2022-11-14 21:08:51

by Barnabás Pőcze

Subject: [PATCH v2] timerqueue: use rb_entry_safe() in timerqueue_getnext()

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 <[email protected]>
---
changes in v2:
- reword commit message

---
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 93884086f392..adc80e29168e 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)
--
2.38.1

2022-11-17 10:54:45

by tip-bot2 for Borislav Petkov (AMD)

Subject: [tip: timers/core] timerqueue: Use rb_entry_safe() in timerqueue_getnext()

The following commit has been merged into the timers/core branch of tip:

Commit-ID: 2f117484329b233455ee278f2d9b0a4356835060
Gitweb: https://git.kernel.org/tip/2f117484329b233455ee278f2d9b0a4356835060
Author: Barnabás Pőcze <[email protected]>
AuthorDate: Mon, 14 Nov 2022 19:54:23
Committer: Thomas Gleixner <[email protected]>
CommitterDate: Thu, 17 Nov 2022 11:26:20 +01:00

timerqueue: Use rb_entry_safe() in timerqueue_getnext()

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 <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

---
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)