From: Barnabás Pőcze pobrn@protonmail.com
[ 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 pobrn@protonmail.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Link: https://lore.kernel.org/r/20221114195421.342929-1-pobrn@protonmail.com Signed-off-by: Sasha Levin sashal@kernel.org --- 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 42868a9b4365..df7841c6fdf4 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)