221 	if (ret)
222 		return ret;
223 
224 	return hte_request_ts_ns(hdesc, process_hw_ts, process_hw_ts_thread,
225 				 line);
226 }
227 static inline bool line_has_supinfo(struct line *line)
228 {
229 	return READ_ONCE(line->debounce_period_us);
230 }
231 int desc_to_gpio(const struct gpio_desc *desc)
232 {
233 	return desc->gdev->base + (desc - &desc->gdev->descs[0]);
234 }
235 void rb_erase(struct rb_node *node, struct rb_root *root)
236 {
237 	struct rb_node *rebalance;
238 	rebalance = __rb_erase_augmented(node, root, &dummy_callbacks);
239 	if (rebalance)
240 		____rb_erase_color(rebalance, root, dummy_rotate);
241 }
242 int hte_ts_get(struct device *dev, struct hte_ts_desc *desc, int index)
243 {
244 	struct hte_device *gdev;
245 	struct hte_ts_info *ei;
246 	const struct fwnode_handle *fwnode;
247 	struct of_phandle_args args;
248 	u32 xlated_id;
249 	int ret;
250 	bool free_name = false;
251 
252 	if (!desc)
253 		return -EINVAL;
254 
255 	fwnode = dev ? dev_fwnode(dev) : NULL;
256 
257 	if (is_of_node(fwnode))
258 		gdev = hte_of_get_dev(dev, desc, index, &args, &free_name);
259 	else
260 		gdev = hte_get_dev(desc);
261 
262 	if (IS_ERR(gdev)) {
263 		pr_err("%s() no hte dev found\n", __func__);
264 		return PTR_ERR(gdev);
265 	}
266 
267 	if (!try_module_get(gdev->owner))
268 		return -ENODEV;
269 
270 	if (!gdev->chip) {
271 		pr_err("%s(): requested id does not have provider\n",
272 		       __func__);
273 		ret = -ENODEV;
274 		goto put;
275 	}
276 
277 	if (is_of_node(fwnode)) {
278 		if (!gdev->chip->xlate_of)
279 			ret = -EINVAL;
280 		else
281 			ret = gdev->chip->xlate_of(gdev->chip, &args,
282 						   desc, &xlated_id);
283 	} else {
284 		if (!gdev->chip->xlate_plat)
285 			ret = -EINVAL;
286 		else
287 			ret = gdev->chip->xlate_plat(gdev->chip, desc,
288 						     &xlated_id);
289 	}
290 
291 	if (ret < 0)
292 		goto put;
293 
294 	ei = &gdev->ei[xlated_id];
295 
296 	ret = hte_bind_ts_info_locked(ei, desc, xlated_id);
297 	if (ret)
298 		goto put;
299 
300 	ei->free_attr_name = free_name;
301 
302 	return 0;
303 
304 put:
305 	module_put(gdev->owner);
306 	return ret;
307 }
308 static int edge_detector_setup(struct line *line,
309 			       struct gpio_v2_line_config *lc,
310 			       unsigned int line_idx, u64 edflags)
311 {
312 	u32 debounce_period_us;
313 	unsigned long irqflags = 0;
314 	u64 eflags;
315 	int irq, ret;
316 
317 	eflags = edflags & GPIO_V2_LINE_EDGE_FLAGS;
318 	if (eflags && !kfifo_initialized(&line->req->events)) {
319 		ret = kfifo_alloc(&line->req->events,
320 				  line->req->event_buffer_size, GFP_KERNEL);
321 		if (ret)
322 			return ret;
323 	}
324 	if (gpio_v2_line_config_debounced(lc, line_idx)) {
325 		debounce_period_us = gpio_v2_line_config_debounce_period(lc, line_idx);
326 		ret = debounce_setup(line, debounce_period_us);
327 		if (ret)
328 			return ret;
329 		line_set_debounce_period(line, debounce_period_us);
330 	}
331 
332 	/* detection disabled or sw debouncer will provide edge detection */
333 	if (!eflags || READ_ONCE(line->sw_debounced))
334 		return 0;
335 
336 	if (IS_ENABLED(CONFIG_HTE) &&
337 	    (edflags & GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE))
338 		return hte_edge_setup(line, edflags);
339 
340 	irq = gpiod_to_irq(line->desc);
341 	if (irq < 0)
342 		return -ENXIO;
343 
344 	if (eflags & GPIO_V2_LINE_FLAG_EDGE_RISING)
345 		irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
346 			IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
347 	if (eflags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
348 		irqflags |= test_bit(FLAG_ACTIVE_LOW, &line->desc->flags) ?
