From 21bec0ebb854e358c6c3be55af553131808323c3 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Barnab=C3=A1s=20P=C5=91cze?= Date: Mon, 14 Nov 2022 19:54:23 +0000 Subject: [PATCH] timerqueue: Use rb_entry_safe() in timerqueue_getnext() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit [ Upstream commit 2f117484329b233455ee278f2d9b0a4356835060 ] 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: 511885d7061e ("lib/timerqueue: Rely on rbtree semantics for next timer") Signed-off-by: Barnabás Pőcze Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20221114195421.342929-1-pobrn@protonmail.com Signed-off-by: Sasha Levin --- include/linux/timerqueue.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/timerqueue.h b/include/linux/timerqueue.h index 9388408..adc80e2 100644 --- a/include/linux/timerqueue.h +++ b/include/linux/timerqueue.h @@ -35,7 +35,7 @@ struct timerqueue_node *timerqueue_getnext(struct timerqueue_head *head) { struct rb_node *leftmost = rb_first_cached(&head->rb_root); - return rb_entry(leftmost, struct timerqueue_node, node); + return rb_entry_safe(leftmost, struct timerqueue_node, node); } static inline void timerqueue_init(struct timerqueue_node *node) -- 2.7.4