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2f11748432
When `timerqueue_getnext()` is called on an empty timer queue, it will
use `rb_entry()` on a NULL pointer, which is invalid. Fix that by using
`rb_entry_safe()` which handles NULL pointers.
This has not caused any issues so far because the offset of the `rb_node`
member in `timerqueue_node` is 0, so `rb_entry()` is essentially a no-op.
Fixes: 511885d706 ("lib/timerqueue: Rely on rbtree semantics for next timer")
Signed-off-by: Barnabás Pőcze <pobrn@protonmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20221114195421.342929-1-pobrn@protonmail.com
61 lines
1.4 KiB
C
61 lines
1.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_TIMERQUEUE_H
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#define _LINUX_TIMERQUEUE_H
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#include <linux/rbtree.h>
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#include <linux/ktime.h>
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struct timerqueue_node {
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struct rb_node node;
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ktime_t expires;
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};
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struct timerqueue_head {
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struct rb_root_cached rb_root;
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};
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extern bool timerqueue_add(struct timerqueue_head *head,
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struct timerqueue_node *node);
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extern bool timerqueue_del(struct timerqueue_head *head,
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struct timerqueue_node *node);
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extern struct timerqueue_node *timerqueue_iterate_next(
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struct timerqueue_node *node);
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/**
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* timerqueue_getnext - Returns the timer with the earliest expiration time
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*
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* @head: head of timerqueue
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*
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* Returns a pointer to the timer node that has the earliest expiration time.
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*/
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static inline
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struct timerqueue_node *timerqueue_getnext(struct timerqueue_head *head)
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{
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struct rb_node *leftmost = rb_first_cached(&head->rb_root);
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return rb_entry_safe(leftmost, struct timerqueue_node, node);
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}
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static inline void timerqueue_init(struct timerqueue_node *node)
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{
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RB_CLEAR_NODE(&node->node);
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}
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static inline bool timerqueue_node_queued(struct timerqueue_node *node)
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{
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return !RB_EMPTY_NODE(&node->node);
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}
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static inline bool timerqueue_node_expires(struct timerqueue_node *node)
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{
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return node->expires;
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}
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static inline void timerqueue_init_head(struct timerqueue_head *head)
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{
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head->rb_root = RB_ROOT_CACHED;
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}
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#endif /* _LINUX_TIMERQUEUE_H */
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