From: Paul E. McKenney <paulmck@kernel.org>
Date: Wed, 12 Feb 2020 21:29:15 +0000 (-0800)
Subject: rculist: Add ASSERT_EXCLUSIVE_ACCESS() to __list_splice_init_rcu()
X-Git-Tag: v5.9-rc1~203^2~2^2~10
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c93773c1a3fedf6c3f6fa12833e2b74a9897c3e3;p=thirdparty%2Fkernel%2Flinux.git

rculist: Add ASSERT_EXCLUSIVE_ACCESS() to __list_splice_init_rcu()

After the sync() in __list_splice_init_rcu(), there should be no
readers traversing the old list.  This commit therefore enlists the
help of KCSAN to verify this condition via a pair of calls to
ASSERT_EXCLUSIVE_ACCESS().

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Marco Elver <elver@google.com>
---

diff --git a/include/linux/rculist.h b/include/linux/rculist.h
index df587d181844b..2ebd112f86f72 100644
--- a/include/linux/rculist.h
+++ b/include/linux/rculist.h
@@ -248,6 +248,8 @@ static inline void __list_splice_init_rcu(struct list_head *list,
 	 */
 
 	sync();
+	ASSERT_EXCLUSIVE_ACCESS(*first);
+	ASSERT_EXCLUSIVE_ACCESS(*last);
 
 	/*
 	 * Readers are finished with the source list, so perform splice.