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| author | Uladzislau Rezki (Sony) <urezki@gmail.com> | 2025-06-10 19:34:48 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-07-10 16:05:08 +0200 |
| commit | 42c5a4b47d4a1959d564f4ad1fea59bbb28eae1d (patch) | |
| tree | 253653bdb166366356cee2d8e1df456b4d6c5aeb | |
| parent | c40b207cafd006c610832ba52a81cedee77adcb9 (diff) | |
rcu: Return early if callback is not specified
[ Upstream commit 33b6a1f155d627f5bd80c7485c598ce45428f74f ]
Currently the call_rcu() API does not check whether a callback
pointer is NULL. If NULL is passed, rcu_core() will try to invoke
it, resulting in NULL pointer dereference and a kernel crash.
To prevent this and improve debuggability, this patch adds a check
for NULL and emits a kernel stack trace to help identify a faulty
caller.
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | kernel/rcu/tree.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index cefa831c8cb3..552464dcffe2 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -3076,6 +3076,10 @@ __call_rcu_common(struct rcu_head *head, rcu_callback_t func, bool lazy_in) /* Misaligned rcu_head! */ WARN_ON_ONCE((unsigned long)head & (sizeof(void *) - 1)); + /* Avoid NULL dereference if callback is NULL. */ + if (WARN_ON_ONCE(!func)) + return; + if (debug_rcu_head_queue(head)) { /* * Probable double call_rcu(), so leak the callback. |