349 			IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
350 	irqflags |= IRQF_ONESHOT;
351 
352 	/* Request a thread to read the events */
353 	ret = request_threaded_irq(irq, edge_irq_handler, edge_irq_thread,
354 				   irqflags, line->req->label, line);
355 	if (ret)
356 		return ret;
357 
358 	line->irq = irq;
359 	return 0;
360 }
361 static inline void rb_link_node(struct rb_node *node, struct rb_node *parent,
362 				struct rb_node **rb_link)
363 {
364 	node->__rb_parent_color = (unsigned long)parent;
365 	node->rb_left = node->rb_right = NULL;
366 
367 	*rb_link = node;
368 }
369 int hte_request_ts_ns(struct hte_ts_desc *desc, hte_ts_cb_t cb,
370 		      hte_ts_sec_cb_t tcb, void *data)
371 {
372 	int ret;
373 	struct hte_ts_info *ei;
374 
375 	if (!desc || !desc->hte_data || !cb)
376 		return -EINVAL;
377 
378 	ei = desc->hte_data;
379 	if (!ei || !ei->gdev)
380 		return -EINVAL;
381 
382 	ret = __hte_req_ts(desc, cb, tcb, data);
383 	if (ret < 0) {
384 		dev_err(ei->gdev->chip->dev,
385 			"failed to request id: %d\n", desc->attr.line_id);
386 		return ret;
387 	}
388 
389 	return 0;
390 }
391 static inline unsigned long pinconf_to_config_packed(enum pin_config_param param,
392 						     u32 argument)
393 {
394 	return PIN_CONF_PACKED(param, argument);
395 }
396 static int gpiod_get_raw_value_commit(const struct gpio_desc *desc)
397 {
398 	struct gpio_chip	*gc;
399 	int value;
400 
401 	gc = desc->gdev->chip;
402 	value = gpio_chip_get_value(gc, desc);
403 	value = value < 0 ? value : !!value;
404 	trace_gpio_value(desc_to_gpio(desc), 1, value);
405 	return value;
406 }
407 static void supinfo_insert(struct line *line)
408 {
409 	struct rb_node **new = &(supinfo_tree.rb_node), *parent = NULL;
410 	struct line *entry;
411 
412 	guard(spinlock)(&supinfo_lock);
413 
414 	while (*new) {
415 		entry = container_of(*new, struct line, node);
416 
417 		parent = *new;
418 		if (line->desc < entry->desc) {
419 			new = &((*new)->rb_left);
420 		} else if (line->desc > entry->desc) {
421 			new = &((*new)->rb_right);
422 		} else {
423 			/* this should never happen */
424 			WARN(1, "duplicate line inserted");
425 			return;
426 		}
427 	}
428 
429 	rb_link_node(&line->node, parent, new);
430 	rb_insert_color(&line->node, &supinfo_tree);
431 }
432 static int debounce_setup(struct line *line, unsigned int debounce_period_us)
433 {
434 	unsigned long irqflags;
435 	int ret, level, irq;
436 
437 	/* try hardware */
438 	ret = gpiod_set_debounce(line->desc, debounce_period_us);
439 	if (!ret) {
440 		line_set_debounce_period(line, debounce_period_us);
441 		return ret;
442 	}
443 	if (ret != -ENOTSUPP)
444 		return ret;
445 
446 	if (debounce_period_us) {
447 		/* setup software debounce */
448 		level = gpiod_get_raw_value_cansleep(line->desc);
449 		if (level < 0)
450 			return level;
451 
452 		if (!(IS_ENABLED(CONFIG_HTE) &&
453 		      test_bit(FLAG_EVENT_CLOCK_HTE, &line->desc->flags))) {
454 			irq = gpiod_to_irq(line->desc);
455 			if (irq < 0)
456 				return -ENXIO;
457 
458 			irqflags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING;
459 			ret = request_irq(irq, debounce_irq_handler, irqflags,
460 					  line->req->label, line);
461 			if (ret)
462 				return ret;
463 			line->irq = irq;
464 		} else {
465 			ret = hte_edge_setup(line, GPIO_V2_LINE_FLAG_EDGE_BOTH);
466 			if (ret)
467 				return ret;
468 		}
469 
470 		WRITE_ONCE(line->level, level);
471 		WRITE_ONCE(line->sw_debounced, 1);
472 	}
473 	return 0;
474 }
```
which has a vulnerability among CWE-476 and among lines:
```
26 	if (!eflags || READ_ONCE(line->sw_debounced))
```
Please generate five possible patches for the vulnerability.