[PATCH 4/4] kcsan, debugfs: avoid updating white/blacklist with the same value

From: ran xiaokai
Date: Wed Sep 25 2024 - 10:59:57 EST


From: Ran Xiaokai <ran.xiaokai@xxxxxxxxxx>

When userspace passes a same white/blacklist value as it for now,
the update is actually not necessary.

Signed-off-by: Ran Xiaokai <ran.xiaokai@xxxxxxxxxx>
---
kernel/kcsan/debugfs.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/kernel/kcsan/debugfs.c b/kernel/kcsan/debugfs.c
index d5e624c37125..6b05115d5b73 100644
--- a/kernel/kcsan/debugfs.c
+++ b/kernel/kcsan/debugfs.c
@@ -142,6 +142,9 @@ static ssize_t set_report_filterlist_whitelist(bool whitelist)
old_list = rcu_dereference_protected(rp_flist,
lockdep_is_held(&rp_flist_mutex));

+ if (old_list->whitelist == whitelist)
+ goto out;
+
new_list = kzalloc(sizeof(*new_list), GFP_KERNEL);
if (!new_list) {
ret = -ENOMEM;
--
2.15.2