From: Barnabás Pőcze Date: Mon, 14 Nov 2022 19:54:23 +0000 (+0000) Subject: timerqueue: Use rb_entry_safe() in timerqueue_getnext() X-Git-Tag: v4.9.337~220 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b1c63d8af4eb062c2e18110d869e7a2e14be61d1;p=thirdparty%2Fkernel%2Fstable.git timerqueue: Use rb_entry_safe() in timerqueue_getnext() [ 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 --- diff --git a/include/linux/timerqueue.h b/include/linux/timerqueue.h index 42868a9b43657..df7841c6fdf41 100644 --- a/include/linux/timerqueue.h +++ b/include/linux/timerqueue.h @@ -34,7 +34,7 @@ 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)